@article{ref1,
title="Effect of concussion on performance of National Football League Players",
journal="International journal of sports physiology and performance",
year="2017",
author="Reams, Nicole and Hayward, Rodney A. and Kutcher, Jeffrey S. and Burke, James F.",
volume="12",
number="8",
pages="1100-1104",
abstract="PURPOSE: Lingering neurologic injury after concussion may expose athletes to increased risk if return-to-play is premature. We explored whether on-field performance after concussion is a marker of lingering neurologic injury. <br><br>METHODS: Retrospective cohort study on 1,882 skill-position players who played in the National Football League (NFL) during 2007-2010. Players with concussion based on the weekly injury report, were compared to 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. <br><br>RESULTS: The study included 140 concussed players and 57 controls. Players with concussion performed no better or worse than their baseline upon return-to-play. However, a decline in DYAR, relative to their prior performance, was noted two weeks and one week prior to 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. <br><br>CONCLUSIONS: Upon return, concussed NFL players performed at their baseline level of performance, suggesting that players have recovered from concussion. Decline in performance noted 2 weeks and 1 week prior to appearing on the injury report may suggest that concussion diagnosis was delayed or that concussion can be a multi-hit phenomenon. Athletic performance may be a novel tool for assessing concussion injury and recovery.  keywords American football<p /> <p>Language: en</p>",
language="en",
issn="1555-0265",
doi="10.1123/ijspp.2016-0508",
url="http://dx.doi.org/10.1123/ijspp.2016-0508"
}