title: Field-based measures of head impacts in high school football athletes.
abstract: OBJECTIVE
  Recent technological advances have allowed the in-vivo measurement of impacts sustained to the head during helmeted sports. These measurements are of interest to researchers and clinicians for their potential to understand both the underlying mechanics of concussive injuries and the potential for real-time injury diagnostics. Following an overview of impact biomechanics, this review will evaluate the following: in-vivo technology being used in American football players; impact frequencies and magnitudes; and the biomechanical threshold for concussion.
  
  
  RESULTS
  The average high school athlete sustains over 650 impacts in a season, and the level at which concussion occurs is approximately 100  g and 5500  rad/s/s.
  
  
  CONCLUSIONS
  High school athletes sustain a significant number of head impacts each year. The impacts are similar in both volume and magnitude when compared with collegiate athletes. The magnitude of impact that results in concussion is also the same at both levels of play, although the collegiate athlete may have a higher injury tolerance.
authors.affiliation: Neurotrauma Research Laboratory, University of Michigan, Michigan NeuroSport, Michigan, USA. broglio@umich.edu
authors.forename: Steven P
authors.initials: SP
authors.lastname: Broglio
authors.forename: James T
authors.initials: JT
authors.lastname: Eckner
authors.forename: Jeffery S
authors.initials: JS
authors.lastname: Kutcher
mesh_terms: D000293:Adolescent; D056352:Athletes; D001696:Biomechanical Phenomena; D001924:Brain Concussion / Q000175:diagnosis*; D005538:Football / Q000293:injuries*; D006801:Humans; D013334:Students; D014481:United States