Change in Head Impact Exposure following Return to Play in Concussed Football Athletes

Abstract Background Following sport-related concussion, early head impact exposure and premature return to play is known to increase risk of repeat concussion in football athletes, yet athletes’ true post-injury head impact exposure profiles and biomechanical progression have not been explored. Accordingly, this study explored how American college football athletes alter playing style during their return from concussion, particularly within the same athletic season. Methods Using head impact exposure profiles of fifty-two collegiate football athletes from six NCAA Division I programs, this analysis compared daily volume of head impacts following concussion with pre-injury levels and further compared these athletes to team- and position-matched controls to minimize season- or team-related factors. Additionally, this study provided an analysis of the possible association between length of recovery time and change in head impact exposure following concussion using continuous linear regression. Results Over 40% of concussed athletes did not reach their pre-injury level of head impact exposure at any point during the remainder of the season segment that the concussion occurred. Furthermore, concussed athletes showed significantly larger decreases than non-concussed athletes over the same time period. Finally, longer recovery times after concussion were associated with larger decreases in head impact exposure over the remaining contact days within the season segment. Conclusions This study provide evidence for a shift in playing style after returning from concussion, both in the immediate days after return to play as well as over extended periods of time within the season. These findings will help to better inform the management of athletes returning from concussion.