Effect of subconcussive impacts on functional outcomes over a single collegiate football season

Context In collision sports, particularly American football, athletes can accumulate thousands of subconcussive impacts, or head acceleration events (HAEs), across a single season; however, the short-term consequences of these impacts are not well understood. Objective To investigate the effects of the accumulation of impacts during practices on cognitive functions over a single football season. Design Prospective observational study. Setting Athletic training room and University laboratory. Participants Twenty-three NCAA Football Bowl Subdivision players. Main outcome measures Helmet accelerometers during practices and virtual reality testing (VR; balance, reaction time, spatial memory) before and after the season. Results Preseason had the majority of ≥80 G impacts while during the season had the majority of ≥25 G to <80 G impacts and positional differences showed that linemen had the majority of both types. Virtual reality analysis revealed that scores significantly decreased after the season for spatial navigation (p < 0.05) but not for balance or reaction time. Significant correlations (p < 0.05) were found between cognitive measures and player demographic variables. Conclusions Even in the absence of clinical symptoms and concussion diagnosis, repetitive impacts may cause cognitive alterations. Documenting the distribution of impact quantity and intensity as a function of time and position may be considered by coaches and clinicians to reduce the accumulation of impacts in athletes exposed in contact sports.