title: Impact of Increased Football Field Width on Player High-Speed Collision Rate.
abstract: BACKGROUND
  High-acceleration head impact is a known risk for mild traumatic brain injury (mTBI) based on studies using helmet accelerometry. In football, offensive and defensive players are at higher risk of mTBI due to increased speed of play. Other collision sport studies suggest that increased playing surface size may contribute to reductions in high-speed collisions. We hypothesized that wider football fields lead to a decreased rate of high-speed collisions.
  
  
  METHODS
  Computer football game simulation was developed using MATLAB. Four wide receivers were matched against 7 defensive players. Each offensive player was randomized to one of 5 typical routes on each play. The ball was thrown 3 seconds into play; ball flight time was 2 seconds. Defensive players were delayed 0.5 second before reacting to ball release. A high-speed collision was defined as the receiver converging with a defensive player within 0.5 second of catching the ball. The simulation counted high-speed collisions for 1 team/season (65 plays/game for 16 games/season = 1040 plays/season) averaged during 10 seasons, and was validated against existing data using standard field width (53.3 yards). Field width was increased in 1-yard intervals up to 58.3 yards.
  
  
  RESULTS
  Using standard field width, 188 ± 4 high-speed collisions were seen per team per season (18% of plays). When field width increased by 3 yards, high-speed collision rate decreased to 135 ± 3 per team per season (28% decrease; P < 0.0001).
  
  
  CONCLUSIONS
  Even small increases in football field width can lead to substantial decline in high-speed collisions, with potential for reducing instances of mTBI in football players.
authors.affiliation: Department of Neurosurgery, University of Michigan, Ann Arbor, Michigan, USA.
authors.forename: Jacob R
authors.initials: JR
authors.lastname: Joseph
authors.affiliation: Department of Neurosurgery, University of Michigan, Ann Arbor, Michigan, USA.
authors.forename: Siri S
authors.initials: SS
authors.lastname: Khalsa
authors.affiliation: Department of Neurosurgery, University of Michigan, Ann Arbor, Michigan, USA.
authors.forename: Brandon W
authors.initials: BW
authors.lastname: Smith
authors.affiliation: Department of Neurosurgery, University of Michigan, Ann Arbor, Michigan, USA. Electronic address: ppark@med.umich.edu.
authors.forename: Paul
authors.initials: P
authors.lastname: Park
mesh_terms: D061725:Accelerometry; D001696:Biomechanical Phenomena; D001924:Brain Concussion / Q000453:epidemiology*; D003198:Computer Simulation; D005538:Football / Q000293:injuries*; D006260:Head Protective Devices; D006801:Humans
keywords: Computer simulation; Concussion; Football field; Mild traumatic brain injury