Baseline Postural Control Measures: An Indicator For Increased Injury Frequency Following Sport-related Concussion

Abstract

Recent research indicates that within 1 year following sport-related concussion (SRC), those who have experienced a SRC are 1.97 to 3.5 times more likely to sustain an acute lower extremity (LE) injury with a risk rate that ranges from 2.88 to 6.22 per 1000 athlete exposures. These studies suggest that an association between SRC and LE injury exists, however, no known research has examined the potential cause. It has been suggested that lingering postural control deficits as a result of SRC, may play a role in the increased prevalence of injury. PURPOSE: The purpose of this study was to investigate the potential relationship between baseline postural control metrics and acute LE injury frequency in NCAA Division I athletes with a prior history of SRC. METHODS: Eighty-four NCAA Division I athletes (42 with a history of SRC [CONC]; 42 without a history of SRC [CTRL]) performed three trials of 30 seconds eyes open (EO) and eyes closed (EC) quiet upright stance during pre-participation baseline screening on a force platform (1000Hz). Acute LE injuries were prospectively tracked for a single athletic season following baseline. Raw center of pressure (CoP) data were further analyzed using a custom MATLAB code to obtain Root Mean Square (RMS), Mean Velocity (MEV), and Multiscale Entropy’s Complexity Index (CI) for both anteroposterior (AP) and mediolateral (ML) directions. RESULTS: The results indicated that over the course of the season, 27.4% of the athletes reported an injury (CONC = 15, CTRL = 8 injuries) with a significant association between prior SRC history and incidence of injuries (p=0.043, relative risk=1.88 [CI95 – 1.09, 3.95]). In EO condition, RMS (p=0.049; CONC=5±0.28mm, CRTL=4.1±0.22mm: Cohen’s d=3.6) and CI (p=0.021; CONC=10.25±0.52, CRTL=11.80±0.57: Cohen’s d=2.9) in the ML direction were significantly different between groups. Furthermore, in the EC condition, CI (p=0.026; CONC=14.08±0.63, NORM=15.93±0.52: Cohen’s d=3.2) in the ML directions was significantly different between groups. No other significant differences were observed. CONCLUSION: These results indicate that a prior history of SRC is associated with a greater incidence of LE injury and postural control differences can be detected prior to injury occurrence using postural control variability.