2019 — Passive hip and shoulder range of motion, and spin rate, in elite finger spinners

Research theme

The 2018 kinematics paper found that spin rate hinges on how open the pelvis is at front foot contact and ball release. The obvious follow-up: is a bowler’s pelvis position limited by their passive flexibility? This study measured rotational passive range of motion (PROM) at both hips and both shoulders in sixteen elite male finger spin bowlers (a subset of the same ECB-identified elite squad), then correlated those measures against maximum spin rate from ten maximal deliveries recorded on Trackman radar. All PROM measurements were done by one experienced physiotherapist using an inclinometer, before warm-up, in a fixed order. Design is explicitly correlational. It is a screening study, not an intervention — nobody was stretched and re-tested.

What they measured

Twelve measures — internal rotation, external rotation, and total arc (internal + external) for each of four joints:

• Bowling shoulder and non-bowling shoulder, measured lying on the back with the arm out at 90° and the elbow bent 90° (the standard “throwing” position); examiner turns the arm until end of range while holding the shoulder blade down.
• Rear hip (back leg) and front hip (front leg), measured supine with the knee bent 90°; examiner turns the leg until the pelvis starts to lift.
• Ball spin rate (Trackman, rpm) — the maximum of ten maximal-spin deliveries.

Reported reliability for these measures: shoulder IR ICC 0.73, shoulder ER ICC 0.92, hip IR ICC 0.78, hip ER ICC 0.80–0.82.

Findings

1. Spin rate: 1484–1929 rpm (1699 ± 123 rpm) — consistent with the 2018 paper’s 1685 ± 170 rpm.
2. The one PROM measure significantly correlated with spin rate was total rotation arc of the FRONT hip: r = 0.552, p = 0.027, explaining 25.5% of the variance in spin rate. Bowlers with a bigger front-hip rotation arc spun it harder. Group mean 82.8 ± 10.8° (range 67–107°).
3. Internal rotation of the REAR hip was correlated at the relaxed threshold: r = 0.485, p = 0.057. Mean 34.3 ± 8.0° (range 21–50°). It was dropped from the regression because it correlated >0.79 with front-hip total arc — i.e. the two are not independent; bowlers who are open at one hip tend to be open at the other.
4. Internal rotation of the BOWLING shoulder was correlated at the relaxed threshold: r = 0.476, p = 0.063. Mean 77.4 ± 11.7°. More internal rotation available = more spin.
5. Everything else was flat. Notably external rotation of the bowling shoulder was NOT related to spin (r = −0.309, p = 0.245) — despite external rotation being the measure most people fixate on in throwing athletes. Total shoulder arc: r = 0.052. Front-hip internal rotation alone: r = 0.400, p = 0.125. Rear-hip total arc: r = 0.395, p = 0.130.
6. Side-to-side asymmetries (the “throwing shoulder” pattern) were present:
   • Bowling shoulder had more external rotation than the non-bowling shoulder: 137.4 ± 15.7° vs 128.7 ± 13.5°, p = 0.039 (medium effect).
   • Bowling shoulder had less internal rotation: 77.4 ± 11.7° vs 83.1 ± 11.3°, p = 0.089 (small effect).
   • Total shoulder arc was the same both sides (214.8 ± 13.6° vs 211.8 ± 14.2°, p = 0.282). The authors read this as the protective pattern: the range has shifted, not shrunk. In baseball, an asymmetric total arc is the pattern associated with shoulder and elbow injury.
   • Front hip had more internal rotation than the rear hip: 37.6 ± 8.8° vs 34.3 ± 8.0°, p = 0.041 (small effect). Hip external rotation and total arc did not differ side to side.
7. The awkward finding the authors flag themselves: the shoulder adapts toward less internal rotation, but more internal rotation is what goes with higher spin. So the adaptation runs against performance. Their speculation: the shoulder adaptation may come from the huge throwing (fielding) workload of a cricketer rather than from bowling, in which case throwing volume in spinners might need monitoring.

TENSION (internal, minor): the abstract gives rear-hip internal rotation as r = 0.466, p = 0.059; Table 3 gives r = 0.485, p = 0.057. Same conclusion, slightly different figures. Quote the table.

What a coach should look for on video

Be honest with yourself: there are no video cues in this paper. PROM is measured on a physio plinth with an inclinometer, on a passive, relaxed athlete. Nothing here is visible in bowling footage. What this paper gives a coach is an off-field screening and training target, which is arguably more actionable than a video cue.

Screen 1 — Front-hip total rotation arc (the headline)

• How: Athlete supine, test knee bent to 90°, other leg’s foot flat on the bed. Physio (or a competent S&C coach) passively rotates the leg in, then out, stopping the moment the pelvis begins to lift. Inclinometer on the inside of the shin below the knee. Total arc = internal + external. Test the front leg (the leg that lands at front foot contact — the non-bowling-arm side).
• What “good” looks like: The high-spin bowlers in this sample sat at the top of a 67–107° range around a mean of 82.8°. Treat >90° as the comfortable end and <70° as a flag.
• What the fault looks like: A tight front hip that runs out of rotation early and drags the pelvis with it.
• Why it matters: The only significant predictor; 25.5% of spin-rate variance. The mechanism the authors propose links straight to the 2018 paper: without front-hip rotation you cannot get the pelvis to the mid-way position at front foot contact, or past front-on at release — so the technique cue is unavailable to you.
• Video corollary: if a bowler fails Cue 1 or Cue 3 of the 2018 paper on video (hips not opening at FFC, hips not past square at release), check the front hip on the plinth before you coach the position. You may be asking for a movement they physically cannot make.

Screen 2 — Rear-hip internal rotation

• How: Same protocol, back leg.
• What “good” looks like: Mean 34.3 ± 8.0°, range 21–50°; more was better. Flag anything near the low twenties.
• Why it matters: r = 0.485, p = 0.057 (relaxed threshold). Proposed mechanism, borrowed from baseball pitching: you need rear-hip internal rotation to drive the back thigh through and get the pelvis into the right orientation at front foot contact.

Screen 3 — Bowling-shoulder internal rotation

• How: Supine, arm abducted 90°, elbow bent 90°, scapula stabilised; rotate the forearm toward the feet.
• What “good” looks like: Mean 77.4 ± 11.7°; more was better for spin.
• Why it matters: r = 0.476, p = 0.063 (relaxed threshold). Also the tension above — the bowling shoulder naturally drifts away from this.

Monitoring cue (injury, not performance) — total shoulder arc symmetry

• Compare total arc (IR + ER) bowling vs non-bowling shoulder. In this group they matched (214.8° vs 211.8°). A loss of total arc on the bowling side is the pattern linked to shoulder/elbow injury in baseball. Loss of internal rotation offset by gained external rotation is the normal, probably protective, adaptation.

Caveats and limits

• n = 16, all elite males. Only one measure made it into the regression. Three of the six discussed relationships sit at the relaxed p < 0.10 threshold.
• PROM only, and only rotations of hips and shoulders. No thoracic spine, no wrist, no forearm — the authors name this as a limitation.
• Correlational. Nobody was stretched and re-tested. There is no evidence here that increasing front-hip arc raises spin rate.
• PROM is state-dependent — time of day, prior activity, warm-up. Measured pre-warm-up here specifically to control it, but that means these are cold values, and some bowlers gain more from a warm-up than others.
• Single examiner (good for consistency, no inter-rater check within this study). Reliability ICCs quoted are from prior literature (0.73–0.92), not re-established here.
• Spin rate is the maximum of ten, not an average — a single best delivery drives the correlation.
• The shoulder-adaptation-vs-performance conflict is speculation by the authors; the throwing-workload explanation was not tested.

Relationship to other Felton work

• Direct follow-up to Sanders 2018 — kinematic parameters. That paper found front hip internal rotation FFC→BR correlated with spin at r = 0.371 (p = 0.082) and front foot orientation at FFC at r = 0.416; this paper supplies the capacity explanation for both.
• Forms Chapter 6 of Sanders’ 2019 PhD thesis.
• Also presented at the 2019 6th World Congress of Science and Medicine in Cricket (conference version not in this collection).
• No contradictions with other Felton work. The one internal wrinkle is the shoulder adaptation/performance conflict described above, which the authors raise themselves.