title: The Association of Sport Specialization and Training Volume With Injury History in Youth Athletes.
abstract: BACKGROUND
  Recommendations exist to encourage safe youth participation in sport. These recommendations include not specializing in 1 sport, limiting participation to less than 8 months per year, and limiting participation to fewer hours per week than a child's age. However, limited evidence exists to support or refute these recommendations.
  
  
  OBJECTIVE
  High levels of specialization will be associated with a history of injuries and especially overuse injuries, independent of age, sex, or weekly sport training hours. Athletes who exceed current sport volume recommendations will be more likely to have a history of injuries and overuse injuries.
  
  
  METHODS
  Case-control study; Level of evidence, 3.
  
  
  METHODS
  Youth athletes (n = 2011; 989 female and 1022 male; 12-18 years of age) completed a questionnaire regarding their specialization status, yearly and weekly sport participation volume, and injury history. Specialization was classified as low, moderate, or high using a previously utilized 3-point scale. Athletes were classified into groups based on either meeting or exceeding current volume recommendations (months per year and hours per week). Odds ratios (ORs) and 95% CIs were calculated to investigate associations of specialization and volume of participation with a history of sport-related injuries in the past year ( P ≤ .05).
  
  
  RESULTS
  Highly specialized athletes were more likely to report a previous injury of any kind ( P < .001; OR, 1.59; 95% CI, 1.26-2.02) or an overuse injury ( P = .011; OR, 1.45; 95% CI, 1.07-1.99) in the previous year compared with athletes in the low specialization group. Athletes who played their primary sport more than 8 months of the year were more likely to report an upper extremity overuse injury ( P = .04; OR, 1.68; 95% CI, 1.06-2.80) or a lower extremity overuse injury ( P = .001; OR, 1.66; 95% CI, 1.22-2.30). Athletes who participated in their primary sport for more hours per week than their age (ie, a 16-year-old athlete who participated in his or her primary sport for more than 16 h/wk) were more likely to report an injury of any type ( P = .001; OR, 1.34; 95% CI, 1.12-1.61) in the previous year.
  
  
  CONCLUSIONS
  High levels of specialization were associated with a history of injuries, independent of age, sex, and weekly organized sport volume. Athletes who exceeded volume recommendations were more likely to have a history of overuse injuries.
  
  
  CONCLUSIONS
  Parents and youth athletes should be aware of the risks of specialization and excessive sport volume to maximize safe sport participation.
authors.affiliation: Department of Kinesiology, University of Wisconsin-Madison, Madison, Wisconsin, USA.|Wisconsin Injury in Sport Laboratory, University of Wisconsin-Madison, Madison, Wisconsin, USA.
authors.forename: Eric G
authors.initials: EG
authors.lastname: Post
authors.affiliation: Department of Kinesiology, University of Wisconsin-Madison, Madison, Wisconsin, USA.|Wisconsin Injury in Sport Laboratory, University of Wisconsin-Madison, Madison, Wisconsin, USA.
authors.forename: Stephanie M
authors.initials: SM
authors.lastname: Trigsted
authors.affiliation: Wisconsin Injury in Sport Laboratory, University of Wisconsin-Madison, Madison, Wisconsin, USA.|Department of Orthopedics and Rehabilitation, University of Wisconsin-Madison, Madison, Wisconsin, USA.
authors.forename: Jeremy W
authors.initials: JW
authors.lastname: Riekena
authors.affiliation: Department of Biostatistics and Medical Informatics, University of Wisconsin-Madison, Madison, Wisconsin, USA.
authors.forename: Scott
authors.initials: S
authors.lastname: Hetzel
authors.affiliation: Department of Orthopedics and Rehabilitation, University of Wisconsin-Madison, Madison, Wisconsin, USA.
authors.forename: Timothy A
authors.initials: TA
authors.lastname: McGuine
authors.affiliation: Department of Orthopedics and Rehabilitation, University of Wisconsin-Madison, Madison, Wisconsin, USA.
authors.forename: M Alison
authors.initials: MA
authors.lastname: Brooks
authors.affiliation: Department of Kinesiology, University of Wisconsin-Madison, Madison, Wisconsin, USA.|Wisconsin Injury in Sport Laboratory, University of Wisconsin-Madison, Madison, Wisconsin, USA.|Department of Orthopedics and Rehabilitation, University of Wisconsin-Madison, Madison, Wisconsin, USA.
authors.forename: David R
authors.initials: DR
authors.lastname: Bell
mesh_terms: D000293:Adolescent; D000367:Age Factors; D001265:Athletic Injuries / Q000453:epidemiology*; D016022:Case-Control Studies; D002648:Child; D012090:Cumulative Trauma Disorders / Q000453:epidemiology; D005260:Female; D006801:Humans; D008297:Male; D064797:Physical Conditioning, Human; D012307:Risk Factors; D012737:Sex Factors; D013038:Specialization; D013177:Sports / Q000706:statistics & numerical data*; D013997:Time Factors
keywords: overuse injury; specialization; sport volume; youth sports