Reaction Time and Joint Kinematics During Functional Movement in Recently Concussed Individuals.

ABSTRACT

OBJECTIVE: To compare movement reaction time and joint kinematics between athletes with recent concussion and matched control recreational athletes during 3 functional tasks. DESIGN: Cross-sectional. SETTING: Laboratory. PARTICIPANTS: College-aged recreational athletes (N=30) comprising 2 groups (15 participants each) (1) recent concussion group (median time since concussion, 126d; range, 28-432d) and (2) age- and sex-matched control group with no recent concussions. INTERVENTIONS: We investigated movement reaction time and joint kinematics during 3 tasks (1) jump landing, (2) anticipated cut, and (3) unanticipated cut. MAIN OUTCOME MEASURES: Reaction time and reaction time cost (jump landing reaction time-cut reaction time/jump landing reaction time×100%), along with trunk, hip, and knee joint angles in the sagittal and frontal planes at initial ground contact. RESULTS: There were no reaction time between-group differences, but the control group displayed improved reaction time cost (10.7%) during anticipated cutting compared with the concussed group (0.8%; P=.030). The control group displayed less trunk flexion than the concussed group during the nondominant anticipated cut (5.1° difference; P=.022). There were no other kinematic between-group differences (P≥.079). CONCLUSIONS: We observed subtle reaction time and kinematic differences between individuals with recent concussion and those without concussion more than a month after return to activity after concussion. The clinical interpretation of these findings remains unclear, but may have future implications for postconcussion management and rehabilitation.