Repetitive head impacts do not affect postural control following a competitive athletic season

Evidence suggests that Repetitive Head Impacts (RHI) directly influence the brain over the course of a single contact collision season yet do not significantly impact a player's performance on the standard clinical concussion assessment battery. The purpose of this study was to investigate changes in static postural control after a season of RHI in Division I football athletes using more sensitive measures of postural control as compared to a non-head contact sports. Fourteen Division I football players (CON) (age = 20.4 ± 1.12 years) and fourteen non-contact athletes (NON) (2 male, 11 female; age = 19.85 ± 1.21 years) completed a single trial of two minutes of eyes open quiet upright stance on a force platform (1000 Hz) prior to athletic participation (PRE) and at the end of the athletic season (POST). All CON athletes wore helmets outfitted with Head Impact Telemetry (HIT) sensors and total number of RHI and linear accelerations forces of each RHI were recorded. Center of pressure root mean square (RMS), peak excursion velocity (PEV), and sample entropy (SampEn) in the anteroposterior (AP) and mediolateral (ML) directions were calculated. CON group experienced 649.5 ± 496.8 mean number of impacts, 27.1 ± 3.0 mean linear accelerations, with ≈ 1% of total player impacts exceeded 98 g over the course of the season. There were no significant interactions for group x time RMS in the AP (p = 0.434) and ML (p = 0.114) directions, PEV in the AP (p = 0.262) and ML (p = 0.977) directions, and SampEn in the AP (p = 0.499) and ML (p = 0.984) directions. In addition, no significant interactions for group were observed for RMS in the AP (p = 0.105) and ML (p = 0.272) directions, PEV in the AP (p = 0.081) and ML (p = 0.143) directions, and SampEn in the AP (p = 0.583) and ML (p = 0.129) directions. These results suggest that over the course of a single competitive season, RHI do not negatively impact postural control even when measured with sensitive non-linear metrics.