title: Sex Differences in Anthropometrics and Heading Kinematics Among Division I Soccer Athletes.
abstract: BACKGROUND
  Soccer players head the ball repetitively throughout their careers; this is also a potential mechanism for a concussion. Although not all soccer headers result in a concussion, these subconcussive impacts may impart acceleration, deceleration, and rotational forces on the brain, leaving structural and functional deficits. Stronger neck musculature may reduce head-neck segment kinematics.
  
  
  OBJECTIVE
  The relationship between anthropometrics and soccer heading kinematics will not differ between sexes. The relationship between anthropometrics and soccer heading kinematics will not differ between ball speeds.
  
  
  METHODS
  Pilot, cross-sectional design.
  
  
  METHODS
  Level 3.
  
  
  METHODS
  Division I soccer athletes (5 male, 8 female) were assessed for head-neck anthropometric and neck strength measurements in 6 directions (ie, flexion, extension, right and left lateral flexions and rotations). Participants headed the ball 10 times (25 or 40 mph) while wearing an accelerometer secured to their head. Kinematic measurements (ie, linear acceleration and rotational velocity) were recorded at 2 ball speeds.
  
  
  RESULTS
  Sex differences were observed in neck girth ( t = 5.09, P < 0.001), flexor and left lateral flexor strength ( t = 3.006, P = 0.012 and t = 4.182, P = 0.002, respectively), and rotational velocity at both speeds ( t = -2.628, P = 0.024 and t = -2.227, P = 0.048). Neck girth had negative correlations with both linear acceleration ( r = -0.599, P = 0.031) and rotational velocity at both speeds ( r = -0.551, P = 0.012 and r = -0.652, P = 0.016). Also, stronger muscle groups had lower linear accelerations at both speeds ( P < 0.05).
  
  
  CONCLUSIONS
  There was a significant relationship between anthropometrics and soccer heading kinematics for sex and ball speeds.
  
  
  CONCLUSIONS
  Neck girth and neck strength are factors that may limit head impact kinematics.
authors.affiliation: Department of Kinesiology, Michigan State University, East Lansing, Michigan.
authors.forename: Abigail C
authors.initials: AC
authors.lastname: Bretzin
authors.affiliation: Department of Kinesiology, Temple University, Philadelphia, Pennsylvania.
authors.forename: Jamie L
authors.initials: JL
authors.lastname: Mansell
authors.affiliation: Department of Kinesiology, Temple University, Philadelphia, Pennsylvania.
authors.forename: Ryan T
authors.initials: RT
authors.lastname: Tierney
authors.affiliation: Department of Athletic Training, East Stroudsburg University, East Stroudsburg, Pennsylvania.
authors.forename: Jane K
authors.initials: JK
authors.lastname: McDevitt
mesh_terms: D000886:Anthropometry; D001696:Biomechanical Phenomena; D001924:Brain Concussion / Q000503:physiopathology / Q000517:prevention & control; D003430:Cross-Sectional Studies; D005260:Female; D006257:Head / Q000502:physiology*; D006801:Humans; D008297:Male; D053580:Muscle Strength / Q000502:physiology*; D009333:Neck / Q000033:anatomy & histology* / Q000502:physiology; D009334:Neck Muscles / Q000502:physiology*; D010865:Pilot Projects; D012737:Sex Factors; D012916:Soccer / Q000293:injuries / Q000502:physiology*
keywords: biomechanics; cervical musculature; head injuries/concussion; neck strength