A Preliminary Analysis Of The Association Of Gait Mechanics With Musculoskeletal Injury In Army Trainees

Running and ruck marching (walking with load) are the most common activities leading to overuse lower extremity (LE) musculoskeletal injury (MSKI) in U.S. Army trainees. Gait mechanics, including early stance vertical ground reaction forces (GRFs) and peak tibial accelerations (TA), have been associated with overuse LE MSKIs in non-military populations. However, these associations have not been explored in military trainees. PURPOSE: To investigate preliminary associations of gait mechanics with overuse LE MSKIs in a limited sample of Army trainees METHODS: Preliminary data from a larger study was available for 120 trainees (77F/43M) out of 916 total. Baseline testing was completed in the first week of Basic Combat Training (BCT). Participants ran (2.68-2.90 m/s) and ruck marched (1.21-1.34 m/s; 18.1 kg pack) on an instrumented treadmill, while GRFs and TAs were collected. Gait variables included: vertical loading rates, stiffness (run only), and peak forces (ruck only), as well as peak vertical and resultant TAs. Participants were followed for MSKI throughout BCT via medical records and grouped as having an overuse LE MSKI. The injury group was compared to an equal number of sex- and age-matched, uninjured controls using independent t-tests or Mann-Whitney U tests. RESULTS: During BCT, 11 trainees sustained an overuse LE MSKI. Means for vertical and resultant TA were 34 and 31% higher respectively in the injured group during running, however these, and other differences, were not significant (see Table). CONCLUSION: These preliminary results suggest that GRFs and TAs during gait are not higher in individuals with overuse LE MSKIs. However, more robust analyses with a complete sample are needed to establish whether there is an association between these variables and injury. Supported by US DoD award W81XWH-20-C-0123 P0001. Opinions in this manuscript are the private views of the authors and are not to be construed as official policy or reflecting the views of the US Army. US DoD award W81XWH-20-C-0123 P0001