2026 — The Pre-Delivery Stride (the "bound" / "gather") and What It Does to the Delivery

Source note: full open-access article read, including Tables 1–3. All numbers below are transcribed directly.

Research theme

Fast bowling research has essentially started the clock at back foot contact. Everything before that — the bound, the gather, the jump, the penultimate step — has been left to coaching folklore. This is the first study to ask what the pre-delivery stride actually does to the technique that follows it. 29 elite male fast bowlers (age 22.46 ± 3.78 yr, height 1.86 ± 0.07 m, mass 85.15 ± 10.66 kg), retrospectively pulled from the historical Loughborough dataset that also produced Worthington et al. (2013) and Alway et al. (2021), each bowling maximal-velocity good-length deliveries indoors on a full-length artificial facility, 18-camera Vicon at 300 Hz, 47 markers, fastest clean trial per bowler analysed. Six pre-delivery-stride characteristics were correlated (Pearson/Spearman, α = 0.05) against eight performance-related and eight lumbar-bone-stress-injury-related delivery characteristics. An a priori power analysis (r = 0.5, α = 0.05, power 0.8) set n = 29. Exploratory; no hypothesis. Correlational and cross-sectional — it shows which bound characteristics travel with which delivery characteristics, not that changing one changes the other.

What they measured

Pre-delivery stride (the bound):

• How high the bowler’s mass centre rises in the bound (jump height, absolute and as % of standing height)
• How long the bound is (penultimate step length, absolute and as % of standing height)
• How fast the bowler is running just before jumping into the bound (run-up velocity pre-jump)
• How hard the bowler is coming down onto the back foot (vertical COM landing velocity at back foot contact)
• How steeply the bowler launches into the bound (take-off angle of the COM relative to horizontal at penultimate step take-off)
• Whether the pelvis is tipped forward at take-off (pelvic tilt at penultimate step take-off; <180° = anterior tilt)

Performance side (from Worthington 2013, King 2016, Ferdinands 2010):

• Ball release speed; run-up velocity at back foot contact; front leg plant angle at front foot contact; front knee angle at ball release; thoracolumbar (trunk) flexion FFC→BR; bowling shoulder angle at FFC; mean COM acceleration through the back-foot and front-foot phases

Injury side (the eight from Alway et al. 2021):

• Front hip angle at FFC; pelvic tilt at FFC; thoracolumbar rotation at BFC; lumbopelvic angle at FFC; rear hip angle at BFC; rear knee angle at BFC; thoracolumbar side flexion at BFC and at BR

Findings

Sample descriptives (Table 1)

1. Ball release speed 35.4 ± 1.33 m/s (32.7–38.5). Jump height 1.27 ± 0.07 m absolute, 68.0 ± 3.80% of standing height (60.4–76.5%). Penultimate step length 2.27 ± 0.32 m, 122 ± 18% of standing height (92.2–162%). Run-up velocity pre-jump 6.00 ± 0.60 m/s (4.71–7.26). Landing velocity at BFC −1.42 ± 0.30 m/s (−1.99 to −0.89). Take-off angle 11 ± 3° (5–17°). Pelvic tilt at take-off 174 ± 8° (155–195). Front leg plant angle at FFC 38 ± 4° (27–44). Run-up velocity at BFC 5.87 ± 0.53. Front knee angle at BR 177 ± 17° (133–196). Trunk flexion FFC→BR 31 ± 7°. Rear hip at BFC 147 ± 13°, rear knee at BFC 151 ± 13°.
2. Fifteen significant correlations were found overall.

The headline null 3. Ball release speed was not correlated with ANY pre-delivery stride characteristic (r = −0.134 to 0.260, p = 0.170–0.984). The bound does not directly predict how fast you bowl. What it predicts is the technique you arrive in.

Performance-related links (Table 2 — nine significant) 4. Run-up velocity before the jump → run-up velocity at back foot contact: r = 0.844, p < 0.001. Much the strongest relationship in the study. But it is not 1.0 — meaning bowlers differ meaningfully in how much speed they lose across the bound. That loss is the coachable bit. 5. Take-off angle → run-up velocity at BFC: r = −0.400, p = 0.032. The steeper the launch into the bound, the slower the arrival at back foot contact. 6. Penultimate step length (normalised) → run-up velocity at BFC: r = 0.505, p < 0.001. Longer bound, faster arrival. 7. Pre-jump run-up velocity → front leg plant angle at FFC: r = 0.524, p = 0.004. Faster in, front foot planted further ahead of the hips (larger plant angle — previously linked to greater braking impulse). 8. Take-off angle → front leg plant angle at FFC: r = −0.428, p = 0.021. Steeper bound, smaller plant angle. 9. Pre-jump run-up velocity → front knee angle at ball release: r = −0.382, p = 0.041, and penultimate step length → front knee angle at BR: r = −0.436, p = 0.018. Faster run-up and longer bound went with MORE flexed (more collapsed) front knees at release — the opposite of what the male performance literature says is optimal. 10. Pre-jump run-up velocity → mean COM acceleration through the front-foot phase: r = −0.401, p = 0.031 (more deceleration/braking). 11. Landing velocity at BFC → trunk flexion FFC→BR: r = 0.372, p = 0.047. Bowlers dropping harder onto the back foot achieved less trunk flexion through the delivery. 12. Reporting discrepancy in the source: the Results text also claims landing velocity correlated with bowling shoulder flexion at FFC (r = 0.379, p = 0.043), but Table 2 gives that cell as 0.064, unstarred. The table is internally consistent with the abstract’s summary; treat the shoulder claim as unverified.

Injury-related links (Table 3 — six significant) 13. Pelvic tilt at bound take-off → rear hip angle at back foot contact: r = 0.716, p < 0.001. The strongest injury-side relationship in the study. Greater anterior pelvic tilt at take-off went with a more flexed rear hip at back foot contact — and rear hip flexion at BFC is the single most important kinematic predictor of prospective lumbar bone stress injury (Alway et al. 2021). 14. Pelvic tilt at take-off → rear knee angle at BFC: r = 0.447, p = 0.015. Same pattern for the back knee. 15. Landing velocity at BFC → rear hip angle at BFC: r = 0.479, p = 0.009, and → rear knee angle at BFC: r = 0.401, p = 0.031. Coming down harder onto the back foot goes with a more collapsed, more flexed back leg. 16. Jump height (normalised) → pelvic tilt at FFC: r = −0.472, p = 0.010, and take-off angle → pelvic tilt at FFC: r = −0.449, p = 0.014. Jumping higher and launching steeper both went with more anterior pelvic tilt at front foot contact — a position associated with lumbar bone stress injury. 17. The authors’ proposed mechanism for 16: the vertical deceleration from a bigger jump may exceed the pelvic musculature’s capacity to resist anterior tilting at landing. And anterior pelvic tilt at FFC plausibly forces compensatory lumbopelvic extension to keep the trunk upright — and lumbopelvic extension at FFC is the second of the two variables in the Alway et al. (2021) 88%-accurate injury classification model. That is a concrete, coachable pathway from the bound to a stress fracture. 18. Nothing in the bound related to front hip angle at FFC, thoracolumbar rotation at BFC, lumbopelvic angle at FFC, or thoracolumbar side flexion at BFC or BR.

The trade-off the authors draw out 19. There is no single “good bound.” Faster and flatter buys you a faster arrival at the crease and a bigger front-leg plant angle (both good for speed), but costs you front knee extension at release (bad for speed) and, if you land hard, a collapsed back leg (bad for the back). Higher and steeper buys you a straighter front knee at release, but costs run-up speed and drives anterior pelvic tilt at front foot contact (bad for the back). 20. The authors’ conclusion: “individual-specific pre-delivery stride run-up velocities and take-off angles exist to synchronously optimise technique to enhance performance and reduce injury risk,” and the relationships between run-up speed, take-off angle and front leg kinematics are likely non-linear. They suggest these bowlers were on average running in faster than their individual optimum. They also warn that an intervention manipulating run-up speed alone may not work, because a bowler told to run in faster may simply jump higher to buy back the time they need.

What a coach should look for on video

This is the most coachable paper in the cluster: everything here happens before back foot contact, in a phase a coach can isolate, drill, and rebuild without touching the delivery itself.

Cue 1 — Take-off angle: how steeply does the bowler launch into the bound?

• Camera view + frame: Side-on, camera square to the run-up, wide enough to hold the penultimate step through to back foot landing. Scrub to the frame the penultimate foot leaves the ground and track the path of the hips.
• What “good” looks like: Elite men in this study launched at 11 ± 3°, range 5–17° — much flatter than most club bowlers bound. Flatter (lower angle) is associated with a faster arrival at the crease (r = −0.400) and a bigger front leg plant angle (r = −0.428).
• What the fault looks like: A high, springy, “leaping” bound where the hips travel visibly upwards. Above roughly 17° you are outside the elite range entirely.
• Why it matters: Take-off angle is significantly linked to four downstream characteristics — run-up speed at BFC, front leg plant angle, pelvic tilt at FFC — more than any other bound variable except pelvic tilt. And it cuts both ways: too steep loses momentum and drives injury-risk pelvic tilt; too flat may not give the bowler enough air time to organise. It is a bowler-specific optimum, not a target.

Cue 2 — Pelvic tilt at the moment of take-off (the injury cue)

• Camera view + frame: Side-on, pause on the frame the penultimate foot leaves the ground. Look at the line of the belt/waistband.
• What “good” looks like: Pelvis close to neutral. This squad averaged 174 ± 8°, range 155–195° (below 180° = tipped forward).
• What the fault looks like: The belt line tipped forward and down at the front, arse sticking back, lower back arched — the classic anterior-tilt “duck” posture, carried into the air.
• Why it matters: This is the strongest injury-side relationship in the paper (r = 0.716, p < 0.001). A bowler who takes off with an anteriorly tilted pelvis lands at back foot contact with a more flexed rear hip — the single best kinematic predictor of a subsequent lumbar stress fracture. This one frame is arguably the highest-value injury screen in the whole Felton corpus, because it is upstream, visible, and addressable with lumbopelvic control work rather than by rebuilding the action.

Cue 3 — How hard does the bowler land on the back foot?

• Camera view + frame: Side-on, watch the hips through the last third of the flight into back foot contact.
• What “good” looks like: This squad came down at −1.42 ± 0.30 m/s (range −1.99 to −0.89). Softer arrivals sat at the −0.9 end.
• What the fault looks like: A visible thump — the bowler drops into back foot contact, the back knee and hip fold, the hips sink.
• Why it matters: Harder landings went with a more flexed rear hip (r = 0.479) and rear knee (r = 0.401) at back foot contact — both markers of lumbar bone stress injury risk — and with less trunk flexion through the delivery (r = 0.372), i.e. less speed. Landing heavily is the rare cue that costs you on both counts.

Cue 4 — Bound length

• Camera view + frame: Side-on wide, measure the horizontal distance from the penultimate foot at contact to the back foot at back foot contact, and express it as a fraction of the bowler’s height.
• What “good” looks like: 122 ± 18% of standing height (range 92–162%) in this elite squad. So a 1.85 m bowler bounds roughly 2.25 m.
• What the fault looks like: A short, hopping bound (below ~92% of height) is associated with a slower arrival at back foot contact (r = 0.505).
• Why it matters: Longer bound → faster at the crease. But longer bound also went with a more flexed front knee at release (r = −0.436), which costs speed. Genuine trade-off. Use it to diagnose a bowler who bounds far but collapses, or one who hops and arrives slow — not to set a length target.

Cue 5 — Jump height

• Camera view + frame: Side-on, track the rise of the hips through the bound.
• What “good” looks like: Range in this squad was 60.4–76.5% of standing height for the COM position (mean 68.0 ± 3.80%).
• What the fault looks like: A conspicuously high bound.
• Why it matters: Higher jumps went with more anterior pelvic tilt at front foot contact (r = −0.472) — an injury-risk position. Jump height was not related to ball speed, run-up speed at BFC, or trunk flexion. On this evidence a big bound buys nothing measurable and carries a cost.

A cue this paper explicitly kills: do not tell a bowler the bound will make them faster. No bound characteristic correlated with ball release speed at all. The bound shapes the technique you arrive in; it does not directly produce pace.

Caveats and limits

• n = 29 elite males from one nation. The authors flag this as a population bias and say “it is unclear whether these findings hold for differing populations of fast bowlers.” Nothing here has been tested in women, juniors, or club bowlers.
• Correlational, cross-sectional. No intervention. Every “→” above is an association among 29 bowlers, not a demonstrated causal chain. The authors say so directly and call for causal work.
• Only the single fastest clean trial per bowler was analysed (chosen for ecological validity re: maximal performance), so within-bowler variability is not represented.
• Retrospective use of an existing dataset, so the pre-delivery stride variables were chosen from what happened to be in the capture volume.
• No adjustment for multiple comparisons across 6 × 16 = 96 correlations, deliberately, to avoid Type 2 errors. At α = 0.05 you would expect roughly 5 false positives by chance; 15 significant results were found. The strong ones (r = 0.844, 0.716, 0.524, 0.505) are safe; the marginal ones around r = 0.37–0.40, p ≈ 0.03–0.05 should be treated as leads, not facts.
• Findings “describe the group rather than an individual” — the authors’ own words. The whole thrust of the discussion is that optima are individual and the relationships are likely non-linear, so linear r values understate the real picture.
• Collected indoors on artificial turf. Validated as representative by Alway et al. (2024) in this same cluster.
• Internal reporting discrepancies: (a) the Results text gives a landing-velocity → bowling shoulder flexion correlation of r = 0.379, p = 0.043 that does not appear as significant in Table 2 (which shows 0.064); (b) the text gives pelvic tilt at take-off → rear hip angle at BFC as r = −0.716 while Table 3 gives +0.716 — the table sign is the one consistent with the stated interpretation. Prefer the tables.
• Medial-lateral COM velocity during the bound was not examined; the authors name it as future work.

Relationship to other Felton work

• Built directly on the same Loughborough dataset as Worthington, King & Ranson (2013) (the male 74% performance model) and Alway, Felton, Brooke-Wavell, Peirce & King (2021) (the 88% lumbar bone stress injury classification model). Its performance variables come from the first and its injury variables from the second, wholesale.
• Extends Alway et al. (2024) (grass vs artificial, this cluster) by pushing the analysis window earlier rather than outward.
• Cites Felton, McCaig & King (2023) (range of motion vs key technique characteristics) and Felton, Shine, Yeadon & King (2025) (effect of increased strength on ball speed and front-foot-contact technique) — the latter’s finding that stronger bowlers may deliberately increase knee flexion to slow trunk flexion and buy time for upper-body force is used to explain finding 9.
• TENSION (internal to this paper, and the most important one for coaches): faster pre-jump run-up and longer bound produce a larger front leg plant angle at FFC (good, more braking) but a more flexed front knee at ball release (bad, less efficient momentum transfer). The authors call the result “conflicting” in their own discussion. Two variables that the male performance literature treats as pointing the same way — braced front leg, big plant angle — are here driven in opposite directions by the same upstream cause. Their resolution is that the relationship is non-linear and these bowlers were running in above their individual optimum.
• TENSION with the male performance model: Worthington et al. (2013) has run-up speed as the single most important predictor of ball release speed. Here, run-up velocity before the bound predicts run-up velocity at back foot contact superbly (r = 0.844) but predicts ball release speed not at all (r = 0.262, ns), and predicts a worse front knee at release. The “run in faster” cue does not survive contact with the bound.
• CONTRADICTION with the flat-bound coaching cue: a lower take-off angle is good for speed-related variables (faster at BFC, bigger plant angle) but a higher take-off angle is what goes with a straighter front knee at release. There is no take-off angle that optimises both. Any coach applying a single “flatten the bound” or “get more air” instruction across a squad is guaranteed to be wrong for some of them.