title: Real-time head acceleration measurement in girls' youth soccer.
abstract: OBJECTIVE
  The purpose of the current study was to collect real-time head acceleration data for soccer impacts during girls' youth (U14) soccer play.
  
  
  METHODS
  Linear and angular head accelerations were collected during girls' youth soccer scrimmages using a wireless head acceleration measurement device (the Head Impact Telemetry System). After field data collection, each individual impact was analyzed. The type of impact, header or nonheader, was determined, and nonheader impacts were further assessed by the category of impact. The head injury criterion and resultant linear and angular accelerations were analyzed and compared with current injury tolerance values for all impacts.
  
  
  RESULTS
  A total of 47 header and 20 nonheader impacts were observed during the study. The front of the head experienced more headers than the other locations (n = 17). Header impacts ranged in peak linear acceleration from 4.5 g to 62.9 g and in peak angular head acceleration from 444.8 to 8869.1 rad·s(-2). The majority of the nonheader impacts (40%) were player collisions with other players. Only one goalpost collision occurred, but it resulted in the highest peak angular acceleration (5179.5 rad·s(-2)) and was the only nonheader impact to exceed any of the tolerance levels.
  
  
  CONCLUSIONS
  Head accelerations were found to exceed the majority of previous laboratory studies. None of the impacts exceeded linear acceleration tolerance values for concussion, but angular accelerations did exceed the suggested limits. Three angular acceleration measurements for heading events (4509.8, 5298.3, and 8869.1 rad·s(-2)) exceeded the concussion tolerance values, but no concussions were diagnosed during the study.
authors.affiliation: Department of Biomedical Engineering, College of Engineering, Wayne State University, Detroit, MI 48201, USA. cbir@wayne.edu
authors.forename: Erin M
authors.initials: EM
authors.lastname: Hanlon
authors.forename: Cynthia A
authors.initials: CA
authors.lastname: Bir
mesh_terms: D000054:Acceleration; D000293:Adolescent; D000704:Analysis of Variance; D006259:Craniocerebral Trauma / Q000175:diagnosis*; D005260:Female; D019416:Head Movements; D006801:Humans; D012916:Soccer / Q000293:injuries*; D013686:Telemetry / Q000295:instrumentation; D014743:Videotape Recording