Effects Of Prior Sport Participation On Drop Landing Mechanics In Us Army Trainees

Landing activities are associated with musculoskeletal injury (MSKI) during Basic Combat Training (BCT). This may be related to sub-optimal landing mechanics, such as landing with higher impact or less knee flexion, which have been associated with MSKI. As athletes have shown more favorable landing mechanics compared to non-athletes, trainees who participated in sports prior to BCT may show more optimal landing mechanics compared to their non-sports participating trainee counterparts. PURPOSE: To compare drop landing mechanics between trainees with and without prior sports participation. METHODS: 528 Army trainees participated during the first week of BCT. Participants completed three trials of 18” double- and 12” single-leg drop landings. Peak vertical and resultant tibial accelerations were measured with accelerometers. Two-dimensional knee flexion (KF) angles were measured with high-speed cameras and a deep learning-based application for automated feature detection. KF variables included: initial contact and peak angles, and initial landing and total excursion. Participants were grouped as those with/without self-reported competitive experience in sports with multi-axial (M-A) movements, as well as those with/without self-reported experience in sports with frequent jump-landings. ANCOVAs were used to compare dominant leg landing mechanics between groups, controlling for sex and physical activity levels. RESULTS: The M-A sport group was found to have higher KF excursion during initial loading (Figure 1; difference = 1.5°, F = 4.2, p = 0.04). All other main effects were non-significant. CONCLUSION: Trainees with a history of competitive sports participation did not show widespread differences in landing mechanics. This suggests that sport participation may not be the predominant factor in determining whether Army trainees show more optimal landing mechanics associated with reduced MSKI risk. Supported by US DoD award W81XWH-20-C-0123 P0001. The opinions/assertions in this manuscript are the private views of the authors, not to be construed as official policy or reflecting the views of the US Army.