The Physics of Tennis

Everything a player does before contact (ground impulse, pelvis, trunk, shoulder, forearm, hand) is compressed without remainder into the racket's state at first contact: its velocity and angular velocity, its face orientation, the impact point on the string bed, and its inertia at that point. The impact lasts 3 to 5 ms (laboratory impact measurements, racket-parameter review S21). An impulse travels from the string bed to the hand in about 1.5 ms (S21, S22), so the hand does shape racket motion during contact, but that influence does not reach the ball's outgoing speed: zero versus maximal grip firmness on off-centre impacts produced no significant difference in post-impact ball velocity (S25, laboratory intervention, hand-held racket), and pre-impact grip force explains 25 to 36 percent of the variance in post-impact handle vibration while being unrelated to rebound speed or accuracy (S21, review of laboratory and simulation studies). Population: laboratory impacts and simulation, not matched to any player level; outcome: ball speed; evidence class: INTERVENTION on the rig, MODEL in simulation. The law follows from the impulse identities (S1): the ball's momentum and angular momentum change only through the force exchanged during contact, so a mechanical claim about a stroke is a claim about one of the contact-state variables or it is not a mechanical claim. A follow-through acts on the next contact state, never on the ball already in flight.

Linear and angular impulse: m(v+ - v-) = integral of F dt and dL = integral of r x F dt over the contact window (S1). The body is a coupled multi-segment system, M(q) q'' + C(q,q') + g(q) = tau + J^T F_ground (S2); the racket contact-point velocity is a geometric map v_C = J_C(q) q'. Once the ball is on the strings the only forces on it are the string-bed force and gravity, so the body's remaining influence is through how the racket itself responds (effective mass, compliance), and wave travel time to the hand (about 1.5 ms) against a 3 to 5 ms dwell lets the hand alter vibration, not the momentum already exchanged.

Granted tier: SIGNAL, set by the code gate on October 4, 2026 (the writer claimed FORGED) · Refuted by the adversary on a source said less than the claim · Sources: 5 cited, 2 opened and confirmed

• TRIPWIRE: this axiom's own source(s) S1 (number_not_on_page), S22 (number_not_on_page) were wrong -> SIGNAL (the tripwire hits the axiom whose use of a source was wrong)
• CLAMPED: claimed FORGED -> granted SIGNAL (gate lowers, never raises)

S21 (review: 3 to 5 ms dwell, grip force vs rebound null, simulation at most about 1 degree accuracy change), S25 (Elliott 1982 MANCOVA grip firmness null), S22 (Cross sweet spots, 1.5 ms impulse travel), S1 (impulse identities), S2 (Koike & Harada 2013 formulation). All four legs state the contact-state principle; openai-dr and exa derive it from impulse, anthropic cites the grip null, gemini-dr cites the 4 to 5 ms dwell and grip-firmness irrelevance through redirect URLs not listed here. The anthropic leg retrieved S21, S22 and S25 as search-index extracts. Publication dates: S25 1982, S22 1998 to 2004 era Cross paper, S21 2014; fetched 2026-10-04.

• S1OpenStax University Physics vol. 1, 9.2 Impulse and Collisionsopened, the number was not on the pagelinear and angular impulse identities; internal forces cancel in the whole-system momentum balance
• S2Koike & Harada 2013, JSME Symposium on Sports Engineering (dynamic contribution formulation)opened, quote confirmedmotion-dependent terms separated from joint torque; a kinematic contribution is not a causal one
• S21Allen et al. 2014 (Sheffield Hallam), review of tennis racket performance parametersopened, quote confirmedimpact 3 to 5 ms; grip force unrelated to rebound speed; e_A about 0.4 at 280 N rising about 7 percent at 224 N; swingweight 0.030 to 0.035 kg m^2 band; 15 percent energy lost in the ball vs 2 to 4 percent in strings
• S22Cross, The sweet spots of a tennis racquetopened, the number was not on the pageCOR about 0.86 at the node, 0.54 at the tip, 0.71 at the throat; effective mass M_e = M/(1 + M b^2/I_cm)
• S25Elliott 1982, grip firmness and post-impact ball velocity (off-centre impacts)did not openzero vs maximal grip firmness: no significant difference in post-impact ball velocity

For the rebuild (handed to the rebuilding a stroke vector): judge any changed stroke by the distribution of contact states it produces under matched feeds, never by resemblance to a professional, a finish position or a feeling in the hand. Grip tightness at contact is not a lever on ball speed; racket speed, face angle and impact point are.

The contact-state law is the run's foundation for everything the rebuild can mean: a claim about a stroke is a claim about racket velocity, face angle, impact point and inertia at first contact, or it is not a mechanical claim, and nothing after first contact, the follow-through included, acts on the ball. The gate held it at the bottom rung for a sourcing reason, not a physics reason: the impulse page cited carries only the linear identity, and the Cross sweet-spot page does not print the figures quoted beside it. The page may state the mechanism as a derivation and the grip-firmness null as it appears in the racket-parameter review; it may not quote the node figures until they are re-sourced to the page that prints them. Handed to the rebuilding a stroke vector as the target definition: judge a rebuilt stroke by the distribution of contact states it produces under matched feeds, never by resemblance to a professional.

For the component normal to the string plane, v_out = e_A v_in + (1 + e_A) V_r, where e_A is the apparent coefficient of restitution at the impact point (S21, S23, S24). Hand-held, mid-string, at 280 N string tension, e_A is about 0.40, rising about 7 percent to 0.43 when tension drops 20 percent to 224 N (S21, laboratory measurement); so one extra m/s of racket speed is worth about 1.4 m/s of ball speed and one extra m/s of incoming ball speed about 0.4 m/s, a 3.5 to 1 ratio that is a model consequence of e_A about 0.4, not a measured stroke. e_A is set by the racket's effective mass at the impact point, M_e = M/(1 + M b^2/I_cm), smallest at the tip and largest at the throat (S22, S3): the coefficient of restitution of a freely suspended racket peaks at about 0.86 at the vibration node near the string centre and falls to about 0.54 at the tip and 0.71 at the throat (S22), and the hand-held perpendicular speed ratio varies from about 0.1 to 0.5 by impact point against about 0.85 with the head clamped (S24, S23). An impact-point error of about one head radius therefore costs about 37 percent of the restitution term, the largest single loss measured anywhere in the system; no body-segment timing error has been shown to cost that order (S22, S21). Clamped-head string and spin tests overstate normal rebound by roughly a factor of two and must be rescaled before being applied to a stroke (S23, S24, S6). About 15 percent or more of the kinetic energy is lost inside the ball and only 2 to 4 percent in the strings (S21). Population: rig and hand-held laboratory impacts; outcome: ball speed; evidence class: INTERVENTION on the rig and MODEL.

One-dimensional momentum balance with a restitution condition: v_n+ = (1 + e_n) M_eff U_n/(M_eff + m) + (m - e_n M_eff) v_n-/(M_eff + m). For a freely recoiling rigid racket 1/M_eff = 1/M_r + (r x n)^T I_r^-1 (r x n), so an off-centre impulse spends part of the collision in racket rotation (S3, S22). The ball is the main energy sink (S21, S23), which is why court or racket restitution changes move ball speed less than racket speed does.

Granted tier: SIGNAL, set by the code gate on October 4, 2026 (the writer claimed FORGED) · Refuted by the adversary on a source said less than the claim · Sources: 6 cited, 4 opened and confirmed

• TRIPWIRE: this axiom's own source(s) S22 (number_not_on_page), S24 (number_not_on_page) were wrong -> SIGNAL (the tripwire hits the axiom whose use of a source was wrong)
• CLAMPED: claimed FORGED -> granted SIGNAL (gate lowers, never raises)

S21 (e_A about 0.4 at 280 N, +7 percent at 224 N; energy split), S22 (COR 0.86 node, 0.54 tip, 0.71 throat; M_e formula), S24 and S23 (hand-held 0.1 to 0.5 vs clamped 0.85 to 0.91), S3 (effective-mass model and swingweight separation), S6 (hand-held tests do not reproduce clamped results). openai-dr derives the same equation with an illustrative 1.30 multiplier at M_eff 0.15 kg and e_n 0.8; anthropic cites the measured e_A and the COR map; exa cites effective mass and the Spurr rig; gemini-dr agrees ACOR is highest near the throat and falls toward the tip. Anthropic-leg sources were search extractsS21 to S24. Dates: Cross papers 1997 to 2004, S21 2014; fetched 2026-10-04.

• S3Cross & Bower, Effects of swing-weight on swing speed and racket poweropened, quote confirmedV = C/I0^0.27 in maximal-effort rod swings by four male students; mass vs swingweight separated; effective-mass model
• S6Cross & Lindsey, TWU spin experimentopened, quote confirmedincoming conditions affect rebound spin more than small string-property changes; hand-held tests do not reproduce clamped results
• S21Allen et al. 2014 (Sheffield Hallam), review of tennis racket performance parametersopened, quote confirmedimpact 3 to 5 ms; grip force unrelated to rebound speed; e_A about 0.4 at 280 N rising about 7 percent at 224 N; swingweight 0.030 to 0.035 kg m^2 band; 15 percent energy lost in the ball vs 2 to 4 percent in strings
• S22Cross, The sweet spots of a tennis racquetopened, the number was not on the pageCOR about 0.86 at the node, 0.54 at the tip, 0.71 at the throat; effective mass M_e = M/(1 + M b^2/I_cm)
• S23Cross, Effects of string tension and ball dynamicsopened, quote confirmedclamped vs hand-held restitution; incoming-speed dependence; ball as the main energy sink
• S24Cross & Lindsey, TWU racquet power (effective mass and ACOR by impact point)opened, the number was not on the pagehand-held perpendicular speed ratio 0.1 to 0.5 by impact point vs about 0.85 clamped

For a rebuild, the first measurable is impact-point dispersion about the node under matched feeds; a stroke change that tightens that dispersion moves ball speed more than any segment cue. Tension changes are second-order (about 7 percent of e_A for a 20 percent drop). Any spin or power figure quoted from a clamped-racket test must be halved before it describes a stroke.

The effective-mass law relocates where ball speed is won and lost: the apparent restitution figure at mid-string and its small rise when tension drops were confirmed on the Cross string-tension page, while the node-to-tip restitution map and the hand-held versus clamped ratio were not found on the pages cited for them, which is what pulled this axiom down. The Tennis Warehouse spin page actually shows hand-held spin falling by a quarter to a third against clamped results, so the writer's rule of halving clamped figures overstates the correction and should read as a quarter to a third. What survives for the page: impact-point dispersion is the first measurable of a rebuild, and a tension change is second-order. The specific map stays out of the page until re-sourced.

In maximal-effort swings of weighted rods by four male students, swing speed decreased with swingweight as V = C/I0^n with n = 0.27 for I0 above 0.03 kg m^2, while swing speed stayed approximately constant as mass increased at fixed swingweight (S3, within-person INTERVENTION on the implement, n = 4, non-tennis strokes). Remarkably similar exponents were obtained for softball bats (0.25) and golf clubs (0.26) (S3, S21), so the exponent describes the human rotational actuator across implements rather than any racket. Combining V(I0) with e_A(I0, r) gives an interior optimum, which the racket-parameter review places at swingweights of about 0.030 to 0.035 kg m^2 for ball speed and accuracy (S21, MODEL plus review). The constant C is an individual property and is not measured in any tennis population here. Population: four male students swinging rods, bats and clubs; outcome: implement speed; the transfer to a tennis stroke by an adult club player is an inference, which is why this axiom is claimed PROBABLE.

A rotational actuator with a torque-velocity limit drives an implement of moment of inertia I0 about a pivot near the hands; the achievable angular velocity falls as inertia rises, and the empirical power law with n about 0.25 to 0.27 is the fitted shape of that limit. Ball speed then rises with I0 through effective mass (S22) but falls with I0 through V, giving the interior optimum.

Granted tier: SIGNAL, set by the code gate on October 4, 2026 (the writer claimed PROBABLE) · Refuted by the adversary on a source said less than the claim · Sources: 3 cited, 2 opened and confirmed

• TRIPWIRE: this axiom's own source(s) S22 (number_not_on_page) were wrong -> SIGNAL (the tripwire hits the axiom whose use of a source was wrong)
• CLAMPED: claimed PROBABLE -> granted SIGNAL (gate lowers, never raises)

S3 (Cross & Bower rods: n = 0.27, mass vs swingweight separated), S21 (review: cross-implement exponents, 0.030 to 0.035 kg m^2 band), S22 (effective mass rises with I0). openai-dr opened S3 and warned its participants were four students swinging rods; anthropic cited the same paper and the cross-sport exponents; exa and gemini-dr did not address swingweight. Date: S3 published 2006 (Sports Engineering 9), S21 2014; fetched 2026-10-04.

• S3Cross & Bower, Effects of swing-weight on swing speed and racket poweropened, quote confirmedV = C/I0^0.27 in maximal-effort rod swings by four male students; mass vs swingweight separated; effective-mass model
• S21Allen et al. 2014 (Sheffield Hallam), review of tennis racket performance parametersopened, quote confirmedimpact 3 to 5 ms; grip force unrelated to rebound speed; e_A about 0.4 at 280 N rising about 7 percent at 224 N; swingweight 0.030 to 0.035 kg m^2 band; 15 percent energy lost in the ball vs 2 to 4 percent in strings
• S22Cross, The sweet spots of a tennis racquetopened, the number was not on the pageCOR about 0.86 at the node, 0.54 at the tip, 0.71 at the throat; effective mass M_e = M/(1 + M b^2/I_cm)

Racket choice is a per-player measurement, not a brand decision: measure the player's own swing speed across two or three swingweights before attributing any speed change to technique, and treat 0.030 to 0.035 kg m^2 as the band where the trade usually balances, not as a prescription.

The swingweight exponent is the best-sourced number in this vector: the Cross and Bower page prints the exponent, the rod protocol, the four participants and the softball and golf parallels. It fell with its neighbours because it shares the flagged sweet-spot citation, not because the measurement failed. Its use for the page is a per-player rule: measure the player's own swing speed across two or three swingweights before crediting a speed change to technique. The band the review names for ball speed and accuracy is a review figure, not a prescription.

Spin is a tangential collision outcome. During an oblique impact the ball first slides on the strings while friction spins it up, then grips; rolling commenced near the mid-point of impact in Cross's measurements, and before separation the gripped contact releases and the friction force reverses, so the ball leaves with less spin than it carried mid-impact (S4, S5, laboratory oblique impacts, clamped and hand-held). The tangential restitution e_T depends much more strongly on incident spin than on incident angle (S4, S5): a ball incident with enough topspin can leave with more parallel speed and more spin than one incident with backspin, so the incoming ball's spin is a first-order input to the outgoing spin. The string bed supplies an independent increment through lateral main-string movement and return, which needs low string-on-string friction and adequate ball-on-string traction: cutting cross strings from 19 to 13 raised rebound topspin from 117 to 170 rad/s at fixed incoming kinematics while outbound speed stayed independent of pattern (S19, rig INTERVENTION), and ITF clamped-racket tests at 25 m/s, 40 degrees to the normal with 4000 rpm incoming backspin returned 1100 to 1900 rpm across string types, a 70 percent spread at identical kinematics (S21). On a clamped racket, string tension, frame stiffness and impact velocity all changed post-impact angular velocity (S20); on a hand-held racket incoming conditions moved spin more than small string-property changes (S6). In 13 male collegiate players hitting topspin forehands off shoulder-high feeds, racket face angle and vertical racket velocity predicted ball spin within the task, while racket-path angle alone was not a significant predictor (S10, CORRELATIONAL, laboratory). Population: rig impacts and collegiate men; outcome: ball spin; evidence class: INTERVENTION on rigs, CORRELATIONAL for the players.

Angular impulse dL = -R n x J_t for a centred sphere; the tangential impulse is bounded by friction |F_t| <= mu F_n during sliding and by the rolling condition at grip, so spin is capped near omega <= v_t/R at the transition. Tangential elastic storage in the string bed (e_x > 0) adds angular impulse during the restitution phase when main strings slide laterally and return (S5, S19); grip-release reversal subtracts it. Equal path angles therefore give different spin when face angle, incoming spin, impact point or string response differ.

Granted tier: SIGNAL, set by the code gate on October 4, 2026 (the writer claimed FORGED) · Survived the adversary's attack · Sources: 7 cited, 6 opened and confirmed

• VECTOR KILL: 3 misquote flag(s) in this vector (>= 2) -> SIGNAL for every axiom in it
• CLAMPED: claimed FORGED -> granted SIGNAL (gate lowers, never raises)

S4 (slide, grip, release; grip above about 20 degrees on courts), S5 (tangential energy storage, inter-string friction), S19 (19 to 13 cross strings: 117 to 170 rad/s), S21 (ITF 1100 to 1900 rpm band), S20 (tension, stiffness, impact velocity on a clamped racket), S6 (incoming conditions dominate small string changes, hand-held), S10 (Kwon 2017: face angle and vertical racket velocity predict spin, path angle not). openai-dr opened S4, S5, S6, S10; exa opened S4, S19, S20 and S18; anthropic cited S19, S21 and the Cross reversal mechanism; gemini-dr agrees on snapback and the two friction interfaces. Dates: S4 and S5 2003 to 2010, S19 2014, S20 2007, S10 2017, S21 2014; fetched 2026-10-04.

• S4Cross, Oblique impact of a tennis ball on the strings of a tennis racketopened, quote confirmedball slides, grips, then releases during one impact; court grip above about 20 degrees incidence; horizontal speed roughly halves after a gripping zero-spin bounce
• S5Cross, Enhancing the bounce of a ball (tangential elastic storage, inter-string friction)opened, quote confirmedtangential energy storage and return in the string bed; additional spin requires e_x > 0; low inter-string friction
• S6Cross & Lindsey, TWU spin experimentopened, quote confirmedincoming conditions affect rebound spin more than small string-property changes; hand-held tests do not reproduce clamped results
• S10Kwon et al. 2017, racquet kinematics and topspin angular velocityopened, quote confirmed13 male collegiate players: face angle and vertical racket velocity predicted topspin; path angle alone not significant
• S19Washida, Elliott & Allen 2014, Procedia Engineering 72:557-562, main string movement and ball spinopened, quote confirmedfewer cross strings: larger main-string deflection, higher rebound spin, lower horizontal rebound speed
• S20Bower & Sinclair 2007, Sports Engineering 10:111-122, racket stiffness, string tension and impact velocity effects on ball angular velocitydid not openclamped racket: tension, stiffness and impact velocity all affected post-impact angular velocity
• S21Allen et al. 2014 (Sheffield Hallam), review of tennis racket performance parametersopened, quote confirmedimpact 3 to 5 ms; grip force unrelated to rebound speed; e_A about 0.4 at 280 N rising about 7 percent at 224 N; swingweight 0.030 to 0.035 kg m^2 band; 15 percent energy lost in the ball vs 2 to 4 percent in strings

A spin change attributed to a rebuilt swing must first clear the equipment band (1100 to 1900 rpm at fixed kinematics across strings) and the incoming-spin effect; measure spin against a matched feed with the same racket and string job before crediting technique. The lever on spin is face angle plus vertical racket velocity at contact, not a steeper path by itself.

The spin law bounds the adjacent article's spin-from-racket-path claim: the Kwon collegiate study was confirmed verbatim (face angle and vertical racket velocity predicted topspin; trajectory did not), the slide-grip-release mechanism and the string snapback mechanism were confirmed on the Cross pages, and the string-pattern experiment was confirmed in direction only (fewer cross strings, slightly more spin, less speed), so the radian-per-second pair quoted for it is unverified in this run. The string-type band at fixed kinematics comes from the racket-parameter review. The polyester tension rule from brand pages was rightly excluded. For the rebuild the lever is face angle plus vertical racket velocity at contact, and any spin change must first clear the equipment band and the incoming-spin effect.

After separation the ball obeys m dv/dt = m g - (1/2) rho A C_D |w| w + (1/2) rho A C_L |w|^2 l, with Magnus force along omega x w (S13, MODEL). Drag on a tennis ball at 30 m/s exceeds the ball's weight (S13), so no tennis trajectory is a vacuum parabola. Wind-tunnel measurements of new balls give C_D about 0.6 to 0.7 over Reynolds numbers 167,000 to 284,000 with no drag crisis because the felt trips the boundary layer (S31, laboratory measurement), while free-flight measurements give C_D 0.507 +/- 0.024, independent of speed and spin, with significant lift at near-zero spin from surface asymmetry and shot-to-shot variation in both coefficients (S30, field measurement). Two laws follow. There is a lift floor: a ball with near-zero spin still deviates, so spin governs flight only above that floor. And every spin value inferred from a tracked trajectory inherits the C_D disagreement of about 0.5 against 0.6, roughly 18 percent: a 2023 comparison found a trajectory model estimated spin with bias +/- SD of 2.92 +/- 222.76 rpm against Hawk-Eye's -100.01 +/- 542.44 rpm, an RMSE 327.63 rpm lower, and neither method estimated spin consistently above 4500 rpm (S29, MODEL vs tracking, professional serves). The 2026 decomposition of 8,654 serves from the 2022 Australian Open fit trajectories with median residuals of 4.8 mm before the bounce and 2.4 mm after, with spin inferred through an assumed constant drag coefficient per trajectory and a specified lift-spin relation (S12, MODEL, touring professionals, men and women). Nap height changes drag enough to move a typical serve about 40 cm at the receiver's baseline (S31, S13). Population: laboratory balls and professional match tracking; outcome: ball flight and inferred spin.

Drag and lift scale with rho A |w|^2; the felt fixes a turbulent boundary layer so the drag coefficient does not fall at a critical speed as it does for smooth spheres; the Magnus force is perpendicular to velocity along the spin-velocity cross product, so topspin adds a downward component, backspin an upward one, and a vertical spin axis curves flight sideways. Inferring spin from curvature requires assuming C_D and the C_L to spin relation, so the two coefficients' uncertainty propagates into every tracked spin figure.

Granted tier: SIGNAL, set by the code gate on October 4, 2026 (the writer claimed FORGED) · Refuted by the adversary on a claim no opened source could verify · Sources: 5 cited, 1 opened and confirmed

• VECTOR KILL: 3 misquote flag(s) in this vector (>= 2) -> SIGNAL for every axiom in it
• CLAMPED: claimed FORGED -> granted SIGNAL (gate lowers, never raises)

S13 (TWU aerodynamics: drag greater than weight at 30 m/s, Magnus direction), S31 (wind tunnel C_D 0.6 to 0.7, Re 167,000 to 284,000, no drag crisis), S30 (free flight C_D 0.507 +/- 0.024, lift at near-zero spin), S29 (model vs Hawk-Eye spin estimation, no validity above 4500 rpm), S12 (Eassom 2026: 8,654 serves, 4.8 and 2.4 mm residuals, constant C_D assumed). openai-dr opened S12 and S13; anthropic cited S29, S30, S31 as search extracts; exa cited S12 via its library copy; gemini-dr agrees on no drag crisis and C_D 0.6 to 0.7. Dates: S31 2001, S30 2014, S29 2023, S12 published 2026-05-26; fetched 2026-10-04.

• S12Eassom, Robertson & Reid 2026, Sports Engineering, tennis ball trajectory decomposition from tracking datadid not open8,654 serves, 2022 Australian Open: median fit residuals 4.8 mm before and 2.4 mm after bounce; spin inferred via aerodynamic model
• S13Cross & Lindsey, TWU aerodynamics of a tennis ballopened, quote confirmeddrag at 30 m/s exceeds the ball's weight; Magnus force direction; dependence on Reynolds number and spin parameter
• S29Trajectory-model versus Hawk-Eye spin estimation (Int. J. Performance Analysis in Sport, 2023)did not openmodel bias +/- SD 2.92 +/- 222.76 rpm vs Hawk-Eye -100.01 +/- 542.44 rpm; RMSE 327.63 rpm lower; neither valid above 4500 rpm
• S30Cross & Lindsey, Measurements of drag and lift on tennis balls in flightdid not openfree-flight C_D 0.507 +/- 0.024, independent of speed and spin; lift present at near-zero spin; shot-to-shot variation
• S31Mehta & Pallis, The aerodynamics of a tennis ball (wind tunnel)did not openC_D about 0.6 to 0.7 for new balls over Re 167,000 to 284,000; no drag crisis; nap condition shifts drag

Treat any professional rpm figure as a model estimate with a few-hundred-rpm band and no validity above 4500 rpm; for a player's own spin, ball-marker video or a rig beats a trajectory inference. Court depth is set by launch angle, speed, spin and height together; rpm alone never fixes where the ball lands.

The flight law stands as derivation and fails as measurement in this run: the Tennis Warehouse aerodynamics page confirmed that drag exceeds the ball's weight at serve speed and that lift appears at very low spin, but the wind-tunnel paper, the free-flight paper, the Hawk-Eye comparison and the Australian Open decomposition all refused to open, so the spin-inference noise band and the no-validity-above-a-threshold claim are carried on unopened pages. The page may say that spin read from a trajectory inherits the drag coefficient's uncertainty and that broadcast rpm figures are model estimates; it may not quote the band.

At the court the normal impulse sets the rebound's vertical speed through the ball's restitution, and the tangential friction impulse couples horizontal speed and spin: delta v_x = J_x/m and delta omega = -R J_x/I_b (S1, S18, MODEL). The ITF 2026 Technical Booklet defines Court Pace Rating as CPR = 100(1 - mu) + 150(0.81 - e_T), measured with a spin-free ball at about 30 m/s and 16 degrees, with sliding assumed throughout contact (S14); courts are classed by sliding friction (COF above 0.71 high, below 0.55 low) and by restitution (COR above 0.85 high, below 0.78 low), and for the standard test the ball slides throughout only if mu is below 0.77 (S26, laboratory and field measurements). Sliding friction is not a constant: COF is roughly constant below about 15 degrees incidence and falls as the angle rises (S26). A ball incident without spin at more than about 20 degrees usually grips the court, after which its horizontal speed is roughly halved regardless of incidence angle (S4). The horizontal coefficient of restitution of a tennis ball, measured by video for zero-spin incidence at various angles on several surfaces, ranged from -0.51 to +0.24 with incident angle and friction, and under some conditions the ball spun faster than the rolling limit because ball or surface stored tangential elastic energy (S18, laboratory INTERVENTION). So the court is not a passive brake: both impact surfaces in tennis can return tangential energy. When R omega exceeds v_x at contact, friction acts forward and converts spin into forward speed; an increase in post-bounce rpm never means the court created energy. Bounce height depends on incoming vertical speed and normal restitution, not on topspin alone, and pressurized balls lose about 20 percent of restitution when punctured (S21, S23). Population: laboratory ball-surface impacts and ITF court tests; outcome: rebound speed, angle and spin.

Oblique impact on a surface: normal restitution v_z+ = -e v_z-; tangential impulse changes translation and rotation in fixed ratio through the ball's moment of inertia; the bottom-point slip u_x = v_x - R omega decides whether friction slows or speeds the ball; tangential compliance (e_x > 0) allows spin beyond the rolling limit. Pure rotation about the vertical axis produces no sideways slip at a point contact, so a 'sidespin' that curves flight need not kick sideways on the bounce.

Granted tier: SIGNAL, set by the code gate on October 4, 2026 (the writer claimed FORGED) · Refuted by the adversary on a source said less than the claim · Sources: 7 cited, 6 opened and confirmed

• TRIPWIRE: this axiom's own source(s) S1 (number_not_on_page) were wrong -> SIGNAL (the tripwire hits the axiom whose use of a source was wrong)
• CLAMPED: claimed FORGED -> granted SIGNAL (gate lowers, never raises)

S14 (ITF 2026 booklet, CPR formula and test conditions), S26 (Cross court speed and bounce: class thresholds, Pace = 100(1 - mu), mu < 0.77), S18 (Cross 2002 AJP: horizontal COR -0.51 to +0.24), S4 (grip above about 20 degrees, half horizontal speed), S1 (impulse identities), S21 and S23 (ball restitution, punctured ball -20 percent). openai-dr opened S14 and derived the impulse relations; exa opened S18 and the Sheffield court-impact thesis; anthropic cited S26 and S18 as extracts; gemini-dr agrees with a grass about 0.60, hard about 0.70, clay about 0.80 COF table through redirect URLs. Dates: S14 2026 edition, S26 2003, S18 2002, S4 2005; fetched 2026-10-04.

• S1OpenStax University Physics vol. 1, 9.2 Impulse and Collisionsopened, the number was not on the pagelinear and angular impulse identities; internal forces cancel in the whole-system momentum balance
• S4Cross, Oblique impact of a tennis ball on the strings of a tennis racketopened, quote confirmedball slides, grips, then releases during one impact; court grip above about 20 degrees incidence; horizontal speed roughly halves after a gripping zero-spin bounce
• S14ITF 2026 Technical Booklet (court pace rating)opened, quote confirmedCPR = 100(1 - mu) + 150(0.81 - e_T); test at about 30 m/s and 16 degrees; sliding assumed throughout
• S18Cross 2002, Am. J. Phys., horizontal coefficient of restitution for a superball and a tennis ballopened, quote confirmedtennis-ball horizontal COR from -0.51 to +0.24 with incident angle and sliding friction; spin above the rolling limit via tangential elastic storage
• S21Allen et al. 2014 (Sheffield Hallam), review of tennis racket performance parametersopened, quote confirmedimpact 3 to 5 ms; grip force unrelated to rebound speed; e_A about 0.4 at 280 N rising about 7 percent at 224 N; swingweight 0.030 to 0.035 kg m^2 band; 15 percent energy lost in the ball vs 2 to 4 percent in strings
• S23Cross, Effects of string tension and ball dynamicsopened, quote confirmedclamped vs hand-held restitution; incoming-speed dependence; ball as the main energy sink
• S26Cross, Measurements of the speed and bounce of tennis courtsopened, quote confirmedITF classes by COF and COR; Pace = 100(1 - mu) when sliding throughout; mu < 0.77 slides throughout the standard test; COF falls above about 15 degrees incidence

Read a court by its two numbers, friction and restitution, not by its name: the same stroke lands a different bounce on each, and a heavy topspin ball sits up only where incoming vertical speed and court restitution allow. Treat 'the ball kicked sideways' as a spin-axis and friction claim to test, not as a property of sidespin.

The bounce law is the cleanest physics in the vector: the ITF 2026 booklet confirmed the court pace formula and test conditions, the Cross American Journal of Physics paper confirmed the horizontal restitution range from negative to positive, and the Cross speed-and-bounce paper confirmed the friction and restitution class thresholds. It fell only because it also cites the impulse page that lacks the angular identity. The page may say a court is read by two numbers, friction and restitution, and that a ball can leave the bounce spinning faster than rolling because the court returns tangential energy; the folk picture of topspin kicking up on its own is bounded.

Across the opened stroke studies, no single joint or timing deviation is established as the dominant cause of lost racket speed, ball speed or spin across stroke families and skill levels; a dominant error can be named only after the output, stroke, incoming ball, impact point, equipment and measurement model are fixed (S2, S9, S15, S27, S28). Segment 'contribution' percentages are kinematic projections of a velocity field onto racket-head velocity, not energy or impulse shares: in 11 players' power serves, internal rotation contributed 54.2 percent, hand flexion 31.0 percent, horizontal flexion 12.9 percent, shoulder linear velocity 9.7 percent and forearm extension -14.4 percent of forward racket velocity (S27, CORRELATIONAL kinematics), and the method's authors state the contribution depends on both the segment's angular velocity and the racket's instantaneous position relative to its axis, with pronation fastest at impact (24 rad/s) yet ranked fourth at 4 m/s (S28); in elite forehands measured by IMU, upper-arm horizontal flexion accounted for about 45 to 48 percent, forearm extension 17 to 21 percent and internal rotation 14 to 16 percent of modeled anteroposterior racket velocity (S16). Percentages that exceed 100 percent with a negative member cannot be additive sources. Across skill, six ATP professionals against seven high-performance players showed later peak pelvis (-0.075 +/- 0.008 vs -0.093 +/- 0.012 s before impact) and trunk angular velocity (-0.057 +/- 0.004 vs -0.075 +/- 0.011 s; p < 0.01) with a tendency to higher racket speed (33.1 +/- 2.4 vs 31.1 +/- 1.9 m/s; p < 0.05) and similar peak angular velocities (S9, CORRELATIONAL, 400 Hz, fastest successful shots selected). In 36 competitive servers the time between peak vertical and peak anteroposterior ground force (r = -0.519) and between peak anteroposterior force and impact (r = -0.522) were the best predictors of maximal racket velocity, while mean and peak vertical ground force and its rate of development did not correlate (S15, CORRELATIONAL, two force plates); in nine players three peak ground-force components jointly explained 37 percent of ball-speed variance at prescribed effort levels, which is a share of variance, not of energy (S8); a greater knee-flexion group gained +130.3 deg/s knee extension and +3.33 km/h (about 0.93 m/s, about 3 percent) of racket velocity (S32). None of these is a perturbation study: no study constrained a segment and measured the racket-speed consequence, so causal contribution remains an inference from coordination. Population: touring and competitive men, elite forehands, 400 to 480 Hz laboratory capture; outcome: racket-head and ball speed; evidence class: CORRELATIONAL throughout.

Racket contact-point velocity is v_C = J_C(q) q', a sum of angular-velocity vectors with configuration-dependent lever arms, so a joint can create racket speed early in the swing without a large instantaneous geometric share at contact, and vice versa (S2). The question 'what caused the loss' requires a counterfactual map from torque history to the contact state, which only an intervention or a validated forward-dynamics model supplies; peak-order timing identifies neither.

Granted tier: SIGNAL, set by the code gate on October 4, 2026 (the writer claimed FORGED) · Refuted by the adversary on a claim no opened source could verify · Sources: 9 cited, 3 opened and confirmed

• VECTOR KILL: 3 misquote flag(s) in this vector (>= 2) -> SIGNAL for every axiom in it
• CLAMPED: claimed FORGED -> granted SIGNAL (gate lowers, never raises)

S2 (Koike & Harada 2013), S27 (Elliott, Marshall & Noffal 1995), S28 (Sprigings et al. 1994), S16 (Pedro et al. 2022), S9 (Landlinger et al. 2010), S15 (Fourel et al. 2024), S8 (Shimokawa et al. 2020), S32 (knee-flexion serve study), S33 (table tennis named limit). openai-dr opened S2, S8, S9; exa opened S9, S15, S16; anthropic cited S27, S28, S32, S33 as extracts. Dates: 1994 to 2024; fetched 2026-10-04.

• S2Koike & Harada 2013, JSME Symposium on Sports Engineering (dynamic contribution formulation)opened, quote confirmedmotion-dependent terms separated from joint torque; a kinematic contribution is not a causal one
• S8Shimokawa et al. 2020, ground reaction forces and forehand ball speeddid not open9 players; three peak GRF components jointly explained 37 percent of ball-speed variance
• S9Landlinger et al. 2010, JSSM 9:643-651, forehand of different skill levelsopened, quote confirmed6 ATP professionals vs 7 high-performance players, 400 Hz: pelvis and trunk peak timing differ, racket speed 33.1 vs 31.1 m/s
• S15Fourel et al. 2024, J Strength Cond Res 38(9):1667-1674, force-time curve variables and serve performancedid not open36 competitive players, two force plates: GRF timing intervals r = -0.519 and -0.522 best predictors of racket velocity; peak vertical GRF not correlated
• S16Pedro et al. 2022, Sensors 22:1283, IMU upper-limb joint contribution to racket head speed (elite forehand)did not openupper-arm horizontal flexion about 45 to 48 percent, forearm extension 17 to 21, internal rotation 14 to 16 percent of modeled anteroposterior racket velocity
• S27Elliott, Marshall & Noffal 1995, contributions of upper-limb segment rotations in the power servedid not open11 players: internal rotation 54.2 percent, hand flexion 31.0, horizontal flexion 12.9, shoulder linear 9.7, forearm extension -14.4 percent of racket velocity
• S28Sprigings et al. 1994, three-dimensional kinematic method for arm segment rotations and racquet-head speeddid not opencontribution depends on segment angular velocity and racquet position; internal rotation 8 m/s greatest, pronation 24 rad/s but fourth at 4 m/s
• S32Knee flexion and serve racket velocity (PMC 2024)opened, quote confirmedgreater knee-flexion group: +130.3 deg/s knee extension speed and +3.33 km/h racket velocity
• S33Iino & Kojima, kinematics of table tennis topspin forehands by performance leveldid not openadvanced players: larger lower-trunk rotation contribution and steeper racket acceleration, racket speed at impact not different (named limit: table tennis)

Diagnose a stroke at the contact state (racket speed, face angle, impact point) and at the ground-force timing intervals that correlate with racket speed, never from a segment-contribution percentage or the order of velocity peaks; a coaching claim that one segment or one timing error is 'the' leak is a hypothesis to test under a matched feed, not a law.

The non-dominance law is the run's answer to the adjacent article's kinetic-chain story and to the saying that it is all in the footwork, and it is also the least verified axiom in the stroke contact flight and bounce vector: the Landlinger elite-versus-high-performance timing figures and the knee-flexion gain were confirmed, but the Fourel force-timing correlations, the Elliott serve percentages with their negative elbow term, the Sprigings ranking and the Pedro IMU shares all sit on pages that would not open. The structural point survives on logic alone (segment percentages are projections of one velocity field, and no perturbation study exists), so the page may say that no single segment or timing error is established as the universal leak and that force timing rather than peak force tracks racket speed, and must hold the specific percentages as unverified.

Serves, drives, slices, volleys and drop shots differ in the incoming ball state, contact height, reachable racket configurations and the three-dimensional spin axis they set, not in the physics that maps the contact state to the ball (S1, S4, S7). In seven male players serving with marked balls at 500 Hz, mean forward ball speeds were about 51, 46 and 40 m/s for flat, slice and kick serves with spins of about 1240, 2300 and 3400 rpm, no flat serve was spin-free and the spin axes differed (S7, CORRELATIONAL, descriptive; the attached markers modified the measured ball). In 37 experienced and recreational adults, a commercial handle sensor reported topspin forehands at about 111 against 94 km/h and 2130 against 1590 rpm by group, with the instrumented rackets weighing about 376 g and spin inferred from handle motion rather than observed ball rotation (S11, CORRELATIONAL, device-inferred). A blocked return or volley can take most of its outgoing speed from the incoming ball, so a short racket motion is not a small ball impulse; a drop shot lowers outgoing speed by lowering relative normal speed or letting the racket recoil, with spin and direction remaining separate quantities (S1, S4, S24, MODEL deductions). The coverage gap is itself a finding: the opened joint-level studies measure touring professionals, competitive and collegiate men and elite forehands or serves; slice backhands, one- and two-handed backhand drives, volleys, drop shots, overheads, kick-serve spin-axis mechanics, women in contribution studies and adult recreational players are effectively unstudied at the segment level (S9, S10, S16, S27), and the professional tracking set covers flight, not body mechanics (S12). So any finding from a professional or collegiate population is a finding about that population until a source shows it transfers. Claimed PROBABLE because the stroke-family measurements rest on one small serve study and one device-inferred adult study.

The same impulse map (normal channel for speed, tangential channel for spin and launch direction) applies to every stroke; what changes is the input state: incoming velocity and spin, contact height, available swing path and time, and the achievable face orientation. Two hands on the handle add a force couple and a closed-loop constraint, slice reverses the tangential impulse sign, and a toss removes most incoming horizontal momentum.

Granted tier: SIGNAL, set by the code gate on October 4, 2026 (the writer claimed PROBABLE) · Refuted by the adversary on a source said less than the claim · Sources: 10 cited, 5 opened and confirmed

• TRIPWIRE: this axiom's own source(s) S1 (number_not_on_page), S24 (number_not_on_page) were wrong -> SIGNAL (the tripwire hits the axiom whose use of a source was wrong)
• CLAMPED: claimed PROBABLE -> granted SIGNAL (gate lowers, never raises)

S7 (Sakurai 2007 serve speeds and spins), S11 (Rigozzi 2023 recreational and experienced adults, sensor-inferred), S4 and S1 (collision law common to strokes), S24 (effective mass and recoil for blocked shots), S9, S10, S16, S27 (populations measured: ATP, high-performance, collegiate men, elite), S12 (tracking covers flight). openai-dr opened S7 and S11 and listed the omitted strokes; anthropic listed the unstudied strokes and the absent adult recreational population; exa and gemini-dr noted lab data omit defensive lunges and sliced backhands. Dates: S7 2007, S11 2023, S12 2026; fetched 2026-10-04.

• S1OpenStax University Physics vol. 1, 9.2 Impulse and Collisionsopened, the number was not on the pagelinear and angular impulse identities; internal forces cancel in the whole-system momentum balance
• S4Cross, Oblique impact of a tennis ball on the strings of a tennis racketopened, quote confirmedball slides, grips, then releases during one impact; court grip above about 20 degrees incidence; horizontal speed roughly halves after a gripping zero-spin bounce
• S7Sakurai et al. 2007, ISB congress, ball spin in flat, slice and kick servesopened, quote confirmed7 male players, 500 Hz: forward speeds about 51/46/40 m/s and spins about 1240/2300/3400 rpm; no flat serve spin-free
• S9Landlinger et al. 2010, JSSM 9:643-651, forehand of different skill levelsopened, quote confirmed6 ATP professionals vs 7 high-performance players, 400 Hz: pelvis and trunk peak timing differ, racket speed 33.1 vs 31.1 m/s
• S10Kwon et al. 2017, racquet kinematics and topspin angular velocityopened, quote confirmed13 male collegiate players: face angle and vertical racket velocity predicted topspin; path angle alone not significant
• S11Rigozzi et al. 2023, Sensors 23:5146, flat vs topspin forehands in experienced and recreational adultsopened, quote confirmed37 adults, handle sensor: about 111 vs 94 km/h and 2130 vs 1590 rpm; sensor-inferred spin, 376 g instrumented rackets
• S12Eassom, Robertson & Reid 2026, Sports Engineering, tennis ball trajectory decomposition from tracking datadid not open8,654 serves, 2022 Australian Open: median fit residuals 4.8 mm before and 2.4 mm after bounce; spin inferred via aerodynamic model
• S16Pedro et al. 2022, Sensors 22:1283, IMU upper-limb joint contribution to racket head speed (elite forehand)did not openupper-arm horizontal flexion about 45 to 48 percent, forearm extension 17 to 21, internal rotation 14 to 16 percent of modeled anteroposterior racket velocity
• S24Cross & Lindsey, TWU racquet power (effective mass and ACOR by impact point)opened, the number was not on the pagehand-held perpendicular speed ratio 0.1 to 0.5 by impact point vs about 0.85 clamped
• S27Elliott, Marshall & Noffal 1995, contributions of upper-limb segment rotations in the power servedid not open11 players: internal rotation 54.2 percent, hand flexion 31.0, horizontal flexion 12.9, shoulder linear 9.7, forearm extension -14.4 percent of racket velocity

For the rebuilding a stroke vector and the page: a mechanism measured on professionals or collegiate men is carried to an adult club player as a hypothesis with the population named, and a claim about a slice backhand, volley or drop shot has no joint-level evidence behind it at all; the honest page says which strokes the physics has been measured on and which it has only been derived for.

The population law is the one the stroke contact flight and bounce vector finding the page most needs: the Sakurai serve speeds and spins and the Rigozzi recreational-adult sensor study were confirmed, and together with the roster of opened studies they show that the measured joint-level physics covers serves and forehands in touring professionals and collegiate men, with slice backhands, volleys, drop shots, overheads, women and adult club players effectively unstudied at the segment level. So the page's phrase about deconstructing every stroke to its physics is, for most of his strokes, derivation from one collision law rather than measurement, and the honest page says which strokes the physics has been measured on.

In adults changing a motor pattern, three outcomes must be measured separately because each can move without the others: (1) acquisition, the movement and result produced during a practice session with the coach, the cue and the feed present; (2) retention, the same movement produced after a delay of at least 24 hours and ideally a week or more, with no reminder, no video and no coach; (3) transfer, the retained movement produced under representative conditions, a live opponent, variable balls, time pressure and a score. Observation: in Soderstrom and Bjork's 2015 review of the laboratory and classroom literature (CORRELATIONAL and INTERVENTION studies across adults), considerable learning occurred without performance gains during practice and substantial practice gains failed to appear at delayed tests; in Shea and Morgan 1979 (72 college students, INTERVENTION, 10-minute and 10-day retention) the group that looked better during acquisition retained and transferred worse. Observation in tennis: Buszard, Reid, Krause, Kovalchik and Farrow 2017 (INTERVENTION, 16 skilled youth tennis players, 10 serve-practice sessions, tests one week before and one week after) found no practice-performance difference between groups, yet the moderate-interference group improved serve displacement from the T only in the match-play transfer test and the low-interference group improved only in the closed skill test. Inference: a closed test and a match test estimate different quantities, so a stroke judged on one has not been judged on the other. Boundary: the dissociation is documented in laboratory adults, college students and skilled juniors; the Buszard effect sizes are from 16 juniors and are the only tennis-specific measurement opened; no leg opened a delayed, uncued, representative test of a prescribed stroke change in experienced adult club players.

Learning is a change in the stored capability to produce a movement; performance is the movement produced now under present support. Present support (a cue, a feed, a coach, a predictable ball) raises performance without changing the stored capability, and the stored capability can rise while effortful practice lowers today's performance. A measurement taken while the support is present estimates the sum of capability and support and cannot separate them; a delayed uncued test removes the support term; a representative test adds the match's own perturbations. The three estimands differ in what is held constant, so one number cannot stand for another.

Granted tier: PROBABLE, set by the code gate on October 4, 2026 (the writer claimed FORGED) · Survived the adversary's attack · Sources: 5 cited, 4 opened and confirmed

• PROBATION: 1 misquote flag elsewhere in this vector (below the kill line of 2); this axiom's own sources were clean -> capped at PROBABLE
• survived a grounded cross-lab adversary (google vs authors ["anthropic"])
• citations: refetched 88% (>=90%), resolved 96% (>=80%) -> BELOW FLOOR
• dead links: 4 of 32 source(s) would not open, a miss counted in the ratio above, never a misquote
• EARNED PROBABLE: one of {grounded cross-lab adversary, verified sources} but not both
• CLAMPED: claimed FORGED -> granted PROBABLE (gate lowers, never raises)

S1 (learning versus performance dissociation, review), S24 (acquisition versus 10-day retention and transfer, 72 students), S2 (closed skill test versus match-play transfer dissociate in 16 skilled youth tennis players), S26 (feedback helps practice, hurts retention), S25 (retention at 4 weeks tracks distribution across days, not amount).

• S1Soderstrom & Bjork 2015, Learning Versus Performance: An Integrative Review (Perspectives on Psychological Science)opened, quote confirmedperformance during practice is an unreliable index of learning; learning is inferred only from delayed retention and transfer
• S24Shea & Morgan 1979, Contextual interference effects on the acquisition, retention, and transfer of a motor skill (Journal of Experimental Psychology: Human Learning and Memory)opened, quote confirmed72 college students, three tasks: blocked practice looked better during acquisition; random practice retained better at 10 minutes and 10 days under changed conditions and transferred better
• S2Buszard, Reid, Krause, Kovalchik & Farrow 2017, Quantifying Contextual Interference and Its Effect on Skill Transfer in Skilled Youth Tennis Players (Frontiers in Psychology 8:1931)opened, quote confirmed16 skilled youth tennis players, 10 serve sessions: moderate CI improved match-play transfer but not the closed skill test; low CI the reverse; no practice-performance difference
• S26Winstein & Schmidt 1990, Reduced frequency of knowledge of results enhances motor skill learning (Journal of Experimental Psychology: Learning, Memory, and Cognition)did not openreduced or faded knowledge of results improved delayed retention relative to feedback after every trial although frequent feedback helped during practice
• S25Savion-Lemieux & Penhune 2005, The effects of practice and delay on motor skill learning and retention (Experimental Brain Research 161:423)opened, quote confirmedamount of practice per se did not change 4-week retention of a timed motor sequence; distribution of practice over several days did

A rebuilt stroke counts as rebuilt only when its kinematics appear on an uncued test a week or more later and again under a live opponent; a clean session on the ball machine is non-diagnostic. The page may describe the rebuild as a process but may not report it as achieved until those two tests are on record.

The three-test law is the hinge of the rebuild verdict: acquisition, delayed uncued retention and live-opponent transfer are three estimands, and the one tennis intervention opened (skilled juniors on the serve) moved a closed test and a match test in opposite directions. The gate held it one rung below the claim because another axiom in this vector cited a page that showed only metadata; its own sources were clean. For the page this is the sentence that converts a profile card into an investigation: the rebuild may be described as a process and may be reported as achieved only when a changed stroke appears a week or more later without a coach and again under a live opponent.

In adults who adapt a movement and then train an opposing one, the first pattern is not erased. Observation (INTERVENTION with MODEL fit, healthy young adults in laboratory reaching tasks): Smith, Ghazizadeh and Shadmehr 2006 showed that after adaptation followed by counter-adaptation, clamping errors produced spontaneous recovery, a rebound toward the first pattern, which a two-process model reproduces: a fast process that responds strongly to error but decays quickly and a slow process that responds weakly but retains; the slow process is also initially biased against the second adaptation (anterograde interference). Kitago, Ryan, Mazzoni, Krakauer and Haith 2013 (INTERVENTION, adults, visuomotor rotation) compared washout by error clamp, by removing feedback, by removing the perturbation and by passage of time: time alone produced partial and inconsistent unlearning, every method left savings on re-exposure, and the authors describe unlearning as reversion to habit without forgetting. Szegedi-Hallgató et al 2017 (INTERVENTION, adults, a changed statistical regularity) found proactive interference from the old regularity, consolidation-dependent gains for the new one, and both old and new knowledge accessible afterwards. Avraham et al 2021 (INTERVENTION, adults) found that faster relearning is carried by explicit re-aiming while implicit adaptation is attenuated, so faster reacquisition is not a sign the old memory is gone. Inference: a tennis stroke hit for years is a slow-process memory; its behavioral disappearance in practice is evidence about present expression, never about storage. Boundary: every measurement is from laboratory adaptation and sequence tasks over minutes to days in young adults; the extension to a years-old stroke in an adult club player is a mechanism inference the legs agree on and no tennis study tests.

Motor memory is multi-rate. The fast component carries most of the behavior early in a change and decays within minutes to days without error feedback; the slow component carries the long-practiced pattern, changes little per trial, and retains across months. Training a new pattern drives the fast component and only slowly moves the slow one, so when the fast component decays or is stripped of feedback the slow component's output, the old stroke, is what remains. Savings and spontaneous recovery are the two signatures a pure overwriting system cannot produce and a multi-rate system must.

Granted tier: PROBABLE, set by the code gate on October 4, 2026 (the writer claimed FORGED) · Survived the adversary's attack · Sources: 5 cited, 5 opened and confirmed

• PROBATION: 1 misquote flag elsewhere in this vector (below the kill line of 2); this axiom's own sources were clean -> capped at PROBABLE
• survived a grounded cross-lab adversary (google vs authors ["anthropic"])
• citations: refetched 88% (>=90%), resolved 96% (>=80%) -> BELOW FLOOR
• dead links: 4 of 32 source(s) would not open, a miss counted in the ratio above, never a misquote
• EARNED PROBABLE: one of {grounded cross-lab adversary, verified sources} but not both
• CLAMPED: claimed FORGED -> granted PROBABLE (gate lowers, never raises)

S3 (two-rate model, spontaneous recovery, anterograde interference), S4 (unlearning as reversion to habit, savings after every washout), S5 (old and new regularities coexist, proactive interference), S6 (savings are explicit, implicit adaptation attenuates on relearning), S8 (two opposing adaptations retained in parallel).

• S3Smith, Ghazizadeh & Shadmehr 2006, Interacting Adaptive Processes with Different Timescales Underlie Short-Term Motor Learning (PLoS Biology)opened, quote confirmeda fast error-sensitive poorly-retaining process plus a slow error-insensitive well-retaining process predict savings, spontaneous recovery and anterograde interference
• S4Kitago, Ryan, Mazzoni, Krakauer & Haith 2013, Unlearning versus savings in visuomotor adaptation (Frontiers in Human Neuroscience)opened, quote confirmedunlearning behaves as reversion to habit rather than forgetting; time alone gives partial inconsistent unlearning; savings persist after every washout method
• S5Szegedi-Hallgató et al 2017, Explicit instructions and consolidation promote rewiring of automatic behaviors in the human mind (Scientific Reports)opened, quote confirmedrewiring a learned regularity shows proactive interference from the old one, consolidation-dependent gains for the new one, and both remain accessible
• S6Avraham, Morehead, Kim & Ivry 2021, Reexposure to a sensorimotor perturbation produces opposite effects on explicit and implicit learning processes (PLoS Biology)opened, quote confirmedsavings on re-exposure is carried by explicit re-aiming while implicit adaptation is attenuated; faster relearning is not evidence of erasure
• S8Lee & Schweighofer 2009, Dual Adaptation Supports a Parallel Architecture of Motor Memory (Journal of Neuroscience)opened, quote confirmedtwo opposing adaptations are retained together when slow states are indexed by contextual cues; a single two-state memory cannot hold both

The player should expect the old stroke to reappear after a layoff, when feedback stops, and when attention is taken, and should read that reappearance as the memory architecture working, not as the rebuild having failed; the test that discriminates is whether the new stroke also re-establishes faster than it did the first time.

The non-erasure law refutes the folk sense of muscle memory as overwriting: a years-old stroke is a slow, well-retained memory, training adds a competitor, and savings and spontaneous recovery are the two signatures an overwriting system cannot produce. Every opened source is laboratory adaptation in young adults, and the extension to a club player's forehand is an agreed mechanism inference. The page may say the old stroke never leaves and waits for the cues that built it; the useful self-test is whether, after a layoff, the new stroke also re-establishes faster than it did the first time.

When an adult holds two motor patterns for the same task, the pattern expressed on a given trial is selected by contextual cues present at retrieval. Observation (INTERVENTION with MODEL fit, healthy adults in reaching tasks): Lee and Schweighofer 2009 showed that two opposing adaptations are retained together only when slow memory states are indexed by contextual cues, which a single two-state memory cannot do; Heald, Lengyel and Wolpert 2021 showed across sensorimotor experiments that much apparent learning and forgetting is a change in which existing memory is expressed, driven by inferred context, rather than a change in the memory itself. Proteau, Marteniuk and Lévesque 1992 (INTERVENTION, adults, aiming) found learning specific to the sensory information available in practice, with performance falling when a practiced information source was withdrawn even after extended practice. Observation in tennis (INTERVENTION, 16 skilled youth players): in Buszard et al 2017 the serve improvement appeared in the test whose conditions matched the practice conditions, closed for low-interference practice and match-play for moderate-interference practice. Inference: a stroke rebuilt against a basket feed, a flat trajectory, a coach's voice and no score is indexed to that cue set; a match presents a different cue set in which the old stroke holds the index, so transfer failure is a retrieval failure and more repetitions in the practice context deepen the practice index. Boundary: the mechanism is measured in laboratory adults and modeled; the tennis observation is one study of 16 juniors on the serve; no leg opened a study that recorded which stroke pattern an experienced adult produced across practice and match within the same period.

Memory retrieval is a selection problem. The nervous system holds several candidate motor memories for one action and infers from present cues, ball flight, opponent position, score, fatigue, the coach's presence, which context it is in and so which memory to express. Repetition strengthens a memory and strengthens its binding to the cues present when it was practiced; it does not rebind it to cues that were absent. A match supplies cues bound for years to the old stroke, so the old stroke wins selection there until the new stroke has been practiced under those cues.

Granted tier: PROBABLE, set by the code gate on October 4, 2026 · Survived the adversary's attack · Sources: 5 cited, 5 opened and confirmed

• PROBATION: 1 misquote flag elsewhere in this vector (below the kill line of 2); this axiom's own sources were clean -> capped at PROBABLE
• survived a grounded cross-lab adversary (google vs authors ["anthropic"])
• citations: refetched 88% (>=90%), resolved 96% (>=80%) -> BELOW FLOOR
• dead links: 4 of 32 source(s) would not open, a miss counted in the ratio above, never a misquote
• EARNED PROBABLE: one of {grounded cross-lab adversary, verified sources} but not both

S8 (cue-indexed slow states hold two adaptations), S7 (contextual inference selects which memory is expressed), S9 (specificity of practice to the information available), S2 (improvement appears in the test matching the practice context), S5 (both old and new knowledge remain available).

• S8Lee & Schweighofer 2009, Dual Adaptation Supports a Parallel Architecture of Motor Memory (Journal of Neuroscience)opened, quote confirmedtwo opposing adaptations are retained together when slow states are indexed by contextual cues; a single two-state memory cannot hold both
• S7Heald, Lengyel & Wolpert 2021, Contextual inference underlies the learning of sensorimotor repertoires (Nature)opened, quote confirmedbehavior change can be a change in which existing motor memory is expressed, selected by inferred context, rather than a change in the memory itself
• S9Proteau, Marteniuk & Lévesque 1992, A Sensorimotor Basis for Motor Learning: Evidence Indicating Specificity of Practice (Quarterly Journal of Experimental Psychology)opened, quote confirmedlearning is specific to the sensory information available during practice; removing a practiced information source degrades performance even after extended practice
• S2Buszard, Reid, Krause, Kovalchik & Farrow 2017, Quantifying Contextual Interference and Its Effect on Skill Transfer in Skilled Youth Tennis Players (Frontiers in Psychology 8:1931)opened, quote confirmed16 skilled youth tennis players, 10 serve sessions: moderate CI improved match-play transfer but not the closed skill test; low CI the reverse; no practice-performance difference
• S5Szegedi-Hallgató et al 2017, Explicit instructions and consolidation promote rewiring of automatic behaviors in the human mind (Scientific Reports)opened, quote confirmedrewiring a learned regularity shows proactive interference from the old one, consolidation-dependent gains for the new one, and both remain accessible

The practice that transfers is the practice that carries the match's cues, a live opponent, variable balls, consequence; a rebuilt stroke that works only off a feed has been indexed to the feed, and the fix is to change the practice context, not to add repetitions in it.

The cue-indexed retrieval law explains why a rebuilt stroke that works off a feed fails in a match without anything being wrong with the stroke: which of two held patterns is expressed is selected by present context, and repetition strengthens a pattern's binding to the cues present when it was practiced. The tennis observation is the same sixteen-junior serve study, so the mechanism is laboratory and the tennis instance is one small sample. For the player the implication is to change the practice context (live opponent, variable balls, a score) rather than add repetitions in the feed context.

Observation (INTERVENTION, 42 adults): Sperl, Gergeleit and Cañal-Bruland 2021 exchanged two letters on a familiar keyboard mapping; speed fell and errors rose immediately, participants who performed better on the old mapping were disrupted more on the new one, and measures of response inhibition predicted parts of the disruption. Observation (CORRELATIONAL case series, three elite golfers): Carson and Collins 2015 tracked established-technique changes with kinematics, intra-individual variability and rated mental effort; the authors' generalization across levels is that the more experienced and overlearned the execution, the more difficult it is to change, and their 2011 framework applies the same refinement procedures to a recreational adult golfer on the basis of movement automaticity rather than skill level. Inference: an adult who has hit one forehand for years is proficient at that forehand and a novice at selecting against it; the experienced player's advantage in the old pattern is a liability in the change, paid through inhibition. Boundary: the direct measurement is a keyboard task in 42 adults over one session; the sport evidence is a three-case series in elite golfers; no leg opened a study scaling change cost against years of tennis practice.

An automated pattern is retrieved with little attention and strong cue binding. Producing a different pattern to the same cue requires suppressing the automatic retrieval before the new pattern can be issued, so the change runs through the inhibition system on every trial until the new binding dominates. The stronger and faster the old retrieval, the more inhibition each trial costs and the more often inhibition fails under load, which is why proficiency in the old pattern predicts larger disruption during the change.

Granted tier: SIGNAL, set by the code gate on October 4, 2026 (the writer claimed PROBABLE) · Survived the adversary's attack · Sources: 3 cited, 2 opened and confirmed

• TRIPWIRE: this axiom's own source(s) S11 (number_not_on_page) were wrong -> SIGNAL (the tripwire hits the axiom whose use of a source was wrong)
• CLAMPED: claimed PROBABLE -> granted SIGNAL (gate lowers, never raises)

S10 (better old performance predicts larger disruption; inhibition predicts it; 42 adults), S12 (the more overlearned the harder to change; three elite golfers), S11 (refinement procedures keyed to automaticity, applied to a recreational adult).

• S10Sperl, Gergeleit & Cañal-Bruland 2021, On the role of different subdimensions of inhibition for successful motor skill change (Human Movement Science)opened, quote confirmed42 adults, a swapped keyboard mapping: better performance on the old mapping predicted larger disruption on the new one; response-inhibition measures predicted the disruption
• S12Carson & Collins 2015, Tracking Technical Refinement in Elite Performers: The Good, the Better, and the Ugly (International Journal of Golf Science)opened, quote confirmedthree elite golfers changing an established technique: kinematic change and reduced conscious control came apart; one achieved the change without reduced mental effort, one both, one neither; the more overlearned the execution, the harder the change
• S11Carson & Collins 2011, Refining and regaining skills in fixation/diversification stage performers: the Five-A Model (International Review of Sport and Exercise Psychology)opened, the number was not on the pagetechnical refinement in already-automated performers is a different problem from acquisition; the model proposes Analysis, Awareness, Adjustment, Re-automation, Assurance; testing against implicit motor learning is still required

The player should price each stroke change by how automatic the old stroke is, not by how far the new target is from it; the strokes he has hit longest will cost most to change and will fail most under load, and that cost is the budget the rebuild must carry.

The entrenchment law prices each stroke change by the automaticity of the incumbent: the keyboard-remapping study confirmed that better old performance predicted larger disruption and that inhibition measures predicted it. The golf case-series page returned only title and metadata, so the quoted generalisation that the more overlearned the execution the harder the change is unverified in this run, and that is why the gate pulled the axiom to the bottom rung. The usable form for the page: the strokes he has hit longest will cost most to change and will fail first under load.

To change an automated movement an adult must attend to it explicitly; explicit control is the control mode that breaks under pressure, so a changed stroke is pressure-fragile by construction until it is re-automated. Observation: Masters and Maxwell 2008 (review of INTERVENTION studies) describe reinvestment, in which anxiety leads a performer to control a movement with explicit rules, consuming working memory and disrupting automatic execution. Liao and Masters 2001 (INTERVENTION, table tennis novices) found analogy learners accumulated fewer explicit rules and were less impaired by a secondary task; Lam, Maxwell and Masters 2009 (INTERVENTION, novices) found the explicit group fell on a pressured transfer test while the analogy group did not. Cabral, Wilson and Miller 2022 (meta-analysis of 10 INTERVENTION studies, median 9 participants per group) found implicit learners performed better under high than low pressure, Hedges g_av -1.17 (95 percent CI -1.61 to -0.74), while comparison groups did not differ, and flagged publication bias and underpowering. Bounds: Kal et al 2018 (systematic review) found most implicit-versus-explicit comparisons showed no automaticity difference on low-quality evidence; Koedijker, Oudejans and Beek 2008 (INTERVENTION, 10,000 forehands over six weekly sessions) found the rule gap narrowed from 1,400 to 10,000 repetitions and no retention difference; Collins, MacPherson, Bobrownicki and Carson 2023 argue explicit awareness has a role in refining an established skill; Wulf and Su 2007 (INTERVENTION, expert golfers) found the control condition performed like internal focus while external focus still improved accuracy. Carson and Collins 2015 (three elite golfers) found kinematic change and reduced mental effort came apart, one golfer changing the movement without reducing conscious control. Inference: the debt is real and is paid down by re-automation; its size, not the instruction style alone, sets the stroke's fragility. Boundary: the pressure evidence is from novices in small samples; the refinement evidence is three cases; the pressure increment itself is the skill under pressure vector's.

Automatic execution runs outside working memory; a changed component is assembled under working-memory control until its new binding is strong enough to run without it. Pressure draws attention inward and loads working memory, so a component that still depends on working memory loses its controller exactly when the match raises the stakes, while a fully automated component is unaffected. The fragility is a property of how much of the stroke still runs explicitly, which is why reducing declarative content and re-automating both reduce it.

Granted tier: PROBABLE, set by the code gate on October 4, 2026 · Survived the adversary's attack · Sources: 9 cited, 6 opened and confirmed

• PROBATION: 1 misquote flag elsewhere in this vector (below the kill line of 2); this axiom's own sources were clean -> capped at PROBABLE
• survived a grounded cross-lab adversary (google vs authors ["anthropic"])
• citations: refetched 88% (>=90%), resolved 96% (>=80%) -> BELOW FLOOR
• dead links: 4 of 32 source(s) would not open, a miss counted in the ratio above, never a misquote
• EARNED PROBABLE: one of {grounded cross-lab adversary, verified sources} but not both

S13 (reinvestment theory), S14 (fewer rules, less dual-task impairment, novices), S15 (explicit group falls under pressure, analogy group does not), S16 (meta-analysis g_av -1.17, 10 studies, bias flagged), S17 (most comparisons show no automaticity difference), S30 (rule gap narrows and retention equal at 10,000 repetitions), S18 (explicit awareness has a role in refinement), S19 (external focus helps experts), S12 (movement change and conscious control dissociate).

• S13Masters & Maxwell 2008, The theory of reinvestment (International Review of Sport and Exercise Psychology)did not openunder pressure a performer reinvests explicit rule-based control in a movement, which consumes working memory and disrupts automatic execution
• S14Liao & Masters 2001, Analogy learning: a means to implicit motor learning (Journal of Sports Sciences)opened, quote confirmedtable tennis novices learning the forehand topspin by analogy accumulated fewer explicit rules than an explicit group and were less impaired by a concurrent secondary task
• S15Lam, Maxwell & Masters 2009, Analogy Learning and the Performance of Motor Skills under Pressure (Journal of Sport and Exercise Psychology)opened, quote confirmedthe explicit group's performance fell on a pressured transfer test relative to retention while the analogy group's did not; analogy learners reported less access to movement rules
• S16Cabral, Wilson & Miller 2022, The Effect of Implicit Learning on Motor Performance Under Psychological Pressure: A Systematic Review and Meta-Analysis (Sport, Exercise, and Performance Psychology)opened, quote confirmed10 studies, median 9 participants per group: implicit learners performed better under high than low pressure (Hedges g_av -1.17, 95 percent CI -1.61 to -0.74) while comparison groups did not differ; publication bias and underpowering flagged
• S17Kal, Prosée, Winters & van der Kamp 2018, Does implicit motor learning lead to greater automatization of motor skills compared to explicit motor learning? A systematic review (PLOS ONE)opened, quote confirmedmost implicit-versus-explicit comparisons found no difference in automaticity; the evidence base was judged low quality with unclear risk of bias
• S30Koedijker, Oudejans & Beek 2008, Table tennis performance following explicit and analogy learning over 10,000 repetitions (International Journal of Sport Psychology)did not openover 10,000 forehands across six weekly sessions explicit learners reported more rules than analogy learners, the gap narrowed from 1,400 to 10,000 repetitions, and the groups did not differ at retention
• S18Collins, MacPherson, Bobrownicki & Carson 2023, An Explicit Look at Implicit Learning: an Interrogative Review for Sport Coaching Research and Practice (Sports Coaching Review)opened, quote confirmedthe coaching-science case that implicit-learning superiority is overstated and that explicit awareness has a role in refining an established skill
• S19Wulf & Su 2007, An External Focus of Attention Enhances Golf Shot Accuracy in Beginners and Experts (Research Quarterly for Exercise and Sport)did not openin expert golfers the control condition performed about the same as internal focus; external focus still improved accuracy in practice and retention
• S12Carson & Collins 2015, Tracking Technical Refinement in Elite Performers: The Good, the Better, and the Ugly (International Journal of Golf Science)opened, quote confirmedthree elite golfers changing an established technique: kinematic change and reduced conscious control came apart; one achieved the change without reduced mental effort, one both, one neither; the more overlearned the execution, the harder the change

During a rebuild the player should expect the changed strokes to fail under pressure before they fail in practice, should treat rated mental effort on each stroke as the index of how much debt remains, and should hold the implicit-learning advantage as a small-sample finding in novices rather than a guarantee.

The explicit-control debt law is the learning-stage condition the skill under pressure vector's pressure laws need: a changed stroke component runs on working memory until re-automated, and working memory is what stakes tax. The implicit-learning advantage under pressure rests on a small-sample meta-analysis with flagged bias, and the automaticity review is null, so the axiom carries the debt mechanism as agreed and the instruction-style remedy as bounded. For the player, rated mental effort on each stroke is the index of how much debt remains, and a changed stroke should be expected to fail under pressure before it fails in practice.

Observation (meta-analyses of INTERVENTION studies): Brady 2004 pooled 139 effect sizes from 61 studies, mean effect .38 for random over blocked practice, .57 in basic research against .19 in applied research, .50 in adults against .10 in younger learners, no difference between retention and transfer outcomes, and mean study power .43. Czyż, Wójcik and Solarská 2024 pooled 34 studies on transfer: SMD 0.55 overall favoring random practice, 0.54 in adults, 1.28 in older adults, 0.12 in young participants, and smaller and nonsignificant in applied settings. Czyż et al 2024 pooled 54 studies on delayed retention: a medium benefit overall, almost negligible in applied settings, large in older adults, medium in adults, negligible and nonsignificant in young participants. Observation in skilled sport: Hall, Domingues and Cavazos 1994 (INTERVENTION, 30 college batters, six weeks, same extra dose) found random ordering of pitch types beat blocked ordering on both test formats; Buszard et al 2017 (INTERVENTION, 16 skilled youth tennis players) found moderate interference improved match-play serve transfer where low interference did not. Observation on spacing: Savion-Lemieux and Penhune 2005 (INTERVENTION, adults, timed motor sequence) found 4-week retention depended on distribution across days, not on one, three or six blocks of practice. Inference: the direction is robust and favors adults, the magnitude in applied sport is small, and session count across days governs weeks-long retention more than repetitions within a day. Boundary: every tennis-specific number is from 16 juniors on the serve; the adult effect sizes are from laboratory tasks; the applied estimates are near zero with wide uncertainty.

Interleaving forces the learner to reconstruct the movement plan on each trial instead of repeating a plan held in working memory, so each trial exercises retrieval, the operation a delayed test and a match demand; blocked repetition exercises execution of an already-loaded plan, which inflates acquisition and leaves retrieval untrained. Spacing across days lets consolidation run between exposures so each new day's retrieval starts from the consolidated state. In applied settings the task is already variable and noisy, which shrinks the added effect of a schedule.

Granted tier: PROBABLE, set by the code gate on October 4, 2026 (the writer claimed FORGED) · Survived the adversary's attack · Sources: 7 cited, 7 opened and confirmed

• PROBATION: 1 misquote flag elsewhere in this vector (below the kill line of 2); this axiom's own sources were clean -> capped at PROBABLE
• survived a grounded cross-lab adversary (google vs authors ["anthropic"])
• citations: refetched 88% (>=90%), resolved 96% (>=80%) -> BELOW FLOOR
• dead links: 4 of 32 source(s) would not open, a miss counted in the ratio above, never a misquote
• EARNED PROBABLE: one of {grounded cross-lab adversary, verified sources} but not both
• CLAMPED: claimed FORGED -> granted PROBABLE (gate lowers, never raises)

S20 (139 effect sizes, .38 overall, applied .19, adults .50), S21 (transfer SMD 0.55, adults 0.54, applied nonsignificant), S22 (retention medium, applied almost negligible), S23 (30 college batters, random beats blocked), S24 (the original dissociation), S2 (moderate interference transfers in 16 skilled juniors), S25 (distribution across days governs 4-week retention).

• S20Brady 2004, Contextual interference: a meta-analytic study (Perceptual and Motor Skills)opened, quote confirmed139 effect sizes from 61 studies: mean effect .38; basic research .57 versus applied .19; adults .50 versus younger learners .10; retention and transfer not different; mean study power .43
• S21Czyż, Wójcik & Solarská 2024, The effect of contextual interference on transfer in motor learning: a systematic review and meta-analysis (Frontiers in Psychology)opened, quote confirmed34 studies in the quantitative analysis: overall transfer effect SMD 0.55 favoring random practice; medium in adults (0.54), large in older adults (1.28), negligible in young participants (0.12); smaller and nonsignificant in applied settings
• S22Czyż et al 2024, High contextual interference improves retention in motor learning: systematic review and meta-analysis (Scientific Reports)opened, quote confirmed54 studies, delayed-retention results only: medium benefit of high CI overall; almost negligible in applied settings; large in older adults, medium in adults, negligible and nonsignificant in young participants
• S23Hall, Domingues & Cavazos 1994, Contextual Interference Effects with Skilled Baseball Players (Perceptual and Motor Skills)opened, quote confirmed30 skilled college batters, six weeks, same extra dose: random ordering of pitch types beat blocked ordering on both random and blocked post-tests
• S24Shea & Morgan 1979, Contextual interference effects on the acquisition, retention, and transfer of a motor skill (Journal of Experimental Psychology: Human Learning and Memory)opened, quote confirmed72 college students, three tasks: blocked practice looked better during acquisition; random practice retained better at 10 minutes and 10 days under changed conditions and transferred better
• S2Buszard, Reid, Krause, Kovalchik & Farrow 2017, Quantifying Contextual Interference and Its Effect on Skill Transfer in Skilled Youth Tennis Players (Frontiers in Psychology 8:1931)opened, quote confirmed16 skilled youth tennis players, 10 serve sessions: moderate CI improved match-play transfer but not the closed skill test; low CI the reverse; no practice-performance difference
• S25Savion-Lemieux & Penhune 2005, The effects of practice and delay on motor skill learning and retention (Experimental Brain Research 161:423)opened, quote confirmedamount of practice per se did not change 4-week retention of a timed motor sequence; distribution of practice over several days did

The player should spread stroke practice across days and mix strokes and ball types within a session rather than hitting one stroke in a block, and should expect the gain from that structure to be medium at most, not a lever that rebuilds a stroke by itself.

The practice-schedule law carries the pooled magnitudes the saying that practice makes perfect lacks: interleaving and spacing move adult retention and transfer by a medium amount in laboratory tasks, near zero in applied settings, and distribution across days governs weeks-long retention more than repetitions within a day. The same law appears in the anticipation and decision speed vector for perceptual training, which is why the two are grouped. For the page: schedule and spacing are a lever, not the lever, and the tennis-specific numbers are from juniors.

Observation: Winstein and Schmidt 1990 (INTERVENTION, adults) found that reducing or fading knowledge of results improved delayed retention although frequent feedback helped during practice, the finding behind the guidance hypothesis. Wulf, Chiviacowsky, Schiller and Ávila 2010 (INTERVENTION, adults) found feedback after every trial beat feedback after a third of trials on transfer when the feedback directed attention externally, so the content of feedback reversed the frequency result. McKay, Hussien, Carter, Yantha and Ste-Marie (2021 preprint, meta-analysis of 61 papers, k = 75, N = 2,228) found no significant effect of reduced feedback frequency at acquisition, immediate or delayed retention, substantial heterogeneity and a Z-curve indicating a severely underpowered literature. Proteau, Marteniuk and Lévesque 1992 (INTERVENTION, adults) found performance fell when a practiced information source was withdrawn even after extended practice. Inference: the general law survives, performance produced with a coach's cue, a video, a swing thought or a predictable feed does not license inference about performance without them, because it follows from the three-test law and cue-indexed retrieval; the specific quantitative prescription to reduce feedback frequency does not survive the pooled evidence. Boundary: all measurements are laboratory adults on simple tasks; no leg opened a feedback-schedule study in stroke change for experienced tennis players.

Augmented feedback and cues enter the control loop as an external error signal; while present they correct the next attempt without the learner's own error detection running. When the stroke is produced with that signal present, the learner's capability without it is unmeasured. Whether a given frequency builds dependence or builds learning depends on what information the feedback carries and where it points attention, which is why frequency alone has no pooled effect while content does.

Granted tier: PROBABLE, set by the code gate on October 4, 2026 · Survived the adversary's attack · Sources: 5 cited, 4 opened and confirmed

• PROBATION: 1 misquote flag elsewhere in this vector (below the kill line of 2); this axiom's own sources were clean -> capped at PROBABLE
• survived a grounded cross-lab adversary (google vs authors ["anthropic"])
• citations: refetched 88% (>=90%), resolved 96% (>=80%) -> BELOW FLOOR
• dead links: 4 of 32 source(s) would not open, a miss counted in the ratio above, never a misquote
• EARNED PROBABLE: one of {grounded cross-lab adversary, verified sources} but not both

S26 (reduced knowledge of results improves retention, the guidance finding), S27 (frequent external-focus feedback beats reduced, content reverses frequency), S28 (meta-analysis, 61 papers, N = 2,228, no frequency effect at any time point), S9 (withdrawing a practiced information source degrades performance), S1 (support inflates performance over learning).

• S26Winstein & Schmidt 1990, Reduced frequency of knowledge of results enhances motor skill learning (Journal of Experimental Psychology: Learning, Memory, and Cognition)did not openreduced or faded knowledge of results improved delayed retention relative to feedback after every trial although frequent feedback helped during practice
• S27Wulf, Chiviacowsky, Schiller & Ávila 2010, Frequent External-Focus Feedback Enhances Motor Learning (Frontiers in Psychology)opened, quote confirmedfeedback after every trial beat feedback after a third of trials on transfer when the feedback directed attention externally; the content of feedback changes the frequency result
• S28McKay, Hussien, Carter, Yantha & Ste-Marie 2021 preprint, Meta-analysis of reduced relative feedback frequency effect on motor learning and performance (PsyArXiv)opened, quote confirmed61 papers, k = 75, N = 2,228: no significant effect of reduced feedback frequency at acquisition, immediate or delayed retention; substantial heterogeneity; Z-curve shows the literature severely underpowered
• S9Proteau, Marteniuk & Lévesque 1992, A Sensorimotor Basis for Motor Learning: Evidence Indicating Specificity of Practice (Quarterly Journal of Experimental Psychology)opened, quote confirmedlearning is specific to the sensory information available during practice; removing a practiced information source degrades performance even after extended practice
• S1Soderstrom & Bjork 2015, Learning Versus Performance: An Integrative Review (Perspectives on Psychological Science)opened, quote confirmedperformance during practice is an unreliable index of learning; learning is inferred only from delayed retention and transfer

The coach's voice, the video and the ball feed are scaffolding; the player should schedule trials with every aid removed and read those trials as the measurement, and should not expect a rule about how often to hear feedback to carry the rebuild.

The support-removal law keeps the general principle and drops the specific coaching rule: every aid present when the new stroke is produced (coach's voice, video, feed, swing thought) is part of the context that produced it, so trials with every aid removed are the measurement, while the pooled evidence shows no effect of feedback frequency as such and a content reversal when feedback points attention externally. The Winstein and Schmidt page would not open in this run, so the guidance finding is carried on the review and the meta-analysis. For the page: the aids are scaffolding and the test is scheduled without them.

Observation: the on-target literature on changing an established technique in automated performers is thin. Carson and Collins 2011 define their object as refinement, a small tweak or polish rather than a completely new movement, and state that testing their model against implicit motor learning and existing coaching approaches is still required; Carson and Collins 2015 is a three-golfer case series; Hanin, Korjus, Jouste and Baxter 2002, the Old Way/New Way contrast method the Gemini leg relies on, is two Olympic-athlete case studies; Milanese et al 2016 (INTERVENTION, 34 golfers, one-week retention) and Gray 2018 (INTERVENTION, experienced batters, six weeks) correct or shift a single identified feature and report no competition transfer. No leg opened a study that assigned experienced adults to a large versus a small technique change with matched dose, delayed uncued retention and representative transfer, and all four legs said so. Inference from the granted mechanisms: the non-erasure law (A2) means a larger change recruits more anterograde interference; the entrenchment law (A4, S10) means cost scales with the automaticity of what is replaced; the explicit-control debt law (A5) means a larger change installs more declarative rules and so more pressure liability. The opposite inference, that a small change is absorbed into the old attractor and a large change escapes it, is argued by the Gemini leg from dynamical-systems reasoning and the two case studies, and is not refuted by any opened measurement. Decision principle, not a measured effect: change the smallest set of control variables whose contact-mechanics consequence is large, test retention and transfer, and widen scope only when the narrower change fails those tests or when the old pattern is mechanically unable to produce the target ball. Boundary: this is a SIGNAL axiom; the scope comparison is unmeasured in any population and the case evidence is n = 3 and n = 2.

The size of a technique change sets how much of the coordination must be re-bound to new cues, how much automatic retrieval must be inhibited per trial and how many declarative rules carry the assembly. Each of those costs is measured to rise with the quantity changed, so on the measured mechanisms expected cost is increasing in scope. The counter-mechanism, that similar patterns compete for one cue set and a dissimilar pattern earns its own context, is a modeling argument about cue separation that would reduce retrieval competition at the price of the other three costs; which dominates has not been measured.

Granted tier: SIGNAL, set by the code gate on October 4, 2026 · Refuted by the adversary on a source said less than the claim · Sources: 6 cited, 5 opened and confirmed

• TRIPWIRE: this axiom's own source(s) S11 (number_not_on_page) were wrong -> SIGNAL (the tripwire hits the axiom whose use of a source was wrong)

S11 (refinement defined as tweak, comparison still required), S12 (three elite golfers, heterogeneous outcomes), S29 (two Olympic case studies of the contrast method), S31 (34 golfers, single-fault correction, one-week retention), S32 (experienced batters, single-feature shift, six weeks), S10 (change cost scales with old-pattern proficiency).

• S11Carson & Collins 2011, Refining and regaining skills in fixation/diversification stage performers: the Five-A Model (International Review of Sport and Exercise Psychology)opened, the number was not on the pagetechnical refinement in already-automated performers is a different problem from acquisition; the model proposes Analysis, Awareness, Adjustment, Re-automation, Assurance; testing against implicit motor learning is still required
• S12Carson & Collins 2015, Tracking Technical Refinement in Elite Performers: The Good, the Better, and the Ugly (International Journal of Golf Science)opened, quote confirmedthree elite golfers changing an established technique: kinematic change and reduced conscious control came apart; one achieved the change without reduced mental effort, one both, one neither; the more overlearned the execution, the harder the change
• S29Hanin, Korjus, Jouste & Baxter 2002, Rapid Technique Correction Using Old Way/New Way: Two Case Studies with Olympic Athletes (The Sport Psychologist)opened, quote confirmedtwo Olympic-athlete case studies of deliberate old-pattern versus new-pattern contrast practice; the evidence class for the wedge method is case report
• S31Milanese et al 2016, Correction of a Technical Error in the Golf Swing: Error Amplification Versus Direct Instruction (Journal of Motor Behavior)opened, quote confirmed34 golfers randomized to error amplification, direct instruction or control; a single technical fault corrected with motion capture and a one-week retention test; full-text effect sizes unverified by any leg
• S32Gray 2018, Comparing cueing and constraints interventions for increasing launch angle in baseball batting (Sport, Exercise, and Performance Psychology)opened, quote confirmedexperienced batters, six weeks: an individually adjusted barrier constraint beat internal and external cueing on bat-path and ball outcomes; delayed retention and competition transfer not verified from the abstract
• S10Sperl, Gergeleit & Cañal-Bruland 2021, On the role of different subdimensions of inhibition for successful motor skill change (Human Movement Science)opened, quote confirmed42 adults, a swapped keyboard mapping: better performance on the old mapping predicted larger disruption on the new one; response-inhibition measures predicted the disruption

The page may say the strokes are being rebuilt against their mechanics; it may not say that a complete rebuild beats targeted change, because that comparison has never been run; the lawful wording is that each stroke is changed as much as its contact mechanics require and tested before the change is widened.

The scope-of-change law is the axiom that bounds the page's second sentence, Not tweaks, a complete rebuild: no controlled study has compared a wholesale change with a constrained change in experienced adults with delayed retention and representative transfer, the measured mechanisms (interference, entrenchment, explicit-rule load) price a larger change higher, the wholesale case rests on two Olympic case reports and dynamical-systems argument, and the one documented warrant for wholesale change is that the old pattern mechanically cannot produce the target ball, which is a the stroke contact flight and bounce vector question. It sits at the bottom rung by its own claim and by the metadata-only golf page. The page may say each stroke is changed as far as its contact mechanics require and tested before the change is widened; it may not say that a complete rebuild beats targeted change.

For any reply a tennis receiver might choose, the commitment time plus the remaining motor work must not exceed the interception time of that reply; the interception time and the motor work both depend on which reply is chosen, so there is no single ball deadline, and taking the ball early, blocking, retreating and a full swing each carry a different deadline. The chain that fills the interval (pickup, prediction, choice, initiation, movement) is bookkeeping, not five serial stages: prediction runs while the opponent prepares, general preparation precedes directional commitment, and ball flight can still revise an unfolding response. In measured play the first racket movement of 10 skilled receivers came 129 ms after contact against a live hitter and 179 ms against a cloaked ball machine at matched flight times (S3, within-person, skilled college-level players), and a ground-stroke receiver denied the first third of ball flight started the forward swing earlier and lengthened it rather than failing (S31, within-person, 113 km/h feeds). Scope: an analytical constraint plus two within-person measurements on skilled players; the exact milliseconds are those studies', not constants.

Interception requires the racket at a point in space at the moment the ball reaches it; the ball's flight is fixed by the opponent's contact, drag, bounce and distance, while the receiver's remaining displacement, body organisation and racket path depend on where and how the receiver chooses to meet it. Finite acceleration makes remaining motor work a time cost, so earlier commitment, better starting position and a simpler reply are interchangeable ways to satisfy one inequality; a visible first step measures the sum of several overlapping processes, not a completed internal decision.

Granted tier: SIGNAL, set by the code gate on October 4, 2026 (the writer claimed FORGED) · Refuted by the adversary on a source said less than the claim · Sources: 5 cited, 3 opened and confirmed

• TRIPWIRE: this axiom's own source(s) S31 (misquote) were wrong -> SIGNAL (the tripwire hits the axiom whose use of a source was wrong)
• CLAMPED: claimed FORGED -> granted SIGNAL (gate lowers, never raises)

S3 and S4 (Shim et al. 2005, Experiment 2: 129 vs 179 ms initiation, live vs machine, matched flight time; fetched by the openai-dr and exa legs 2026-10-04, published 2005). S31 (return-of-serve kinematics: swing initiation earlier and duration longer with the first third of flight occluded; movement scaled to delivery time; anthropic leg extract). S1 and S2 (Triolet et al. 2013: the 140 to 160 ms transition that operationalises when post-contact information can first have caused a movement). The inequality itself is an analytical MODEL statement from the openai-dr and exa legs, not a fitted tennis equation.

• S1Triolet, Benguigui, Le Runigo & Williams 2013, Quantifying the nature of anticipation in professional tennis, J Sports Sci 31(8)opened, quote confirmedProfessional-match video coding: reaction-to-anticipation transition 140 to 160 ms after contact; anticipation in 6.14 to 13.42 percent of coded situations, almost only when tactically disadvantaged; accuracy non-monotonic, rising again for responses earlier than about 120 ms before contact
• S2HAL open-archive record of Triolet et al. 2013opened, quote confirmedSame record as S1, the open-archive copy the exa leg opened
• S3Shim, Carlton, Chow & Chae 2005, J Motor Behavior 37(2)did not open13 skilled vs 12 novice players: four-alternative anticipation 63.1 vs 43.7 percent (chance 25); skilled players not more accurate than novices with point-light displays; 10 experts initiated racket movement 129 ms after contact against a live hitter vs 179 ms against a cloaked ball machine
• S4Shim et al. 2005 abstract record (exa library)opened, quote confirmedAbstract of S3: skilled more accurate with live and video but not point-light displays; faster reaction latencies against a live opponent
• S31The kinematics of the return of serve in tennis: the role of anticipatory information (The Sport Journal)misquoteMean ball speed 113 km/h, delivery time 1.1 s: median initial movement 0.38 s against a ball machine vs 0.41 s against a real server; occluding the first third of ball flight brought the forward swing earlier and lengthened it; no server-kinematic timing use up to 125 km/h

For the page: 'decision speed' is not a thing a stopwatch on the first step measures; any sentence that treats an earlier first movement as faster deciding must be rewritten as 'earlier usable information, a lower commitment threshold, a better starting position or a simpler reply', each a separate lever. For the player: slack against the deadline can be bought on the motor side (position, a shorter reply) as readily as on the perceptual side.

The deadline law reframes decision speed as an inequality rather than a stopwatch reading: commitment time plus remaining motor work must fit the interception time of the chosen reply, so position, a simpler reply and earlier cue use buy the same slack and a first-movement latency sums several processes. The gate pulled it to the bottom rung on a confirmed misquote: the return-of-serve record tested speeds of a hundred and a hundred and twenty-five kilometres an hour, not the speed quoted, and reported no consistent movement difference between ball machine and live server, so the sentence built on it must be corrected before the page uses it. The Shim live-versus-machine initiation figures come from a page that would not open and a library abstract that confirms only the direction. The analytical inequality itself needs no source.

In video coding of professional tennis matches, the transition between reaction (100 percent correct placement of the response) and anticipation (less than 100 percent) sat 140 to 160 ms after the opponent's contact, anticipatory responses made up 6.14 to 13.42 percent of coded situations (denominator: coded rally situations in professional matches; design: observational video coding; population: touring professionals), and they appeared almost exclusively when the responder was tactically disadvantaged (S1, S2, published 2013). Accuracy did not fall monotonically as responses came earlier: it rose again for responses initiated more than about 120 ms before contact, which the authors attribute to situations carrying unusually strong contextual information (S1). Scope: an observational benchmark from professional matches on more than one surface; the percentages are proportions of coded situations, not of points, and the 140 to 160 ms boundary is an operational definition of this coding, not a physiological constant.

Waiting for post-contact ball flight yields near-certain direction information, so a receiver with time to spare chooses that regime; when the opponent's shot removes that time (a tactically unfavourable situation), the receiver is pushed into committing on pre-contact information, which is probabilistic and therefore sub-100 percent accurate. Very early commitments occur only where the situation itself has nearly one viable opponent reply, so the prior is strong and accuracy recovers; the mid-window, where kinematic evidence tempts commitment but is still ambiguous, is where errors concentrate.

Granted tier: PROBABLE, set by the code gate on October 4, 2026 (the writer claimed FORGED) · Survived the adversary's attack · Sources: 2 cited, 2 opened and confirmed

• PROBATION: 1 misquote flag elsewhere in this vector (below the kill line of 2); this axiom's own sources were clean -> capped at PROBABLE
• survived a grounded cross-lab adversary (google vs authors ["anthropic"])
• citations: refetched 84% (>=90%), resolved 96% (>=80%) -> BELOW FLOOR
• dead links: 5 of 31 source(s) would not open, a miss counted in the ratio above, never a misquote
• EARNED PROBABLE: one of {grounded cross-lab adversary, verified sources} but not both
• CLAMPED: claimed FORGED -> granted PROBABLE (gate lowers, never raises)

S1 (PubMed abstract of Triolet, Benguigui, Le Runigo & Williams 2013, opened by the openai-dr and anthropic legs 2026-10-04; publication 2013) and S2 (HAL open-archive record opened by the exa leg). All three figures (140 to 160 ms, 6.14 to 13.42 percent, the non-monotonic rise before 120 ms) are reported in that abstract; the reading that the early-response accuracy reflects context is the authors' inference, marked as inference. The exa and openai-dr legs both state these are ecological estimates for coded situations rather than constants.

• S1Triolet, Benguigui, Le Runigo & Williams 2013, Quantifying the nature of anticipation in professional tennis, J Sports Sci 31(8)opened, quote confirmedProfessional-match video coding: reaction-to-anticipation transition 140 to 160 ms after contact; anticipation in 6.14 to 13.42 percent of coded situations, almost only when tactically disadvantaged; accuracy non-monotonic, rising again for responses earlier than about 120 ms before contact
• S2HAL open-archive record of Triolet et al. 2013opened, quote confirmedSame record as S1, the open-archive copy the exa leg opened

For the page: a sentence implying that great players 'decide faster' on most balls misdescribes about 87 to 94 percent of coded professional situations, where the response waited for ball flight; the defensible wording is that the better player is pushed into guessing less often and guesses on stronger context when pushed. For the skill under pressure vector: evidence that pressure matters cannot be read as evidence that decision speed is the routine separator.

The reaction law is the single most important bound on the page's decision-speed headline, and it was confirmed verbatim on both the Europe PMC and HAL records: in coded professional matches the responder waited for ball flight in the large majority of situations, anticipated in a small minority, almost only when tactically disadvantaged, and very early reads leaned on strong context. The page may say the better player is pushed into guessing less often and guesses on stronger context when pushed; it may not say great players decide faster on most balls. For the skill under pressure vector it means evidence that pressure matters cannot be read as evidence that speed is the routine separator.

A receiver's prediction of the opponent's shot combines contextual priors (court positions, rally state, known tendencies) with kinematic likelihoods from the opponent's unfolding body and racket motion, weighted by the reliability of each channel at that instant: priors dominate early in the stroke and whenever kinematics are ambiguous, kinematics dominate in the final window before contact (S27, review of within-person manipulation studies). Measured signatures: telling players a disguise was unlikely or likely shifted classification of ambiguous movements across 25, 50 and 75 percent conditions (S27); with stroke kinematics held constant, skilled players' judgements followed the opponent's court position more than less-skilled players' did, and both groups were above chance with postural information removed (S28, cross-sectional); adding movement cues to a context-only animation raised experts from 50.0 to 68.45 percent while novices stayed near 38 percent (S8, cross-sectional, experts and novices); in stochastic masking of ground strokes, information that supported correct direction judgements accrued mainly in the last 0.083 s before contact in 34 skilled non-elite players (ITN 1.6 to 2.8), with only a suggestive torso signal (S17). Scope: laboratory video and animation tasks in skilled and novice adults; the weighting is a model that fits these manipulations, and no study here measured it on court.

Two information sources about one future event are combined most accurately when each is weighted by its inverse variance; early in a stroke the body has not yet differentiated between shots, so the kinematic likelihood is flat and the prior carries the estimate, while in the final 80 to 100 ms the arm and racket commit and the likelihood sharpens. Skill is calibration of the weights, not possession of one channel: novices can use salient context but cannot extract the late kinematic signal (S8, S30), and experts lean less on tendencies as kinematics become reliable.

Granted tier: SIGNAL, set by the code gate on October 4, 2026 (the writer claimed FORGED) · Refuted by the adversary on a claim no opened source could verify · Sources: 5 cited, 3 opened and confirmed

• PROBATION: 1 misquote flag elsewhere in this vector (below the kill line of 2); this axiom's own sources were clean -> capped at PROBABLE
• ATTACK VOID: the refutation rests on a source that would not open (reason_class unverifiable), a miss, never a refutation; neither a kill nor a pass, the grade follows the sources test alone
• citations: refetched 84% (>=90%), resolved 96% (>=80%) -> BELOW FLOOR
• dead links: 5 of 31 source(s) would not open, a miss counted in the ratio above, never a misquote
• EARNED SIGNAL: neither a grounded cross-lab adversary survived nor sources confirmed
• CLAMPED: claimed FORGED -> granted SIGNAL (gate lowers, never raises)

S27 (Gredin et al. 2020 review; the 25/50/75 percent disguise-expectation shift; anthropic leg extract, publication 2020). S28 (court-position manipulation with kinematics constant; anthropic leg). S8 (Murphy, Jackson & Williams 2019, opened by the openai-dr leg: 50.0 to 68.45 percent experts, about 38 percent novices, 1.74 vs 1.96 options generated). S17 (Mann et al. 2019 stochastic masking, opened 2026-10-04: accrual window about 0.083 s, mean 63.2 percent correct, 34 skilled non-elite players). S30 (2022 pilot: only experts improved with late kinematics; both groups used dynamic context; exa leg). Observation: the accuracy shifts under each manipulation. Inference: the reliability-weighted combination that explains them.

• S8Murphy, Jackson & Williams 2019, informational constraints, option generation and anticipationopened, quote confirmedExperts rose from 50.0 to 68.45 percent when movement cues were added to context-only animation; novices stayed about 38 percent; participants generated 1.74 options per trial with video vs 1.96 with animation
• S17Mann, Buscombe et al. 2019, Front Psychol (published 2019-08-27), information accrual before racket-ball contact by stochastic maskingopened, quote confirmed34 skilled non-elite players (ITN 1.6 to 2.8): information for ground-stroke direction accrued mainly in a window reaching back about 0.083 s before contact; spatial result only suggestive of the torso; mean 63.2 percent correct
• S27Gredin, Bishop, Williams & Broadbent 2020 review, Int Rev Sport Exerc Psychol, the use of contextual priors and kinematic information in anticipationdid not openReliability-weighted integration of priors and kinematics: priors weigh more early and when kinematics are ambiguous, kinematics late; stated disguise probability shifted classification of ambiguous movements (25 vs 50 vs 75 percent)
• S28Contextual cue utilization in visual anticipation in tennis: the opponent's on-court positiondid not openWith stroke kinematics held constant, skilled players' judgements were more influenced by the opponent's court position than less-skilled players'; both groups above chance with postural information removed
• S30Pilot study on dynamic-contextual and kinematic information in tennis anticipation, Movement & Sport Sciences 2022opened, quote confirmedExperts and novices both used dynamic context (court positions); only experts anticipated from low context and only experts improved when late kinematic information was added

For the page: 'reading the opponent' splits into two trainable channels with different timing; a rebuilt game that studies an opponent's tendencies improves the early channel, and a game that learns the late arm-racket signal improves the final 100 ms, and neither is a reflex. For the taking time and comfort vector: an opponent who raises kinematic ambiguity (disguise) forces the receiver onto the prior channel, which the skill under pressure vector's pressure evidence shows is the channel anxiety taxes.

The two-channel law (context priors early, arm-racket kinematics in the last tenth of a second, weighted by reliability) is the mechanism behind every anticipation finding in the run, and the stochastic-masking study that locates the late accrual window was opened. The gate held it at the bottom rung because the Gredin review and the court-position manipulation would not open, so the disguise-expectation shift and the skilled-player position weighting are unverified here. The page may say reading the opponent splits into two trainable channels with different timing; the folk instruction to watch the hips is bounded to a suggestive torso signal.

The anticipation advantage of skilled players over less-skilled players is located in the shot-specific information carried by the opponent's movement, not in looking behaviour: skilled players responded about 137 ms earlier with different gaze organisation but no difference in fixation number or mean duration (S5, cross-sectional); replacing arm-racket dynamics with those of the opposite shot cost skilled players accuracy and was the largest decrement, while less-skilled players were hurt only by that swap (S6); removing the ball toss dropped skilled players to chance in a serve stimulus set (S7); and skilled players were not more accurate than novices on point-light displays in one coupled task (S3), so an advantage that survives texture removal in some studies did not in this one. Because the content is emitted by the sender, the sender can cut it: disguise removed the expert advantage at 40 ms before contact and pushed novices below chance on disguised shots occluded at contact (S25, cross-sectional, experts vs novices), and anxiety increased directional errors most in the context-only condition (S26). Scope: laboratory video manipulations in skilled and novice adults; gaze measures are allocation data and cannot by themselves show extraction.

Information about shot direction exists only where the opponent's movement differs between shots; eye position sets what is sampled, but peripheral and parafoveal vision carry biological motion, so fixation location is neither necessary nor sufficient for extraction. A manipulation that changes the content while leaving the display region visible (swapping dynamics) isolates content from looking; removing a region confounds content with attention. A deceiving opponent emits false content, so a model that credits the content is driven below chance, which is the fingerprint distinguishing deception from mere noise.

Granted tier: SIGNAL, set by the code gate on October 4, 2026 (the writer claimed PROBABLE) · Refuted by the adversary on a claim no opened source could verify · Sources: 7 cited, 4 opened and confirmed

• PROBATION: 1 misquote flag elsewhere in this vector (below the kill line of 2); this axiom's own sources were clean -> capped at PROBABLE
• ATTACK VOID: the refutation rests on a source that would not open (reason_class unverifiable), a miss, never a refutation; neither a kill nor a pass, the grade follows the sources test alone
• citations: refetched 84% (>=90%), resolved 96% (>=80%) -> BELOW FLOOR
• dead links: 5 of 31 source(s) would not open, a miss counted in the ratio above, never a misquote
• EARNED SIGNAL: neither a grounded cross-lab adversary survived nor sources confirmed
• CLAMPED: claimed PROBABLE -> granted SIGNAL (gate lowers, never raises)

S5 (Williams et al. 2002: 137 ms earlier, no fixation-count difference; openai-dr leg opened the full text). S6 (Williams et al. 2009 dynamics swap; PubMed 19081648 opened by openai-dr). S7 (Jackson & Mogan 2007; openai-dr). S3 and S4 (Shim et al. 2005 Experiment 1: no skilled advantage with point-light; exa abstract and openai-dr full text). S25 (Jackson, Warren & Abernethy 2006 disguise; anthropic leg extract from a secondary record, not opened at source). S26 (Cocks et al. 2016; anthropic leg extract). The 2006 and 2016 rows are abstract-level, which is why the tier claim stops at PROBABLE.

• S3Shim, Carlton, Chow & Chae 2005, J Motor Behavior 37(2)did not open13 skilled vs 12 novice players: four-alternative anticipation 63.1 vs 43.7 percent (chance 25); skilled players not more accurate than novices with point-light displays; 10 experts initiated racket movement 129 ms after contact against a live hitter vs 179 ms against a cloaked ball machine
• S4Shim et al. 2005 abstract record (exa library)opened, quote confirmedAbstract of S3: skilled more accurate with live and video but not point-light displays; faster reaction latencies against a live opponent
• S5Williams, Ward, Knowles & Smeeton 2002, J Exp Psychol Applied 8(4)did not openSkilled players responded about 137 ms earlier; fixation number and mean duration did not differ; 45 min video plus 45 min on-court training in recreational adults moved field onset 2195.8 to 2001.0 ms, about 186 ms earlier than pooled placebo and control, d = 1.03, no accuracy difference
• S6Williams, Huys, Canal-Bruland & Hagemann 2009, swapping movement dynamics in tennis anticipationopened, quote confirmedSkilled players lost accuracy when proximal or arm-racket dynamics were replaced by the opposite shot's dynamics; less-skilled players lost accuracy only for the arm-racket swap
• S7Jackson & Mogan 2007, spatial occlusion of tennis servesopened, quote confirmedRemoving the ball toss or arm-racket region impaired skilled players' direction judgements; with the toss removed skilled performance fell to chance in this stimulus set
• S25Jackson, Warren & Abernethy 2006, the effect of disguise on anticipationdid not openExperts more accurate overall (p < .001); disguise reduced accuracy (p = .001) and removed the expert advantage at 40 ms before contact; novices below chance on disguised shots occluded at contact
• S26Cocks, Jackson, Bishop & Williams 2016, Cognition and Emotion, anxiety, anticipation and contextual informationopened, quote confirmedSkilled players higher in accuracy and processing efficiency; high anxiety lowered processing efficiency with no accuracy change; directional errors under anxiety largest in the context-only condition

For the page: a rebuilt game cannot promise to 'read' information an opponent does not emit, and a visual drill that copies an expert's fixations trains looking, not interpretation; the sentence to keep is that interpretation of movement content is learned. For the taking time and comfort vector: disguise is a measured lever an opponent holds over the receiver's accuracy, with the below-chance novice result as its signature.

The cue-content law separates what an expert sees from where an expert looks: the advantage lives in shot-specific movement content the sender emits, gaze is allocation, and disguise is the sender's cut in that content, which erases the expert advantage and drives novices below chance. Three of its seven sources would not open (the Williams full text, the dynamics-swap study and the disguise study), which is why the gate held it at the bottom rung and why the taking time and comfort vector, when it runs, must re-open the disguise record before using it as an opponent-side lever. For the page: a drill that copies an expert's fixations trains looking, not interpretation.

A receiver can respond earlier by committing on less evidence (moving along a speed-accuracy frontier, with more errors at fixed evidence quality) or by obtaining more discriminative evidence sooner (moving the frontier); mean response time therefore does not measure processing speed, and training that lowers caution is not the same as training that improves information use (S12, diffusion-model account). Measured: in a one-session occlusion protocol with 39 male expert players (mean age 28.1), response time fell in every group, 734.82 to 463.59 ms in the same-opponent group, 584.42 to 431.24 ms in the varied-opponent group and 687.34 to 589.36 ms in the control group, with no group-by-test interaction, while only the same-opponent group gained accuracy (about 55 to 65 percent), so the shared latency drop is task familiarisation and the differential effect is prediction quality (S9, S10, randomized, published 2025-01-07). In recreational adults, 90 minutes of training moved field response onset about 186 ms earlier (d = 1.03) with no accuracy change, a package effect that does not isolate encoding or choice (S5, randomized with placebo and control). In match coding, accuracy was non-monotonic in time-to-contact (S1). Scope: laboratory and field-feed designs in expert and recreational adults; the model is general decision theory, the tennis measurements are these studies'.

In an evidence-accumulation process, accuracy and mean decision time both rise with the ratio of threshold to noise: at fixed drift and noise, raising the dimensionless threshold from 0.5 to 1 moves idealized accuracy from about 73 to 88 percent while mean decision time grows about 3.3-fold (an illustrative calculation, not a tennis estimate). Raising drift (better evidence sooner) shortens time and raises accuracy together. An observed latency change is therefore a projection of two parameters onto one axis, and only matched-accuracy latency or matched-occlusion accuracy comparisons separate them.

Granted tier: SIGNAL, set by the code gate on October 4, 2026 (the writer claimed FORGED) · Refuted by the adversary on a claim no opened source could verify · Sources: 5 cited, 4 opened and confirmed

• PROBATION: 1 misquote flag elsewhere in this vector (below the kill line of 2); this axiom's own sources were clean -> capped at PROBABLE
• ATTACK VOID: the refutation rests on a source that would not open (reason_class unverifiable), a miss, never a refutation; neither a kill nor a pass, the grade follows the sources test alone
• citations: refetched 84% (>=90%), resolved 96% (>=80%) -> BELOW FLOOR
• dead links: 5 of 31 source(s) would not open, a miss counted in the ratio above, never a misquote
• EARNED SIGNAL: neither a grounded cross-lab adversary survived nor sources confirmed
• CLAMPED: claimed FORGED -> granted SIGNAL (gate lowers, never raises)

S12 (Ratcliff, Thapar & McKoon 2006, opened by the openai-dr leg: evidence quality and criterion as separate practice-sensitive parameters). S9 and S10 (Triolet & Benguigui 2025, opened 2026-10-04: all group response-time and accuracy figures; no interaction on response time). S5 (Williams et al. 2002 intervention: 2195.8 to 2001.0 ms, d = 1.03, no accuracy difference; clocks started at the feed, not at contact). S1 (Triolet 2013 non-monotonic accuracy). The 73 to 88 percent and 3.3-fold figures are an openai-dr MODEL illustration and are marked as such.

• S1Triolet, Benguigui, Le Runigo & Williams 2013, Quantifying the nature of anticipation in professional tennis, J Sports Sci 31(8)opened, quote confirmedProfessional-match video coding: reaction-to-anticipation transition 140 to 160 ms after contact; anticipation in 6.14 to 13.42 percent of coded situations, almost only when tactically disadvantaged; accuracy non-monotonic, rising again for responses earlier than about 120 ms before contact
• S5Williams, Ward, Knowles & Smeeton 2002, J Exp Psychol Applied 8(4)did not openSkilled players responded about 137 ms earlier; fixation number and mean duration did not differ; 45 min video plus 45 min on-court training in recreational adults moved field onset 2195.8 to 2001.0 ms, about 186 ms earlier than pooled placebo and control, d = 1.03, no accuracy difference
• S9Triolet & Benguigui 2025, Anticipation training for expert tennis players when facing a specific player, Front Psychol 15:1508627 (published 2025-01-07)opened, quote confirmed39 male expert players (mean age 28.1), three groups of 13, clips occluded 340 ms before contact, 72 training trials in one ~1 h session; only the same-opponent group raised accuracy (about 55 to 65 percent); response time fell in every group (734.82 to 463.59, 584.42 to 431.24, control 687.34 to 589.36 ms) with no group-by-test interaction; retention and court transfer not tested
• S10PMC copy of Triolet & Benguigui 2025opened, quote confirmedSame record as S9, opened 2026-10-04 and read for the group-level numbers
• S12Ratcliff, Thapar & McKoon 2006, aging and practice in masked perceptual tasks (diffusion model)opened, quote confirmedCollege-age and 60 to 75 year old adults: practice improved evidence quality and changed decision criteria; older adults approached younger accuracy after four sessions; nondecision time stayed somewhat slower

For the page: 'deciding faster under pressure' is not a well-formed training goal, because a lower criterion buys speed with errors; the sentence that survives is 'commit on better evidence earlier', and any claimed gain must be shown at matched accuracy. For the skill under pressure vector: a pressure manipulation that lengthens response time while accuracy holds is a criterion or efficiency effect, not a loss of skill, and the two must be reported separately.

The frontier law says that a faster response identifies no component: speed can be bought by committing on less evidence or earned by getting better evidence sooner, and only the second raises accuracy. Its decisive tennis fact was confirmed on the 2025 Triolet and Benguigui record, where every group including the control got faster while only the same-opponent group gained accuracy, so a latency drop was task familiarisation. The Williams 2002 training page would not open. For the page the sentence that survives is commit on better evidence earlier, with any claimed gain shown at matched accuracy, which is why deciding faster under pressure is not a well-formed training goal.

In adults, the prediction components of anticipation move under controlled training: 72 feedback trials on one opponent's serves, occluded 340 ms before contact, raised accuracy only in the same-opponent group of expert players (about 55 to 65 percent; varied-opponent and control groups unchanged), in a single session, with retention and court transfer untested (S9, S10, randomized, 39 experts, published 2025-01-07); 38 adults without substantial tennis experience (mean age 19.5) rose from 59.1 to 74.3 percent when trained with the arm-racket region visible and transferred the gain to untrained regions, while the group trained with that region hidden stayed at 62.5 to 62.3 percent (S11, randomized to display condition, laboratory stick figures, 2013); 21 intermediate players (about 20.8 years) trained on rally-ordered clips reached a field decision time of 275 ms (SD 31) against 305 ms (SD 46) for quasi-random clips after three 24-trial sessions, with accuracy at ceiling above 90 percent in both (S16, 2017); random practice beat blocked practice on 7-day laboratory retention and on field decision time (S14, S15, 2015); a 3-week occlusion programme improved high-performance players more than beginners among 32 participants (S29, abstract-level, 2025). Scope: adult experts, intermediates and novices in laboratory and field-feed tasks; none of these measured match outcomes.

Learning a shot-specific mapping requires that the training display preserve discoverable, reliable information (the arm-racket region) and that feedback link the display to the outcome; a display stripped of the informative region yields no learning (S11). Opponent-specific exposure sharpens the prior for that opponent (S9) without changing generic speed. A rally-ordered sequence restores the contextual prior that isolated clips remove, so the learned skill includes the early channel and transfers to a field decision measured before the ball is struck (S16); random ordering forces reconstruction of the discrimination on each trial, which costs acquisition and buys retention (S14).

Granted tier: PROBABLE, set by the code gate on October 4, 2026 (the writer claimed FORGED) · Survived the adversary's attack · Sources: 7 cited, 7 opened and confirmed

• PROBATION: 1 misquote flag elsewhere in this vector (below the kill line of 2); this axiom's own sources were clean -> capped at PROBABLE
• survived a grounded cross-lab adversary (google vs authors ["anthropic"])
• citations: refetched 84% (>=90%), resolved 96% (>=80%) -> BELOW FLOOR
• dead links: 5 of 31 source(s) would not open, a miss counted in the ratio above, never a misquote
• EARNED PROBABLE: one of {grounded cross-lab adversary, verified sources} but not both
• CLAMPED: claimed FORGED -> granted PROBABLE (gate lowers, never raises)

S9 and S10 (Triolet & Benguigui 2025; opened 2026-10-04, numbers as reported). S11 (Smeeton, Huys & Jacobs 2013 Experiment 3; opened 2026-10-04). S16 (Broadbent et al. 2017; opened 2026-10-04: 275 vs 305 ms, p = .05, retention 79 vs 64 percent in the sequential condition). S14 and S15 (Broadbent et al. 2015; Brunel handle opened by openai-dr, Brighton full text by exa). S29 (Carboch et al. 2025 abstract via the exa leg; results table not opened, so it bounds rather than carries). All INTERVENTION class.

• S9Triolet & Benguigui 2025, Anticipation training for expert tennis players when facing a specific player, Front Psychol 15:1508627 (published 2025-01-07)opened, quote confirmed39 male expert players (mean age 28.1), three groups of 13, clips occluded 340 ms before contact, 72 training trials in one ~1 h session; only the same-opponent group raised accuracy (about 55 to 65 percent); response time fell in every group (734.82 to 463.59, 584.42 to 431.24, control 687.34 to 589.36 ms) with no group-by-test interaction; retention and court transfer not tested
• S10PMC copy of Triolet & Benguigui 2025opened, quote confirmedSame record as S9, opened 2026-10-04 and read for the group-level numbers
• S11Smeeton, Huys & Jacobs 2013, PLoS ONE (published 2013-11-11), learning informative movement from stick figuresopened, quote confirmedExperiment 3: 38 adults (mean age 19.5) without substantial tennis experience; the group trained with the arm-racket region visible rose 59.1 to 74.3 percent and transferred to untrained regions; the group trained with it hidden stayed 62.5 to 62.3 percent; on-court transfer not tested
• S14Broadbent, Causer, Ford & Williams 2015, contextual interference in perceptual-cognitive skills training (Brunel repository)opened, quote confirmedRandom vs blocked video practice of tennis anticipation: random group higher accuracy on a 7-day retention test and lower decision times in a field-based transfer protocol
• S15Broadbent et al. 2015 full text (Brighton repository)opened, quote confirmedSame record as S14, the full-text copy the exa leg opened
• S16Broadbent, Ford, O'Hara, Williams & Causer 2017, PLoS ONE (published 2017-03-29), sequential structure of practiceopened, quote confirmed21 intermediate players (mean age about 20.8), 3 sessions of 24 trials: the sequential group's field decision time 275 ms (SD 31) vs 305 ms (SD 46) for the non-sequential group, p = .05; accuracy above 90 percent in both (ceiling); laboratory retention 79 vs 64 percent in the sequential condition
• S29Carboch, Mrazova & Brenton 2025, Int J Sports Sci Coaching, perceptual-cognitive training on serve-return anticipationopened, quote confirmed32 participants split by level into intervention and control; 3-week video occlusion training; high-performance players gained more anticipation performance than beginners; abstract-level, results table not opened

For the page: the trainable part of 'reading the game' in an adult is the prior for a specific opponent, the late arm-racket signal and the use of rally context, and each has a dated adult intervention behind it; the claim that an adult can rebuild perception is UPHELD for these components and silent on match results. For the player's programme: study the opponent you will face, train with the informative region visible, and in rally order.

The adult-learning law is the strongest upheld element for the page's claim to be rebuilding perception: opponent-specific priors moved in one session in experts, the arm-racket-to-direction mapping moved in a laboratory week in novices only when the informative region was visible, rally-ordered practice moved a field decision time in intermediates, and random practice beat blocked on a week's retention. Every source opened; none measured a match outcome. Grouped with the rebuilding a stroke vector's schedule law because the two vectors derived the same practice-structure result from different evidence.

Video-based temporal occlusion training improves anticipation with a large pooled effect, d = 1.21 [0.83, 1.59] across 12 intervention studies, 25 effect sizes and N = 248 from novices to national or international level, and the field-transfer effect, d = 0.85 [0.40, 1.30], did not differ significantly from the video-transfer effect, d = 1.26 [0.80, 1.72], p = 0.211, with publication bias inconclusive on so few studies (S19, meta-analysis, published 2024-08-05, multiple sports). In team sports the discount is explicit: task-specific response-accuracy ES 1.51 [0.98, 2.05] (n = 381) against on-court transfer ES 0.65 [0.15, 1.16] (n = 247); transfer measured by verbal response ES 0.41 [0.07, 0.75] against sport-specific action ES 0.87 [-0.22, 1.96]; adults ES 0.63 [0.29, 0.98] (S20, S21, 22 studies, published 2024-10-09, not tennis). The canonical tennis implicit-training result dissolved on re-analysis: groups differed before training and the placebo group that only watched matches improved most across the four occlusion points up to impact (S22, S23). Scope: pooled sport populations; the tennis-specific transfer estimate is one component of S19, and the team-sport discount is carried as a bound on, not a measurement of, tennis.

A video task with a verbal or button response trains and tests a perceptual judgement uncoupled from the movement it must drive; on court the judgement must be expressed through a timed interception under a shorter effective deadline, so part of the laboratory gain is specific to the uncoupled response and does not survive the coupling. Passive observation of matches also carries information, which is why a placebo that watches tennis can improve and why an active control is required to attribute a gain to the training content.

Granted tier: PROBABLE, set by the code gate on October 4, 2026 · Survived the adversary's attack · Sources: 5 cited, 5 opened and confirmed

• PROBATION: 1 misquote flag elsewhere in this vector (below the kill line of 2); this axiom's own sources were clean -> capped at PROBABLE
• survived a grounded cross-lab adversary (google vs authors ["anthropic"])
• citations: refetched 84% (>=90%), resolved 96% (>=80%) -> BELOW FLOOR
• dead links: 5 of 31 source(s) would not open, a miss counted in the ratio above, never a misquote
• EARNED PROBABLE: one of {grounded cross-lab adversary, verified sources} but not both

S19 (Muller et al. 2024, opened 2026-10-04: all d values and CIs, N = 248, bias inconclusive). S20 and S21 (Zhu et al. 2024, opened 2026-10-04: ES 1.51 vs 0.65, 0.41 vs 0.87, adults 0.63). S22 and S23 (Jackson 2003 re-analysis of Farrow & Abernethy 2002; anthropic leg extract, abstract-level). The exa leg opened the S19 abstract independently; the anthropic leg could not open the S19 numeric table, which this run's fetch supplied.

• S19Muller, Morris-Binelli, Hambrick & Macnamara 2024, Sports Medicine (published 2024-08-05), temporal occlusion training meta-analysisopened, quote confirmed12 intervention studies, 25 effect sizes, N = 248 from novices to national or international level: d = 1.21 [0.83, 1.59]; video transfer d = 1.26 [0.80, 1.72] vs field transfer d = 0.85 [0.40, 1.30], difference p = 0.211; publication bias inconclusive
• S20Zhu et al. 2024, Behavioral Sciences 14:919 (published 2024-10-09), perceptual-cognitive training in team sports meta-analysisopened, quote confirmed22 studies, 45 effect sizes: task-specific response accuracy ES 1.51 [0.98, 2.05] (n = 381) vs on-court transfer ES 0.65 [0.15, 1.16] (n = 247); verbal-response transfer ES 0.41 [0.07, 0.75] vs sport-specific action ES 0.87 [-0.22, 1.96]; adults ES 0.63 [0.29, 0.98]; soccer, rugby and other team sports, not tennis
• S21PubMed record of Zhu et al. 2024opened, quote confirmedSame record as S20
• S22Jackson 2003, re-analysis of Farrow & Abernethy 2002 (J Sports Sci)opened, quote confirmedPre-intervention group differences; the explicit group did improve; the placebo (match-watching) group showed the largest mean improvement across the four occlusion points up to impact
• S23PubMed record of the Farrow & Abernethy 2002 re-analysisopened, quote confirmedSame record as S22

For the page: an interest page may say occlusion training transfers to the court, with the dated pooled estimate and the discount, and may not say that a reaction app or a video score is a court gain; any claim of improvement needs a coupled, on-court measure against an active control. For the player: pair video study with a movement response.

The transfer-discount law prices video and app training: a large pooled video gain, a smaller on-court gain, uncoupled button responses inflating the laboratory number, and a placebo group that watched matches improving most in the canonical tennis study. It is grouped with the rebuilding a stroke vector's three-test and support-removal laws because all three say that a gain measured with the scaffold present is an upper bound. The sharpest discount estimate is from team sports and transfers to tennis only as a bound.

Two adult quantities behave differently under training. The irreducible looking-to-doing latency of a practised real-time task slowed from age 24 [95 percent CI 20, 29] in 3,305 StarCraft 2 players aged 16 to 44, a 39-year-old typical player being about 150 ms slower per cycle than a 24-year-old, with no evidence that expertise attenuated the decline (S24, cross-sectional, correlational, published 2014-04-09, a video game and not tennis). Meanwhile the decision parameters moved with practice in 60 to 75 year olds: evidence quality improved and criteria changed over four sessions of masked perceptual tasks until accuracy approached that of college-age adults, while nondecision time stayed somewhat slower (S12, within-person practice, non-tennis). In tennis, experts intercepting a simulated ball deviated 400 ms before contact were more accurate because their visuo-motor delay in adapting the movement was shorter, and that delay predicted accuracy and national ranking (S18, cross-sectional, 2010), which locates an expertise marker in coupling rather than in a reflex. Eight weeks of plyometrics in 30 male collegiate players improved hexagon-test time 6.2 and 9.2 percent and jump power, with no measure of cue use (S13, randomized, published 2026-06-17). Scope: the floor estimate is from a non-tennis population and transfers to tennis only as a bound; the plasticity estimates are laboratory; no adult intervention on movement time or coupling in tennis was opened.

Sensory noise and conduction set a nondecision time that practice does not shorten and age lengthens, so gains in an adult come from enlarging the window the floor sits in: better priors and cue extraction move the onset of usable evidence earlier, a calibrated criterion removes conservatism, and shorter information-movement coupling lets late ball-flight information still steer the stroke. Physical training changes the motor side of the deadline inequality (movement time) independently of any perceptual change.

Granted tier: PROBABLE, set by the code gate on October 4, 2026 · Survived the adversary's attack · Sources: 4 cited, 4 opened and confirmed

• PROBATION: 1 misquote flag elsewhere in this vector (below the kill line of 2); this axiom's own sources were clean -> capped at PROBABLE
• survived a grounded cross-lab adversary (google vs authors ["anthropic"])
• citations: refetched 84% (>=90%), resolved 96% (>=80%) -> BELOW FLOOR
• dead links: 5 of 31 source(s) would not open, a miss counted in the ratio above, never a misquote
• EARNED PROBABLE: one of {grounded cross-lab adversary, verified sources} but not both

S24 (Thompson, Blair & Henrey 2014; opened 2026-10-04). S12 (Ratcliff, Thapar & McKoon 2006; openai-dr opened). S18 (Le Runigo, Benguigui & Bardy 2010 abstract via the exa library; group delay values not in the abstract). S13 (Pang & Li 2026; openai-dr live fetch). Observation: the age slope, the practice gains, the delay-accuracy correlation, the hexagon times. Inference: that adult gains are window enlargement rather than floor reduction, which no tennis intervention here tests directly.

• S12Ratcliff, Thapar & McKoon 2006, aging and practice in masked perceptual tasks (diffusion model)opened, quote confirmedCollege-age and 60 to 75 year old adults: practice improved evidence quality and changed decision criteria; older adults approached younger accuracy after four sessions; nondecision time stayed somewhat slower
• S13Pang & Li 2026, Front Physiol (published 2026-06-17), plyometric training in collegiate tennis playersopened, quote confirmed30 male collegiate players randomized to two plyometric groups or control for eight weeks: hexagon-test time improved 6.2 and 9.2 percent, jump power improved, T-test not different between groups; no measure of cue use or choice
• S18Le Runigo, Benguigui & Bardy 2010, Visuo-motor delay, information-movement coupling, and expertise in ball sportsopened, quote confirmedTennis experts intercepted a simulated ball deviated 400 ms before contact more accurately than non-experts, explained by a shorter visuo-motor delay; delay predicted accuracy, and accuracy predicted national ranking
• S24Thompson, Blair & Henrey 2014, PLoS ONE (published 2014-04-09), over the hill at 24: cognitive-motor decline in StarCraft 2opened, quote confirmed3,305 players aged 16 to 44: looking-doing latency slows from age 24 [20, 29]; a 39-year-old about 150 ms slower than a 24-year-old; no evidence that expertise attenuates the decline; a real-time strategy game, not tennis

For the page: an adult may claim to rebuild prediction, criterion and coupling, and may not claim to have made his nervous system faster; the honest sentence is that the floor is fixed and the window around it is the work. For the skill under pressure vector and the adult body under load vector: the age slope here is a non-tennis bound and no personal latency is implied; a physical gain in movement time is a separate, measured lever.

The fixed-floor law divides what an adult can and cannot change on the perceptual side: nondecision latency is set by conduction and sensory noise and lengthens with age in a non-tennis sample, while evidence quality, criterion and visuo-motor coupling moved under practice. The page may say the floor is fixed and the window around it is the work; it may not say an adult has made his nervous system faster, and the age slope quoted is a video-game bound with no personal latency implied.

A pressured shot is a launch distribution with a mean (where the player aims and how much risk the choice carries) and a spread (how reliably the body produces that intent), and pressure can move either, in either direction. Touring professionals, seven Grand Slams 2006 to 2007, stroke-by-stroke (S6): men's odds of a winner were about 28 log points lower and of an unforced error 33 log points lower in the top importance quartile than the bottom, a move of the aim toward safety with the ball still in play. Thirty novices at a prescribed table-tennis target (S17): stakes shortened the swing, lowered forward-swing and ball speed and shifted the landing (p<.008) with grip force unchanged, a change of execution with the choice fixed by the task. Touring professionals, more than 650,000 Grand Slam points 2016 to 2019 (S16): a 1-to-5 pressure index raised the probability of a double fault or unforced error (p<.001) and a prior-point error raised it again (OR 1.2, 95% CI 1.17 to 1.23). The S6 and S16 patterns are reconciled only by measuring choice and execution separately. Boundary: professionals (S6, S16, correlational), novices (S17, within-person manipulation), laboratory adults (S11); no row measures an adult club player's shot choice under match pressure.

The outgoing ball is fixed by the collision at contact (impulse, racket orientation, timing), so a shot is a distribution over launch conditions mapped through flight to a landing distribution; its mean is the policy and its covariance is the execution. Any scalar outcome (a point won, an error counted) sums over both and cannot recover either; two shots with the same error rate can have opposite aim shifts. Pressure acts through attention on both the planning of the aim and the online control of the swing (S11), so the two can move in opposite directions in the same player.

Granted tier: PROBABLE, set by the code gate on October 4, 2026 (the writer claimed FORGED) · Refuted by the adversary on a source said less than the claim · Sources: 4 cited, 4 opened and confirmed

• adversary REFUTED the claim
• citations: refetched 100% (>=90%), resolved 100% (>=80%) -> OK
• EARNED PROBABLE: one of {grounded cross-lab adversary, verified sources} but not both
• CLAMPED: claimed FORGED -> granted PROBABLE (gate lowers, never raises)

S6 (professionals, both winners and unforced errors fall with importance: a policy change); S17 (novices, prescribed target, swing shortened and speed fell: an execution change); S16 (professionals, counted errors rise with the pressure index: an outcome measure that mixes the two); S11 (pressure type selects which process is hit). Observation: the log-point changes, the kinematic changes and the odds ratio. Inference: that an error count sums over aim and spread.

• S6Paserman 2010, Gender differences in performance in competitive environments? Evidence from professional tennis players (working paper, January 2010)opened, quote confirmedSeven Grand Slams 2006 to 2007, stroke-by-stroke; men's odds of a winner about 28 log points and of an unforced error 33 log points lower in the top importance quartile than the bottom; women 19 to 44 and 14 to 29 log points lower; professionals play a more conservative, less aggressive strategy as importance rises
• S17Sekiya and Tanaka 2018, Movement modifications related to psychological pressure in a table tennis forehand task (Perceptual and Motor Skills; Semantic Scholar record)opened, quote confirmed30 novices after 135 practice trials; under money and score-cancellation pressure backswing and forward swing shortened, forward-swing and ball speed fell (p<.008), contact shifted forward, landing shifted left (p<.007), grip force unchanged; anxiety and heart rate rose p<.025
• S16Harris, Vine, Eysenck and Wilson 2021, Psychological pressure and compounded errors during elite-level tennis (Psychology of Sport and Exercise; Semantic Scholar record)opened, quote confirmedMore than 650,000 points across 12 Grand Slams 2016 to 2019; a 1-to-5 pressure index raised the probability of a double fault or unforced error (ps<.001); a prior-point error OR 1.2 [1.17, 1.23]; multiplicative; winning players as susceptible to pressure and prior errors as losing players
• S11DeCaro, Thomas, Albert and Beilock 2011, Choking under pressure: multiple routes to skill failure (JEP: General; Europe PMC record)opened, quote confirmedOutcome-contingent pressure (distraction) hurt rule-based category learning; monitoring by others hurt information-integration learning; interventions designed by pressure type (Exp 3); monitoring effect replicated in a serial reaction time task (Exp 4)

For the michaelquoc.com tennis page: a sentence about pressure may state that pressure moves the aim toward safety or shrinks the stroke, with S6 and S17 as its rows, and may not say that errors under pressure show a motor failure. For the player's own work: a pressure diagnosis needs the intended target and the landing spread recorded separately (ball tracking against a stated target), never a tally of misses.

The aim-and-dispersion law is the reading frame for every pressure finding: a pressured shot has a mean (the chosen target and its risk) and a spread (how reliably the body produces it), the Grand Slam point data show professionals moving the aim toward safety on important points while counted errors still rise, and the table-tennis novices show the swing shortening at a fixed target. The adversary's objection stands as a bound the page must carry: no opened source separates aim from dispersion in one design, so the decomposition is the writer's inference across two data sets, not a measured split. For the page: an error count or a lost point cannot say whether the choice or the execution moved.

When 12 skilled (BTMR 10.2 to 8.1, 10.5 years of play) and 12 less-skilled male players anticipated opponents' shots under low and high anxiety (S4; manipulation confirmed, confidence 5.40 vs 6.13, p<.001), response accuracy did not change (F(1,22)=0.06, ηp²=.00) while processing efficiency, accuracy divided by rated mental effort, fell (F(1,22)=20.11, p<.001, ηp²=.48); the only accuracy loss was in the condition carrying context alone and only for the skilled group (Anxiety x Skill on directional errors F(1,22)=5.11, p<.05): anxiety taxed the top-down use of context, not speed. In a scenario task (S12; two experiments of 120, 40 per group, ages 17 to 20, Chinese National Level 1 and 2 players and university students) experts chose in 21,082 ± 514 ms against 25,867 ± 1,034 ms for skilled and 33,925 ± 2,548 ms for novices, with skilled players turning extremely conservative under time pressure and experts choosing by the competitive state: a difference in deliberate preference measured in tens of seconds in adolescents, not an on-court reaction time. Touring professionals (S16): pressure raised counted errors and winners were as susceptible as losers. Boundary: skilled club and university players (S4, within-person), adolescents and students (S12, cross-sectional stated preferences), professionals (S16, correlational); no opened study measures on-court decision time under match pressure in adults.

Anxiety shifts attentional control toward the stimulus-driven system and recruits compensatory effort, so the resources spent per unit of performance rise before the performance itself falls (the efficiency-before-effectiveness signature). Context use is a top-down process and is the first to lose quality, while the reading of postural cues, a bottom-up process, is spared. A player therefore pays for an unchanged outcome with effort and worse use of the point's history, which is why outcome-only designs miss the first and largest pressure effect.

Granted tier: PROBABLE, set by the code gate on October 4, 2026 (the writer claimed FORGED) · Refuted by the adversary on a number larger than the sources support · Sources: 3 cited, 3 opened and confirmed

• adversary REFUTED the claim
• citations: refetched 100% (>=90%), resolved 100% (>=80%) -> OK
• EARNED PROBABLE: one of {grounded cross-lab adversary, verified sources} but not both
• CLAMPED: claimed FORGED -> granted PROBABLE (gate lowers, never raises)

S4 (skilled tennis players: efficiency down ηp²=.48, accuracy unchanged, context-only errors up in the skilled); S12 (scenario decision time and policy stability by level, not pressure-induced slowing); S16 (professionals: errors rise with pressure while winners and losers are equally susceptible). Observation: the F tests, the decision times and the odds. Inference: that the first cost of pressure is efficiency and context use.

• S4Cocks, Jackson, Bishop and Williams 2016, Anxiety, anticipation and contextual information: a test of attentional control theory (Cognition and Emotion)opened, quote confirmed12 skilled vs 12 less-skilled male players; under high anxiety response accuracy unchanged F(1,22)=0.06 while processing efficiency fell F(1,22)=20.11, p<.001, ηp²=.48; skilled players' directional errors rose only in the context-only condition (Anxiety x Skill F(1,22)=5.11, p<.05)
• S12Shangguan and Zha 2025, The impact of framing effects, competitive state, and time pressure on risk-taking decisions in tennis players of different skill levels (Frontiers in Psychology, 2025-11-04)opened, quote confirmedTwo experiments of 120 (40 expert, 40 skilled, 40 novice; ages 17 to 20); scenario decision time novice 33,925 ms, skilled 25,867 ms, expert 21,082 ms; under high time pressure skilled players turned extremely conservative, experts chose by competitive state
• S16Harris, Vine, Eysenck and Wilson 2021, Psychological pressure and compounded errors during elite-level tennis (Psychology of Sport and Exercise; Semantic Scholar record)opened, quote confirmedMore than 650,000 points across 12 Grand Slams 2016 to 2019; a 1-to-5 pressure index raised the probability of a double fault or unforced error (ps<.001); a prior-point error OR 1.2 [1.17, 1.23]; multiplicative; winning players as susceptible to pressure and prior errors as losing players

The page's 'decision speed under pressure' is rewritten to what is measured: under anxiety a skilled player's reads stay as accurate but cost more effort and lose the use of the point's context first. For the player's own training: an on-court measure of decision quality (choice against the situation) with the effort it costs, not a reaction-time number, is the instrument that would show whether pressure is touching his decisions at all.

The efficiency-before-effectiveness law is the direct test of the page's phrase decision speed under pressure in skilled tennis players: under confirmed anxiety, anticipation accuracy did not change, effort rose, and the only accuracy loss sat in context use. The adversary's bounds are real and belong on the page: the sample is two dozen players, and the scenario study that measured decision time did so in tens of seconds on stated preferences in adolescents, which is not an on-court reaction. Decision time under match pressure in adult club players is unmeasured in any opened source, so the page may say pressure taxes attention before it slows the choice, and must leave the clock to measurement.

Outcome-contingent pressure (stakes) pulls attention into worry and hurts processes that need working memory; being watched (monitoring) pulls attention onto the steps of an automated skill and hurts proceduralized execution. In S11 each route hurt a different category-learning task, interventions designed by route removed the choke (Exp 3), and the monitoring route replicated in a serial reaction time task (Exp 4). In proceduralized putting (S18) self-consciousness training eliminated the choke and dual-task training did not. In 53 semi-professional tennis players (29.9 ± 9.0 y, 21.5 y of play) hitting second serves under expert evaluation (S3), anxiety lowered accuracy (B=-.24, p=.04) and the entire effect ran through self-reported distraction (indirect effect 95% CI .04 to .30) with skill-focus carrying nothing (-.02 to .05): in an experienced adult's serve under evaluation the distraction route dominated. A match applies stakes and an audience at once, so a serve is exposed on both routes, and which bites depends on the learning stage (a stroke still run on explicit rules sits on the monitoring route). Boundary: adult semi-professionals (S3, between-person with mediation), laboratory adults (S11), novice and expert golfers (S18); no tennis mediation test in juniors or club adults was opened.

Skilled action is controlled by two attentional systems; pressure biases the allocation. Stakes load working memory with outcome worry and starve attention-demanding processes (choice, context use); observation raises self-focus and re-engages step-by-step control of a skill that runs best without it, which raises movement variability. Which route damages a given stroke depends on where that stroke's control is stored: a long-automated serve is exposed to monitoring, a rebuilt stroke still carried on rules is exposed to both, and an evaluated adult serve in S3 lost through distraction.

Granted tier: PROBABLE, set by the code gate on October 4, 2026 (the writer claimed FORGED) · Refuted by the adversary on unverifiable-unsupported · Sources: 3 cited, 3 opened and confirmed

• adversary REFUTED the claim
• citations: refetched 100% (>=90%), resolved 100% (>=80%) -> OK
• EARNED PROBABLE: one of {grounded cross-lab adversary, verified sources} but not both
• CLAMPED: claimed FORGED -> granted PROBABLE (gate lowers, never raises)

S11 (type-by-task crossover, interventions by type, SRT replication); S18 (self-consciousness training removes the putting choke, dual-task training does not); S3 (tennis second serve: anxiety effect fully mediated by distraction, not skill-focus). Observation: the mediation intervals and the crossover. Inference: the routing rule.

• S11DeCaro, Thomas, Albert and Beilock 2011, Choking under pressure: multiple routes to skill failure (JEP: General; Europe PMC record)opened, quote confirmedOutcome-contingent pressure (distraction) hurt rule-based category learning; monitoring by others hurt information-integration learning; interventions designed by pressure type (Exp 3); monitoring effect replicated in a serial reaction time task (Exp 4)
• S18Beilock and Carr 2001, On the fragility of skilled performance: what governs choking under pressure? (JEP: General; Europe PMC record)opened, quote confirmedPutting choked under pressure, alphabet arithmetic did not; in putting, self-consciousness training eliminated the choke while dual-task training did not, supporting explicit-monitoring theories for proceduralized skills
• S3Englert and Oudejans 2014, Is choking under pressure a consequence of skill-focus or increased distractibility? Results from a tennis serve task (Psychology 5:1035-1043)opened, quote confirmed53 semi-professional players (anxiety n=25, neutral n=28), 29.9 y; anxiety lowered second-serve accuracy B=-.24, p=.04; effect fully mediated by self-reported distraction (indirect 95% CI .04 to .30), skill-focus did not mediate (-.02 to .05)

A page sentence about nerves may state the two routes and name S3 as the tennis test that put the loss on distraction; it may not say 'overthinking the stroke is what fails under pressure' as a general law. For the player's own rebuild: a stroke still run on cues is exposed on the monitoring route, so its pressure test is a learning-stage question before it is a nerve question; an attention routine that keeps the mind on the target addresses the route S3 found.

The route law gives the rebuild its pressure prediction: stakes pull attention into worry and hurt working-memory processes, an audience pulls attention onto the steps and hurts proceduralized execution, and in the opened semi-professional serve test the loss ran through distraction with skill-focus carrying nothing. The adversary is right that the word only overreaches; the lawful wording is the one opened tennis mediation test. Grouped with the rebuilding a stroke vector's explicit-control debt law because a rebuilt stroke still run on explicit rules sits on the monitoring route by construction.

In 50 expert golfers across three pressure levels (S10) rising pressure increased anxiety, effort and heart rate and increased putting accuracy while grip force fell, with effort and heart rate partially mediating the gain. In 40 skilled college tennis players (S2) a coach-evaluation and money manipulation raised ball speed (p<.001) and racket speed (p=.013) in both groups and neither group's serve score fell (interaction p=.287); the authors wrote that 'pressure manipulation must be reconsidered' because no choke was induced. In 20 highly skilled juniors (S1) the same class of manipulation lowered the right-hand control group's accuracy (Phase x Group p=.003), so induction worked there. The law: a pressure effect is a within-player contrast whose sign is not fixed, and a protective claim is defined only where the control arm measurably lost accuracy. Boundary: expert golfers (S10, within-person), skilled college players and juniors (S1, S2, randomized two-group); none of these measured shot choice.

Arousal and effort are inputs to motor control as well as costs: raised effort and heart rate can tighten the temporal envelope of a well-learned skill and improve its outcome, and reduced grip force under pressure runs against the folk picture of tightening up. Because the sign of the pressure effect depends on the skill's control storage, the manipulation's strength and the performer, a pressure manipulation must be checked on the outcome before any intervention effect can be read as protection; a null in the control arm leaves the protective contrast undefined.

Granted tier: PROBABLE, set by the code gate on October 4, 2026 (the writer claimed FORGED) · Refuted by the adversary on a step in the reasoning · Sources: 3 cited, 3 opened and confirmed

• adversary REFUTED the claim
• citations: refetched 100% (>=90%), resolved 100% (>=80%) -> OK
• EARNED PROBABLE: one of {grounded cross-lab adversary, verified sources} but not both
• CLAMPED: claimed FORGED -> granted PROBABLE (gate lowers, never raises)

S10 (experts' accuracy rose with pressure, effort and heart rate partial mediators, grip force down); S2 (skilled players: speed up, no deterioration, interaction null, authors concede no choke); S1 (juniors: control arm fell, interaction p=.003). Observation: the directions and p values. Inference: the no-induction-no-inference rule.

• S10Cooke, Kavussanu, McIntyre, Boardley and Ring 2011, Effects of competitive pressure on expert performance: underlying psychological, physiological, and kinematic mechanisms (Psychophysiology; Europe PMC record)opened, quote confirmed50 expert golfers, three pressure levels; pressure increased putting accuracy, anxiety, effort and heart rate and decreased grip force; effort and heart rate partially mediated the improvement
• S2Mizuno and Masaki 2024, Effects of left-hand contraction on tennis serve performance (Frontiers in Psychology)opened, quote confirmed40 skilled college players 20.0 y; neither group deteriorated under pressure (total-score interaction p=.287); max-score count rose in the contraction group p=.021; ball speed up p<.001 and racket speed up p=.013 in both groups; authors say no choking was induced
• S1Beckmann, Fimpel and Wergin 2021, Preventing a loss of accuracy of the tennis serve under pressure (PLOS ONE)opened, quote confirmed20 right-handed male juniors 17 to 18 y; left-hand dynamic handgrip held serve accuracy while the right-hand group fell under pressure, Phase x Group F(1,18)=11.88, p=.003; only valid serves analysed, velocity unmeasured; anxiety rose p<.001 in both groups

The page may not state or imply an inverted-U or a universal choke; it may say that an expert's output can rise under pressure (S10) and that pressure's sign is measured, never assumed. For the player's own measurements: a pressure drill proves a remedy only when the same drill first shows a measured loss without the remedy.

The no-induction-no-inference law replaces the adjacent article's asymmetric Yerkes-Dodson picture with measured cases: expert golfers putted better under pressure, skilled college servers hit harder under pressure with no score loss, and only the junior study produced a choke in its control arm. The adversary called the protective-claim corollary a logical leap not in the source text; it is a design rule, not a source claim, and the page should state it as such. For the player: a pressure effect has no fixed sign, and a remedy is proven only where a control arm measurably lost accuracy.

Practising under pressure raises later performance under pressure by g=0.67 (95% CI 0.43 to 1.12) after one outlier is removed, across 14 studies and 394 participants from novices to elite athletes and police (S9), with benefit on open and closed tasks and no clear moderator. Quiet-eye training in 22 elite golfers (S20, RCT 11/11) held the final fixation at 2,794 ms versus 1,405 ms under pressure, holed 60 percent versus 36 percent (p<.005), explained 43 percent of performance-error variance and cut 1.92 putts per competitive round while controls did not change. Ten days of adaptive working-memory training in recreational adult club players (S14; 30 recruited, 25 analysed, ages about 32 to 35) raised volley accuracy under pressure (Condition x Group p=.044, ηp²=.165; trained 2.67 to 3.44, controls 2.56 to 2.65) and moved the quiet-eye offset later (p=.006), while controls never deteriorated. Left-hand contraction held serve accuracy in 20 juniors (S1, p=.003) but gave no score interaction in 40 college players (S2, p=.287), and across ten studies the pooled g=0.59 (0.14 to 1.03) shrinks under trim-and-fill (S19). In every tennis trial the target was prescribed, so the effects are on execution and no opened trial measured shot choice or decision time. Boundary: the populations above; no trial in adult club players beyond S14, none with a match transfer test.

Each remedy changes one part of the control system: pressure practice makes the pressure state familiar so attentional control is less disturbed by it; a long final fixation keeps attention on the external target and stabilizes the temporal envelope of the stroke; working-memory training raises the capacity that outcome worry would otherwise consume; a left-hand contraction is proposed to damp verbal-analytic control. Because each acts on execution within a given task, its effect is local to that task, population and manipulation check, and transfers to shot selection only by assumption.

Granted tier: PROBABLE, set by the code gate on October 4, 2026 (the writer claimed FORGED) · Refuted by the adversary on unverifiable-unsupported · Sources: 6 cited, 6 opened and confirmed

• adversary REFUTED the claim
• citations: refetched 100% (>=90%), resolved 100% (>=80%) -> OK
• EARNED PROBABLE: one of {grounded cross-lab adversary, verified sources} but not both
• CLAMPED: claimed FORGED -> granted PROBABLE (gate lowers, never raises)

S9 (pressure training g=0.67 after outlier removal, n=394); S20 (elite golfers, QE 2,794 vs 1,405 ms, 60 vs 36 percent holed, 1.92 putts per round); S14 (recreational adults, volley accuracy interaction p=.044, QE offset p=.006); S1 and S2 (handgrip: positive in juniors, null interaction in college players); S19 (handgrip meta g=0.59, weakened by trim-and-fill). Observation: the effect sizes and intervals. Inference: that every effect is execution-local and induction-gated.

• S9Low, Sandercock, Freeman, Winter, Butt and Maynard 2021, Pressure training for performance domains: a meta-analysis (Sport, Exercise, and Performance Psychology 10(1))opened, quote confirmed14 studies (10 sport, 4 law enforcement), n=394; after one outlier removed g=0.67, 95% CI [0.43, 1.12], I²=17.1%; benefit for novice and experienced on open and closed tasks; no clear moderators
• S20Vine, Moore and Wilson 2011, Quiet eye training facilitates competitive putting performance in elite golfers (Frontiers in Psychology)opened, quote confirmed22 elite male golfers (handicap 2.78), RCT 11/11; under pressure QE-trained held QE 2,794 ms vs 1,405 ms, holed 60 percent vs 36 percent (t(20)=3.75, p<.005); QE duration explained 43 percent of performance-error variance; 1.92 fewer putts per competitive round, controls unchanged
• S14Ducrocq, Wilson, Vine and Derakshan, Adaptive working memory training reduces the negative impact of anxiety on competitive motor performance (JSEP; accepted manuscript PDF)opened, quote confirmed30 recreational club players recruited (ages about 32 to 35 y), 25 analysed; 10 days adaptive dual n-back vs 1-back control; volley accuracy Condition x Group F(1,23)=4.535, p=.044, ηp²=.165, trained group 2.67 to 3.44, controls 2.56 to 2.65 (no deterioration); QE offset interaction p=.006; QE duration interaction null
• S1Beckmann, Fimpel and Wergin 2021, Preventing a loss of accuracy of the tennis serve under pressure (PLOS ONE)opened, quote confirmed20 right-handed male juniors 17 to 18 y; left-hand dynamic handgrip held serve accuracy while the right-hand group fell under pressure, Phase x Group F(1,18)=11.88, p=.003; only valid serves analysed, velocity unmeasured; anxiety rose p<.001 in both groups
• S2Mizuno and Masaki 2024, Effects of left-hand contraction on tennis serve performance (Frontiers in Psychology)opened, quote confirmed40 skilled college players 20.0 y; neither group deteriorated under pressure (total-score interaction p=.287); max-score count rose in the contraction group p=.021; ball speed up p<.001 and racket speed up p=.013 in both groups; authors say no choking was induced
• S19Luan, Wang, Keil, Ehrlenspiel and Mirifar 2024, A systematic meta-analysis of the effectiveness of (left) hand contractions on motor performance (Sport, Exercise, and Performance Psychology; Europe PMC record)opened, quote confirmed10 studies; pooled g=0.59, 95% CI [0.14, 1.03]; trim-and-fill correction: the effect may not be as robust as it first appeared; study quality limits the evidence

The page may state that performance under pressure can be trained, with S9 and S20 as rows and the bound that the evidence is on executing a prescribed target. For the player: the levers with controlled effects are practising under a pressure he can measure, holding the final fixation on the target, and (in adults like him) working-memory training on a volley task; none of these has shown a faster or better shot choice.

The countermeasure law carries the dated effect sizes with their populations: pressure practice helps novices and experienced performers, quiet-eye training held elite golfers' putting under pressure, ten days of working-memory training raised recreational adults' volley accuracy under pressure, and the left-hand squeeze helped juniors, did nothing in college players and shrinks under bias correction. The adversary's bound is adopted: none of the opened trials measured shot choice or decision time, which should read as none opened rather than none. For the page: each remedy is local to its task and population and licenses no claim about faster or better selection.

A 30-minute Stroop task with no physical load lowered groundstroke targeting in 66 male players aged 24.3 ± 2.5 against both a placebo and a control condition (p<.001, η²=.20) while raising Stroop time and errors (p=.001, η²=.20), in a randomized placebo-controlled crossover (S13). Physical fatigue at 90 percent of peak heart rate cut groundstroke accuracy from 24.81 to 14.81 percent in 13 experts (LTA 6.2) and from 16.62 to 8.38 percent in 17 non-experts (LTA 10.2), moderate fatigue at 70 percent changed nothing, and the fatigue x expertise interaction was not significant (S5): experts kept a higher level and lost as much. Pressure draws on the same attentional account and the same execution, so a third-set pressure point sits on a baseline already lowered by an unknown amount; a pressure finding from fresh players transfers to a fatigued player only with the fatigue state measured. Boundary: adult male players (S13, within-person), college-age experts and non-experts (S5, within-person); no study crosses pressure with fatigue in tennis.

Attentional control is a shared, depletable resource: a sustained cognitive load lowers it without touching the muscles, and high-intensity physical work lowers stroke accuracy through neuromuscular and perceptual decrement. Because pressure's first effect is also on attentional control (efficiency before effectiveness), an unstated fatigue state confounds the pressure contrast: the same manipulation produces a different loss on a depleted baseline, and expertise does not shield the baseline from physical fatigue.

Granted tier: PROBABLE, set by the code gate on October 4, 2026 (the writer claimed FORGED) · Refuted by the adversary on a step in the reasoning · Sources: 2 cited, 2 opened and confirmed

• adversary REFUTED the claim
• citations: refetched 100% (>=90%), resolved 100% (>=80%) -> OK
• EARNED PROBABLE: one of {grounded cross-lab adversary, verified sources} but not both
• CLAMPED: claimed FORGED -> granted PROBABLE (gate lowers, never raises)

S13 (mental fatigue alone lowers groundstroke targeting, η²=.20); S5 (high-intensity fatigue cuts accuracy in experts and non-experts alike, interaction NS). Observation: the percentages and p values. Inference: the shared-account rule linking pressure and fatigue.

• S13Öztürker and Erman 2025, Impact of mental fatigue on tennis players' attention and groundstroke performance (Frontiers in Psychology, 2025-05-02)opened, quote confirmed66 male players 24.3 y, randomized placebo-controlled crossover; a 30-minute Stroop task raised Stroop time and errors (p=.001, η²=.20) and lowered groundstroke targeting against control and placebo (p<.001, η²=.20)
• S5Lyons, Al-Nakeeb, Hankey and Nevill 2013, The effect of moderate and high-intensity fatigue on groundstroke accuracy in expert and non-expert tennis players (JSSM 12:298-308)opened, quote confirmed13 experts and 17 non-experts; groundstroke accuracy at rest/moderate/high fatigue experts 24.81/25.00/14.81 percent, non-experts 16.62/16.18/8.38 percent; no fatigue x expertise interaction (p>.05)

Any page sentence about holding up late in a match must name fatigue as its own cause with S5 and S13 as rows, never fold it into nerves. For the player: a pressure test of a stroke is read only with the fatigue state recorded (heart rate or a rating), and a mental load before play lowers accuracy on its own.

The fatigue law makes a pressure claim conditional on the body's state: a purely mental load lowered groundstroke targeting in adult players, hard physical fatigue roughly halved groundstroke accuracy in experts and non-experts alike with no protective interaction for expertise, and moderate fatigue changed nothing. The adversary called the undefined corollary an extrapolation; the page should state it as a measurement requirement, that a third-set pressure finding needs the fatigue state recorded, not as a law of nature.

Across 16 studies of 1,794 players aged 12 to 32 (600 elite, 1,194 sub-elite; S7), elite players exceed sub-elite on lower-extremity power (SMD 0.53), endurance (0.59), agility (0.54), speed (0.35) and most of all stroke velocity (SMD 1.00, large): at the good-to-elite boundary the physical difference is real and the biggest single effect is in the ball the stroke produces. Experts also pick up cues more accurately and faster (S8, 42 studies, 388 effect sizes), so a cognitive and a physical gap coexist in the same co-selected bodies. Laboratory perceptual-cognitive training gains transfer to the court at ES 0.65 (0.15 to 1.16) against 1.51 (0.98 to 2.05) in the laboratory (S15, 22 studies, team sports), so the field 'decision' construct already carries movement and execution. Under match pressure, winning professionals were as susceptible to pressure and prior errors as losing ones across 650,000 points (S16), the opposite of a gap carried by pressure resistance at that level. Attributing a level difference to decision speed under pressure would require a condition x level interaction on a choice measure, mediation through it, and physical equivalence shown at a stated precision; no opened source supplies any of the three. An NTRP computer rating adjusts on match outcomes against expected outcomes and 'not how well someone can hit their strokes or play points in a lesson' (S21), so a rating difference cannot name the component that moved. Boundary: elite vs sub-elite 12 to 32 y (S7, cross-sectional), expert vs novice across sports (S8), elite team-sport athletes (S15), touring professionals (S16), USTA league adults (S21); the elite-to-world-class boundary and the adult club boundary are untested in opened rows.

A level is an outcome of co-selected, mutually compensating attributes: earlier recognition buys time, leg power buys reach and racket speed, accepted margin buys safety, and the same shot outcome can be purchased with any of them inside one ballistic budget. A comparison of levels therefore estimates a partial derivative in a system where the inputs covary and are jointly selected; without exogenous variation in one input, or a condition x level interaction with mediation, the attribution is not identified, and a rating that aggregates match outcomes against expectation removes the component information entirely.

Granted tier: PROBABLE, set by the code gate on October 4, 2026 (the writer claimed FORGED) · Refuted by the adversary on a number larger than the sources support · Sources: 5 cited, 5 opened and confirmed

• adversary REFUTED the claim
• citations: refetched 100% (>=90%), resolved 100% (>=80%) -> OK
• EARNED PROBABLE: one of {grounded cross-lab adversary, verified sources} but not both
• CLAMPED: claimed FORGED -> granted PROBABLE (gate lowers, never raises)

S7 (elite vs sub-elite SMDs, stroke velocity 1.00); S8 (expert perceptual-cognitive advantage on accuracy and response time); S15 (lab-to-court transfer 1.51 vs 0.65); S16 (winners as pressure-susceptible as losers); S21 (a rating moves on match outcomes, not components). Observation: the SMDs, the effect-size pair, the susceptibility result, the USTA rule. Inference: refutation of the physical exclusion and non-identification of the attribution.

• S7Lambrich and Muehlbauer 2022, Physical fitness and stroke performance in healthy tennis players with different competition levels: a systematic review and meta-analysis (PLOS ONE)opened, quote confirmed16 studies, 1,794 players (600 elite, 1,194 sub-elite), 12 to 32 y; SMD favouring elite: lower-extremity power 0.53, endurance 0.59, agility 0.54, speed 0.35, stroke velocity 1.00
• S8Mann, Williams, Ward and Janelle 2007, Perceptual-cognitive expertise in sport: a meta-analysis (JSEP 29:457-478; Europe PMC record)opened, quote confirmed42 studies, 388 effect sizes (point-biserial); experts better than non-experts on response accuracy and response time, with fewer, longer fixations and longer quiet eye; paradigm and modality moderate the effect
• S15Zhu, Zheng, Liu, Guo and Cao 2024, Effects of perceptual-cognitive training on anticipation and decision-making skills in team sports: a systematic review and meta-analysis (Behavioral Sciences)opened, quote confirmed22 studies, 45 effect sizes, elite team-sport athletes; task-specific accuracy ES 1.51 [0.98, 2.05] vs on-court transfer accuracy ES 0.65 [0.15, 1.16]; task response time ES -0.91 [-1.45, -0.38] vs on-court -0.44 [-0.81, -0.06]
• S16Harris, Vine, Eysenck and Wilson 2021, Psychological pressure and compounded errors during elite-level tennis (Psychology of Sport and Exercise; Semantic Scholar record)opened, quote confirmedMore than 650,000 points across 12 Grand Slams 2016 to 2019; a 1-to-5 pressure index raised the probability of a double fault or unforced error (ps<.001); a prior-point error OR 1.2 [1.17, 1.23]; multiplicative; winning players as susceptible to pressure and prior errors as losing players
• S21USTA, NTRP ratings FAQopened, quote confirmedA computer rating compares the actual match outcome with the expected outcome from the players' dynamic ratings and adjusts up or down; ratings are based on matches, not how well someone can hit their strokes or play points in a lesson

The page's two sentences are rewritten: 'not physical' is dropped (S7 refutes it where it is testable); 'decision speed under pressure' becomes a stated hypothesis beside the physical difference, with S7, S8 and S16 as rows and the three identification conditions named as open. The 5.0 NTRP figure stays as a goal in his words, with S21 saying what a rating measures. For the player: his own gap to a 5.0 is not assignable to one factor from any opened evidence; a measured plan tracks stroke velocity, movement and decision quality under pressure separately.

The attribution law is the verdict on the page's gap sentence: elite players exceed sub-elite players physically across sixteen studies with the largest effect in stroke velocity, winning professionals were as pressure-susceptible as losing ones, laboratory cognition reaches the court at less than half its laboratory effect, and a rating adjusts on match outcomes against expectation and names no component. The adversary's bound is the one that matters for this owner: the physical refutation holds at the elite-versus-sub-elite boundary in the sampled ages and says nothing measured about two adult club levels, which is where the page's good and great actually live, so for his own level pair the exclusion is unmeasured rather than refuted. The three identification conditions (a condition-by-level interaction on a choice measure, mediation through it, physical equivalence at stated precision) are met for no pair of levels.