827 US Military Academy cadets followed through 9 weeks of basic training: the longest ground contact times (>0.42 s) went with 2.15× the risk of overuse lower-extremity injury after adjustment, the shortest stride length with 45% more overuse injury (univariate), and foot strike pattern and cadence were not associated with injury
Before cadet basic training, stride length, ground contact time, cadence and foot strike pattern were recorded in incoming cadets; lower-extremity musculoskeletal injuries over the 9 weeks of training were documented and analysed as time to injury.
Participants
n=827 incoming cadets, class of 2020, United States Military Academy.
Protocol
Baseline running spatiotemporal measures and foot strike analysis; demographics as covariates.
Outcome: lower-extremity injury with ≥3 days of activity limitation over 9 weeks; Kaplan-Meier and multivariate Cox models.
Key Results
Adjusted: the longest contact times (>0.42 s) carried a higher risk of overuse lower-extremity injury than the shortest (<0.28 s): HR 2.15 (95% CI 1.06-4.37).
About 18.1% sustained a lower-extremity injury with ≥3 days of limitation.
Univariate: shortest stride length (<133.0 cm) vs longest (>158.5 cm) — 39% more likely any injury, 45% more likely overuse injury; longest contact time twice as likely any injury.
No significant difference in injury risk by foot strike pattern or cadence.
Practical Application
Foot strike pattern and cadence did not predict injury here; this does not support changing either to prevent injury in a new trainee.
Inference: long contact time and short stride may mark lower fitness or slower running rather than a technique fault to coach; the abstract does not test this.
Limitations
9-week follow-up in military basic training (Inference: marching, mixed loads); transfer to recreational runners is uncertain.
Stride length finding is univariate; the abstract does not say how foot strike was classified or the split of strike patterns.
Running speed at testing is not given in the abstract.
How this entry was checked and changed
Why this level
prospective, large, adjusted for sex, prior running volume and injury history; short follow-up and a military setting