Baseline postural control and lower extremity injury incidence among those with a history of concussion

Context: Lower extremity musculoskeletal (LEMSK) injury may be more prevalent among those with a history of sport-related concussion (SRC). Objective: To investigate the relationship between baseline postural control metrics and the LEMSK injury incidence in National Collegiate Athletic Association Division I student-athletes with a history of SRC. Setting: National Collegiate Athletic Association Division I athletes. Design: Cohort study. Patients or Other Participants: Of 84 total athletes (62 males), 42 had been previously diagnosed with an SRC, and 42 were matched controls based on age, sex, height, weight, and sport. Main Outcome Measure(s): During the preseason baseline evaluation, all participants performed 3 trials of eyes-open and eyes-closed upright quiet stance on a force platform. Medical charts were assessed for all the LEMSK injuries that occurred from preseason baseline to 1 year later. Center-of-pressure data in the anteroposterior and mediolateral directions were filtered before we calculated root mean square and mean excursion velocity; the complexity index was calculated from the unfiltered data. Factorial analysis-of-variance models were used to examine differences between groups and across conditions for root mean square; mean excursion velocity, complexity index, and tests of association to examine between-groups LEMSK differences; and logistic regression models to predict LEMSK. Results: Concussion history and injury incidence were related in the SRC group (P ¼ .043). The complexity index of the SRC group was lower with eyes closed (14.08 6 0.63 versus 15.93 6 0.52) and eyes open (10.25 6 0.52 vs 11.80 6 0.57) in the mediolateral direction than for the control participants (P, .05). Eyes-open root mean square in the mediolateral direction was greater for the SRC group (5.00 6 0.28 mm) than the control group (4.10 6 0.22 mm). Logistic regression models significantly predicted LEMSK only in control participants. Conclusions: These findings may suggest that LEMSK after SRC cannot be predicted from postural-control metrics at baseline.