Movement differences persist beyond return to play during walking, jogging and running following sport-related concussion

OBJECTIVES: The objectives of this study were to assess changes in gait using lumbar- and thoracic-mounted inertial measurement units during walking, jogging and running tasks performed on natural grassed surfaces for up to four weeks after return to play post-concussion. DESIGN: This study used a case-control, repeated measures design. METHODS: A total of 16 medically diagnosed sports-related concussions in 15 team sport athletes were included, with one male having two concussions (14 males (89.2 ± 13.9 kg, 21.7 ± 3.3 years) and one female (62.5 kg, 18 years)), alongside healthy age and sex matched controls (15 males (90.4 ± 12.7 kg, 26.2 ± 5 years) and one female (80 kg, 20 years)). Participants completed three × 40-m walk, jog, and run tasks under set- and self-paced conditions across four testing sessions at: return to run, return to play, and 2 and 4-weeks post return to play. Spatiotemporal gait metrics and sample entropy were quantified. Bayesian mixed-effects models were used to assess differences between groups over time. RESULTS: Both sites displayed numerous differences across all gait activities, with positive to very strong evidence to suggest increased mediolateral accelerations (thoracic: BF = 51.29-8000, lumbar: BF = 882.80-8000) and poorer rhythmicity in the vertical axis, measured via sample entropy (thoracic: BF = 9.26-8000, lumbar: BF = 38.22-8000). Most gait metrics improved over time. However, vertical sample entropy displayed little to no improvement for walk and jog activities. CONCLUSIONS: Lumbar- and thoracic-mounted inertial measurement units show differences in gait post-concussion which varies depending on movement velocity.