Every contradiction and tension found across the corpus. Individual paper pages carry these inline; look for CONTRADICTION: and TENSION: to find them in context.
A note on the word “contradiction”. Some of these are genuine reversals where a later result overturns an earlier one. Others are two findings that only look opposed until you notice they were measured at different instants, on different people, or under different definitions. Both are recorded, and each is labelled. Where a tension is the cataloguer’s characterisation rather than something an author claims, that is stated.
Tier 1 — Contradicts established coaching orthodoxy
These are the ones that change what you teach.
1. The mixed action does not predict lumbar bone stress injury
Alway, Felton et al. (2021), MSSE — 50 elite male bowlers, prospective, MRI-confirmed.
Shoulder counter-rotation: 43 ± 14° (injured) vs 40 ± 20° (uninjured), not significant. Pelvis–shoulder separation at BFC: 21 ± 15° vs 13 ± 24°, not significant. The injured group averaged above the 30° “mixed action” threshold from Portus et al. (2004) that has driven UK and Australian coaching since the 1990s — and it did not separate them from the bowlers who stayed healthy.
The paper’s own conclusion: “Coach education should incorporate these findings and move away from using far removed derivatives to inform practice which are not consistent with predicting LBSI injury.”
What replaces it: rear hip angle at back foot contact and lumbopelvic angle at front foot contact — 88% classification accuracy.
2. Excessive contralateral trunk side flexion runs the opposite way to the received account
Bayne et al. (2016) and Ranson et al. (2008) linked excessive contralateral thoracolumbar side flexion to injury. Alway et al. found injured bowlers were significantly less contralaterally side flexed at the thoracolumbar joint at release (163 ± 4° vs 160 ± 3°, large effect). Both groups reach similar total lean; the injured group sources more of it one joint lower, at the lumbopelvic junction adjacent to where the fractures occur (p = 0.09, d = 0.57 — the paper’s weakest number, and inferred).
3. Ground reaction force does not independently cause the injury
No GRF measure differed between injured and uninjured — peak vertical ~6.9 vs 6.8 bodyweights, plus horizontal, loading rates and impulses, all non-significant. Coaching a “softer” front foot landing is not supported as an injury intervention. Nor is pace: release speed 35.1 vs 35.8 m/s, non-significant. A fast bowler is not at risk because they are fast.
4. Injured adolescents had more bone, not less
Keylock, Felton et al. (2022) — counter-intuitive and worth sitting with. Alongside it: every prospective injury occurred at 17 or 18 (80 per 100 bowlers/year at 18; zero at 14–16), driven by chronological age (g = 1.396) rather than skeletal age (g = 0.274). And peak 7-day workload discriminated (229 vs 165 balls) where season totals did not — it’s the spike, not the volume.
5. Front-leg bracing is unsupported wherever it was actually measured outside fast bowling
In spin bowling and in batting the front knee flexes. The braced-front-leg principle is a fast-bowling finding that coaches have generalised; nothing in the spin or batting work supports it.
6. Finger spin and wrist spin invert
From the unpublished elite wrist-spin study in the Sanders (2019) thesis: pelvis and shoulder orientation at release carry opposite signs between the two (wrist spinners: less shoulder rotation, shoulders short of chest-on at release, r = −0.837 and −0.875). Transferring finger-spin coaching to a leg-spinner is actively wrong, not merely unhelpful.
Tier 2 — Felton contradicting Felton
7. The strength conclusion flipped between conference and journal
Same 10 models, same manipulation, one year apart.
- 2024 (ISBS): increased strength “facilitates a greater delay in bowling arm circumduction”; ball speed 40.7 → 41.1 m/s (+0.8%).
- 2025 (J Sports Sci): no significant joint-angle differences at all, with trends toward less knee extension, less trunk flexion, more shoulder extension — described as “contrary to expectations”. Ball speed 40.7 → 41.5 m/s (+2.0%).
The journal version closes with a warning against using strength training to change technique. The changed ball-speed figures are not acknowledged. The journal version supersedes.
8. Felton contradicts his own PhD on what strength buys you
The thesis and the 2015/2017 conference papers argued strength lets the front leg stay straighter. The 2025 paper found the opposite trend. The founding intuition did not survive his own later modelling.
9. Rear hip flexion timing reversed, unacknowledged
2020 optimisation wants it earlier; 2023 wants it later. Same model, same lab.
10. The individual-specific thesis, partially reversed
2017 argued optima are individual, so general technical models mislead. The two 2023 papers found genuine commonalities across elite bowlers. Resolution: the direction of the optimum is shared; the attainability is individual. Worth stating carefully rather than as a flat reversal.
11. “The 22%” vanished from the record
The thesis and 2015/2017 conference papers headline 21.5–22% of ball speed attributable to landing position. That figure never enters the peer-reviewed record — 2020 reports 9.8%, and the published group equivalent in 2023 is 13.5%. If you have seen 22% quoted, it comes from unrefereed work.
12. Both 2023 papers overclaim ground reaction force in their abstracts
Abstracts say optimal technique produced “lower peak ground reaction forces”. Their own tables show p = 0.39 and p = 0.09. Only loading rates were significant. Read the tables.
13. Elbow hyperextension: free speed, or an injury pathway?
2016 sells it as worth ~0.2% ball speed per degree (≈5%, ~5 mph, at 20°) and ICC-legal. 2025 finds increased strength drove hyperextension to every bowler’s ceiling and warns of posterior elbow impingement and bone stress injury. The same mechanism, framed as an asset and then as a hazard.
14. Does impact shock even cause the lumbar injury?
Every Lamb paper opens by framing impact shock as the risk mechanism — then the 2023 ISB paper concludes the elastic wave is “unlikely to contribute to lumbar stress fracture risk.” This undercuts the premise of the ECB-funded workload-monitoring line it belongs to.
15. The student critiques the supervisor
All three Lamb papers name Felton, Yeadon & King (2020) as performance-only and argue rigid pin-jointed models are unsuitable for internal loading. That critique is the explicit motivation for Lamb’s compliance model — and it is correct.
16. The 2021 review criticises Felton’s own model parameters
His 2019 model allowed 4.5–10 cm of wobbling-mass movement (up to 56 mm in simulation); the 2021 review cites measured soft-tissue displacement of 1.4 cm and heel/shoe deformation of 11.5–12.7 mm. A self-acknowledged weakness in exactly the parameters that generate the force numbers. (Characterisation: the review presents this as honest self-critique, not as a conflict.)
17. The planar-model story was materially revised
2016 called the method “suitable” while reporting no plain-planar baseline. 2019 supplied the baseline and showed the unmodified assumption was substantially inadequate (18% force error, 23% vertical). Not a reversal, but quote 2019’s numbers, not 2016’s framing. Separately, 2019 calls 3D “non-viable” and planar the solution, while the 2021 review reframes 2D as a temporary stopgap.
18. Power hitting: the separation plane flipped between conference and journal
Conference: frontal plane. Journal: transverse plane. Rear elbow extension went from “very strong” to non-significant (p = 0.086). The journal wins — it covaries out height and mass, and the males were +12 cm and +12 kg on the females.
Tier 3 — Contradictions in the female-bowling line
Three studies, small samples, and several straight reversals. Treat this whole area as unsettled.
19. Arm timing: earlier or later?
2015 conference: faster women had earlier circumduction (measured at FFC). Lyons 2023: a more delayed arm is the top predictor (measured at BR, r = 0.95, 89% of variance in 11 bowlers, 0.224 m/s per degree). Different instants — so possibly not a true contradiction, but they yield opposite coaching cues and no one has reconciled them.
20. Front knee: straighter or more flexed?
2015: more flexed at BR in the faster women. Lyons 2023: straighter at FFC (r = 0.68). Again different instants. The 2019 paper shows the sexes don’t differ on the mean at all — only on the spread (SD 24.9° vs 18.8°), which is itself interesting: women are more variable here, not different on average.
21. The same 11 bowlers, opposite results
Lyons 2022 poster vs Lyons 2023 journal. Run-up speed: non-significant on the poster, r = 0.75, p = 0.01 in the journal. Front knee at FFC: non-significant → r = 0.68. Same cohort. The journal version should be preferred, but the reversal is unexplained.
22. Trunk flexion is male-only
A pillar of the male ball-speed model. In women: r = −0.19, p = 0.57, despite a 33° spread across the sample. Not a small effect — no effect.
23. “Run in faster” fails upstream
Pre-bound run-up speed predicts arrival speed at back foot contact at r = 0.844 but ball speed at r = 0.262 (n.s.). The speed gets to the crease and then stops being useful. In women, run-up speed correlates at r = 0.75 — but collapses to r = 0.41 (n.s.) once height is controlled.
Tier 4 — Internal tensions with no resolution
24. The front leg: speed versus shock
The central unresolved trade-off in fast bowling. A braced, straight front leg produces more ball speed (Felton, Yeadon & King 2020). A compliant front leg attenuates shock (all three Lamb papers; causally confirmed in simulation — stiffen the leg 100× and shank acceleration goes 76 → 197 g).
Do not oversell this. At a plausible 10× stiffening, the rise at L5 is only +5%. At 100×, the shank rises +158% while L5 rises +43% — stiffening hurts the leg’s own protection far more than it loads the back. Unresolved anywhere in Felton’s output, and the simulation that could price the exchange rate was promised at ISCSB 2023 and never published.
25. Trunk rotation both builds bone and marks the injured
The same trunk rotation that best predicts high lumbar bone mineral density is also significantly greater in the injured group. Adaptation and damage may be the same signal at different doses.
26. Thoracic flexion does two jobs
More flexion → more ball speed (Worthington 2013) and → shorter length (Manawadu). Coach it for pace and length may creep short. Raised in the Manawadu thesis and never investigated.
27. Spin rate versus legality
Spratford’s advice for reducing elbow extension — be more side-on — is exactly what lowers spin rate. Sanders flags this himself. A bowler cleaning up a suspect action should expect to lose revolutions.
28. Attenuation beyond L5
Lamb finds shock attenuation continues L5 → L1 → C7 (p < 0.01); McErlain-Naylor, King & Allen (2021) found none beyond L5 in drop landings. McErlain-Naylor co-authors both.
29. Optimal technique — does it raise or lower front-foot load?
Depends on whether the landing position was also optimised. Never reconciled within the simulation cluster.
30. The review’s own robustness standard isn’t met by the cricket work
The 2021 review says optima must be robust to perturbation, and admits uptake “has been sporadic”. The cricket optimisations are single-best-performance optima. Related: the review praises in-vivo dynamometry for giving “assurance” that torques are realistic, while Parkinson (2022) shows single-angle protocols can be 30–96% wrong. Felton used multi-angle, so his work is fine — but the review’s reassuring framing should not be transferred to studies that didn’t.
31. Objective function determines the answer
In gymnastics, minimising joint torque diverged from what the elite athlete actually did; maximising success under variability converged on them. Always ask: optimal for what?
32. Bound take-off angle has no single right answer
Bull et al. (2026): a lower take-off angle gives more speed at BFC and a better front-leg plant angle; a higher angle gives a straighter front knee at release. No angle optimises both. Any squad-wide bound instruction is wrong for someone. The authors call their own result “conflicting” and resolve it as non-linear.
33. Hip internal rotation points three different ways
Across three studies in the injury cluster, hip internal rotation findings do not align. No resolution offered.
34. Sex differences in batting may be adaptation, not fault
All 15 male batters extended the lead elbow (30 ± 12°); 8 of 15 female batters flexed it. The authors explicitly decline to call this a fault — it may be a rational response to shorter boundaries, different bat moment of inertia, or strength. And the 78%-of-bat-speed model is male-only: whether those variables predict distance within female batters has never been tested.
Reporting errors recorded (so nobody chases them)
Numerical inconsistencies found inside published papers. Details in the individual paper pages.
- Sanders thesis: elbow extension reported as both 3.65 ± 3.24° and 10.6 ± 6.1° for the same 23 bowlers. This one matters — one figure sits near the 15° legal limit and the other doesn’t. Also 34 vs 36 bowlers; deviation-angle optimum given as both “>±7°” and “±2°”; a 43.1%/42.9% text-vs-table swap.
- Bull et al. (2026): shoulder correlation 0.379 (text) vs 0.064 (table); pelvic-tilt sign given as both +0.716 and −0.716. Tables preferred.
- Lyons 2023: text says “knee angle at BR” where every table says FFC.
- Manawadu: yorker release angle 2.2 ± 0.9° (table) vs 1.9 ± 1.8° (text); bouncer success 98.7% vs 98.3%; shoulder regression 45.6% vs 45.3%.
- Lamb 2022 (ISBS): a self-contradictory significance sentence.
- Lyons 2022 poster: title claims “kinetic” variables; no kinetics were measured.
- Alway 2018 and Alway 2023 are the same study, published twice — same 20 bowlers, same numbers, same closing sentence. Filed with a pointer rather than double-counted.
- Felton 2016 (ISBS): a typographical slip (“may result in a simulation model providing insights”) where the restrictive reading is plainly intended.
- The 2019 power-hitting conference URL on drpaulfelton.com returns HTTP 404; recovered from the first author’s site.
- Manawadu’s thesis title over-promises: “A Biomechanical Analysis of Fast Bowling Variations” is pitch length only — nothing on slower balls, cutters, swing or seam position.