Single-Leg Hop Stabilization Biomechanics Throughout Concussion Recovery: A Prospective Cohort Study

Abstract

Heightened musculoskeletal injury risk after concussion likely relates to human movement, but post-concussion biomechanics have not been explored early after injury. PURPOSE: To compare single leg hop stabilization biomechanics under single and dual task conditions between concussed and healthy controls acutely (≤7 days) and when asymptomatic (≤72 hours of symptom resolution). METHODS: Ten concussed and 10 matched controls (60% male; 19.4 ± 1.0 yrs; 177.4 ± 13.0 cm; 71.1 ± 17.1 kg) completed a single leg hop stabilization task under single and dual task (subtract by 6’s or 7’s) at both timepoints in a 3D motion capture laboratory (Qualisys-240 Hz; Bertec-1200 Hz). Participants jumped forward from a 30 cm tall box set at 50% of the participant’s height immediately following light stimulus, landed on a single leg (non-dominant), and achieved and held static balance for 10s. We used 2 (group) x 2 (time) mixed-model ANOVAs with Tukey post-hoc tests and Hedges’ g effect sizes to compare single-leg hop stabilization outcomes separately for single and dual task. RESULTS: All results are presented in the Table. Greater concussed single task ankle plantarflexion moments were observed by a group effect (p = 0.048). Slower reaction time was observed acutely among concussed only through an interaction effect (p = 0.026), and both cohorts reacted faster at asymptomatic relative to acute via time effect (p = 0.027). No other statistical differences were present under single task (p ≥ 0.064) or dual task (p ≥ 0.051). CONCLUSION: Slower reaction time and greater ankle moments coupled with potentially meaningful decreased range of motion and increased torque effect sizes trends (Table) suggest stiff, conservative movement acutely after concussion, but not once asymptomatic. Our findings highlight biomechanics outcomes for future research to examine when investigating increased musculoskeletal injury risk post-concussion contributors. Supported by the ACSM Doctoral Grant.