title: Prevalence of freestyle biomechanical errors in elite competitive swimmers.
abstract: BACKGROUND
  Poor freestyle stroke biomechanics is a suggested risk factor for shoulder pain and pathology, but this has not been proven in biomechanical or clinical studies. Furthermore, the prevalence of these theoretical errors has not been identified, which would help coaches, athletic trainers, and researchers determine the most appropriate errors to focus on and develop interventions.
  
  
  OBJECTIVE
  The majority of swimmers will present with at least 1 freestyle stroke error.
  
  
  METHODS
  Cross-sectional study.
  
  
  METHODS
  Level 4.
  
  
  METHODS
  Stroke biomechanics for 31 swimmers from a collegiate swimming team were captured using underwater/above-water cameras. Each video was evaluated for biomechanical errors: a dropped elbow during the pull-through phase, a dropped elbow during the recovery phase, an eyes-forward head-carrying angle, incorrect hand position during hand entry, incorrect hand entry angle, incorrect pull-through pattern, and inadequate body roll. Error prevalence was calculated, and relationships among the errors were evaluated using chi-square statistics.
  
  
  RESULTS
  A dropped elbow during the pull-through phase (61.3%) and a dropped elbow during the recovery phase (53.2%) had the highest prevalence. A dropped elbow during the recovery phase was significantly associated with a thumb-first hand entry angle (P = 0.027) and incorrect hand entry position (P = 0.009). An eyes-forward head-carrying angle was associated with an incorrect pull-through pattern (P = 0.047).
  
  
  CONCLUSIONS
  Biomechanical errors potentially detrimental to the shoulder are prevalent among swimmers. Many of the errors were interrelated, suggesting that one error may lead to other errors.
  
  
  CONCLUSIONS
  These errors highlight the need for proper stroke instruction and evaluation to decrease the risk of shoulder injury in competitive swimmers.
authors.affiliation: Department of Physical Therapy, School of Health and Rehabilitation Sciences, University of Pittsburgh, Pittsburgh, Pennsylvania.
authors.forename: Bonnie
authors.initials: B
authors.lastname: Virag
authors.affiliation: Human Movement Science Curriculum, Sports Medicine Research Laboratory, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina.
authors.forename: Elizabeth E
authors.initials: EE
authors.lastname: Hibberd
authors.affiliation: Department of Health and Kinesiology, University of Texas at San Antonio, San Antonio, Texas.
authors.forename: Sakiko
authors.initials: S
authors.lastname: Oyama
authors.affiliation: Department of Exercise and Sport Science, Sports Medicine Research Laboratory, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina.
authors.forename: Darin A
authors.initials: DA
authors.lastname: Padua
authors.affiliation: Department of Exercise and Sport Science, Sports Medicine Research Laboratory, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina.
authors.forename: Joseph B
authors.initials: JB
authors.lastname: Myers
keywords: biomechanics; injury prevention; shoulder injury; swimming