Effect of Concussion on Performance of National Football League Players
in International Journal of Sports Physiology and PerformanceClick name to view affiliation
Purpose:
Lingering neurologic injury after concussion may expose athletes to increased risk if return to play is premature. The authors explored whether on-field performance after concussion is a marker of lingering neurologic injury.
Design:
Retrospective cohort study on 1882 skill-position players who played in the National Football League (NFL) during 2007–2010.
Methods:
Players with concussion based on the weekly injury report were compared with players with other head and neck injuries (controls) on measures of on-field performance using Football Outsiders’ calculation of defense-adjusted yards above replacement (DYAR), a measure of a player’s contribution controlling for game context. Changes in performance, relative to a player’s baseline level of performance, were estimated before and after injury using fixed-effects models.
Results:
The study included 140 concussed players and 57 controls. Players with concussion performed no better or worse than their baseline on return to play. However, a decline in DYAR relative to their prior performance was noted 2 wk and 1 wk before appearing on the injury report. Concussed players performed slightly better than controls in situations where they returned to play the same week as appearing on the injury report.
Conclusions:
On return, concussed NFL players performed at their baseline level of performance, suggesting that players have recovered from concussion. Decline in performance noted 2 wk and 1 wk before appearing on the injury report may suggest that concussion diagnosis was delayed or that concussion can be a multihit phenomenon. Athletic performance may be a novel tool for assessing concussion injury and recovery.
Reams is with the NorthShore Neurological Inst, NorthShore University HealthSystem, Evanston, IL. Hayward is with the Depts of Internal Medicine and of Health Management and Policy, and Burke, the Dept of Neurology, University of Michigan Health System, Ann Arbor, MI. Kutcher is with the Sports Neurology Clinic at the CORE Inst, Brighton, MI.
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