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Brief Report
February 1, 2021

Opportunities for Prevention of Concussion and Repetitive Head Impact Exposure in College Football Players: A Concussion Assessment, Research, and Education (CARE) Consortium Study

Author Affiliations
  • 1Department of Neurosurgery, Medical College of Wisconsin, Milwaukee
  • 2Department of Biomedical Engineering, Virginia Tech, Blacksburg
  • 3School of Public Health-Bloomington, Department of Epidemiology and Biostatistics, Indiana University, Bloomington
  • 4Department of Psychiatry, Indiana University School of Medicine, Indianapolis
  • 5Michigan Concussion Center, University of Michigan, Ann Arbor
  • 6UCLA Steve Tisch BrainSPORT Program, Department of Neurosurgery, University of California at Los Angeles
  • 7UCLA Steve Tisch BrainSPORT Program, Department of Pediatrics, University of California at Los Angeles
  • 8Department of Family Medicine and Orthopedic Surgery, University of California at Los Angeles
  • 9John A. Feagin Jr Sports Medicine Fellowship, Keller Army Hospital Military Academy, West Point, New York
  • 10Department of Physical Medicine and Rehabilitation, Uniformed Services University, Bethesda, Maryland
  • 11Air Force Academy, Colorado
  • 12Matthew Gfeller Sport-Related Traumatic Brain Injury Research Center, Department of Exercise and Sport Science, University of North Carolina at Chapel Hill
  • 13Department of Orthopedics and Rehabilitation, School of Medicine and Public Health, University of Wisconsin, Madison
  • 14Department of Biomedical Engineering, Medical College of Wisconsin, Milwaukee
JAMA Neurol. 2021;78(3):346-350. doi:10.1001/jamaneurol.2020.5193
Key Points

Question  Where might there be opportunities to do the greatest good toward reducing overall concussion incidence and head impact exposure (HIE) in collegiate football?

Findings  In this cohort study, concussion incidence and HIE were disproportionately higher in the preseason than the regular season, and most concussions and HIE occurred during football practices.

Meaning  These findings point to specific areas where public policy, education, and other prevention strategies could be targeted to make the greatest overall reduction in concussion incidence and HIE in college football, which has important implications for protecting the safety and health of collegiate football players.


Importance  Concussion ranks among the most common injuries in football. Beyond the risks of concussion are growing concerns that repetitive head impact exposure (HIE) may increase risk for long-term neurologic health problems in football players.

Objective  To investigate the pattern of concussion incidence and HIE across the football season in collegiate football players.

Design, Setting, and Participants  In this observational cohort study conducted from 2015 to 2019 across 6 Division I National Collegiate Athletic Association (NCAA) football programs participating in the Concussion Assessment, Research, and Education (CARE) Consortium, a total of 658 collegiate football players were instrumented with the Head Impact Telemetry (HIT) System (46.5% of 1416 eligible football players enrolled in the CARE Advanced Research Core). Players were prioritized for instrumentation with the HIT System based on their level of participation (ie, starters prioritized over reserves).

Exposure  Participation in collegiate football games and practices from 2015 to 2019.

Main Outcomes and Measures  Incidence of diagnosed concussion and HIE from the HIT System.

Results  Across 5 seasons, 528 684 head impacts recorded from 658 players (all male, mean age [SD], 19.02 [1.25] years) instrumented with the HIT System during football practices or games met quality standards for analysis. Players sustained a median of 415 (interquartile range [IQR], 190-727) recorded head impacts (ie, impacts) per season. Sixty-eight players sustained a diagnosed concussion. In total, 48.5% of concussions (n = 33) occurred during preseason training, despite preseason representing only 20.8% of the football season (0.059 preseason vs 0.016 regular-season concussions per team per day; mean difference, 0.042; 95% CI, 0.020-0.060; P = .001). Total HIE in the preseason occurred at twice the proportion of the regular season (324.9 vs 162.4 impacts per team per day; mean difference, 162.6; 95% CI, 110.9-214.3; P < .001). Every season, HIE per athlete was highest in August (preseason) (median, 146.0 impacts; IQR, 63.0-247.8) and lowest in November (median, 80.0 impacts; IQR, 35.0-148.0). Over 5 seasons, 72% of concussions (n = 49) (game proportion, 0.28; 95% CI, 0.18-0.40; P < .001) and 66.9% of HIE (262.4 practices vs 137.2 games impacts per player; mean difference, 125.3; 95% CI, 110.0-140.6; P < .001) occurred in practice. Even within the regular season, total HIE in practices (median, 175.0 impacts per player per season; IQR, 76.0-340.5) was 84.2% higher than in games (median, 95.0 impacts per player per season; IQR, 32.0-206.0).

Conclusions and Relevance  Concussion incidence and HIE among college football players are disproportionately higher in the preseason than regular season, and most concussions and HIE occur during football practices, not games. These data point to a powerful opportunity for policy, education, and other prevention strategies to make the greatest overall reduction in concussion incidence and HIE in college football, particularly during preseason training and football practices throughout the season, without major modification to game play. Strategies to prevent concussion and HIE have important implications to protecting the safety and health of football players at all competitive levels.

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    2 Comments for this article
    Football Concussions
    Charles Brill, MD | Thomas Jefferson Uiverson
    Consider putting portable EEG monitoring devices on players and see how often brain voltage falls after contact.
    Misinterpretation by the public
    Jerome Enad, MD, FAAOS, FAANA | Uniformed Services University of the Health Sciences
    I came by this article via a sports fan forum linking to the New York Times review of the actual JAMA Neurology article. The points that the NYT and sports fans seemed to be focused on are that more HIE and concussions occurred in practices vs regular season, leading them to incorrectly conclude that practices are more risky than games - despite the fact that the article states that they did "not collect epidemiologic data to allow calculation of injury rates per athlete exposures."
    Ostensibly, there are many more practices in a season than games, so any type of injury
    (not just concussions) are going to occur more times during practice. Even though their data showed that there were more HIE and concussions overall during practice than during games, their data also showed that the average player sustains more HIE during a game vs practice.
    Therefore, in order to compare the relative risk of high impact hits (or concussions) in practice vs games, one would need to measure injury risk (# of injuries / exposure), within each setting.