title: Style of Play and Rate of Concussions in the National Football League.
abstract: BACKGROUND
  The majority of studies on concussion in the National Football League (NFL) focus on testing, evaluation, and outcomes. Meanwhile, there is a paucity of research on how a team's style of play influences the risk of concussion.
  
  
  OBJECTIVE
  Style of play, such as offensive and defensive strategies, is associated with the rate of concussions in the NFL.
  
  
  METHODS
  Descriptive epidemiology study.
  
  
  METHODS
  The current study retrospectively analyzed data from the 2012 to 2014 NFL regular seasons. Reported numbers of concussions were stratified by each team and each position and were compared based on style of play, including offensive scheme (West Coast offense, Air Coryell offense, or other offensive schemes) and defensive alignment (3-4 or 4-3), attempts statistics, per-drive statistics, and offensive and defensive productions, along with strength of schedule (SoS) and team quality measured by simple rating system (SRS). Data analyses included descriptive statistics, 1-way analysis of variance, correlation analysis, and regression analysis.
  
  
  RESULTS
  There were 437 documented concussions during the 2012 to 2014 NFL regular seasons, with a mean 4.6 concussions per season per team. In general, players most involved in pass plays reported more concussions. The number of concussions sustained by offensive players was significantly higher among the teams adopting the West Coast offense (mean, 3.0) than among those utilizing the Air Coryell offense (mean, 1.6; P = .006) or those with non-West Coast offenses combined (mean, 1.9; P = .004). The multiple regression analysis revealed that the West Coast offense or not, SoS, and SRS explained 25.3% of the variance in the number of concussions by offensive players. After accounting for SRS, the West Coast offense was found to be a significant predictor of the number of concussions (P = .007), while there was a tendency for SoS to be inversely associated with the number of concussions (P = .105). None of the variables for attempts statistics, per-drive statistics, and offensive production were significantly associated with the number of concussions in the regression analysis.
  
  
  CONCLUSIONS
  In the NFL, players most involved in pass plays appear to be at increased risk for concussions. The West Coast offense may be associated with a greater risk of concussion. Furthermore, teams with easier schedules may have more players sustaining concussions.
authors.affiliation: Division of Physical Medicine & Rehabilitation, University of Utah, Salt Lake City, Utah, USA.
authors.forename: Masaru
authors.initials: M
authors.lastname: Teramoto
authors.affiliation: Department of Orthopaedic Surgery, University of Utah, Salt Lake City, Utah, USA.
authors.forename: David J
authors.initials: DJ
authors.lastname: Petron
authors.affiliation: Department of Physical & Life Sciences, Nevada State College, Henderson, Nevada, USA.
authors.forename: Chad L
authors.initials: CL
authors.lastname: Cross
authors.affiliation: Division of Physical Medicine & Rehabilitation, University of Utah, Salt Lake City, Utah, USA.
authors.forename: Stuart E
authors.initials: SE
authors.lastname: Willick
keywords: National Football League (NFL); West Coast offense; concussion; epidemiology; risk factor; statistics; style of play