title: Prevalence of Sport Specialization in High School Athletics: A 1-Year Observational Study.
abstract: The prevalence of sport specialization in high school athletes is unknown. This information is needed to determine the scope of this issue in an active population.
  
  
  
  To determine the prevalence of sport specialization in high school athletes and to determine if specialization is influenced by classification method, year in school, sex, and school size. A secondary purpose was to determine if highly specialized athletes would be more likely to report a history of lower extremity injuries.
  
  
  
  Cross-sectional study; Level of evidence, 3.
  
  
  
  High school athletes between the ages of 13 and 18 years from 2 local high schools completed both a sport specialization survey and an injury history survey. Athletes were classified into low, moderate, or high specialization groups using a recently developed 3-point system and were also classified using a self-classification method.
  
  
  
  A total of 302 athletes completed the surveys and were classified as low specialization (n = 105, 34.8%), moderate specialization (n = 87, 28.8%), or high specialization (n = 110, 36.4%). Athletes from the small school were more likely to be classified in the low specialization group (low, 43%; moderate, 32%; high, 25%) compared with those from the large school (low, 26%; moderate, 26%; high, 48%) (P < .001). Athletes in the high specialization group were more likely to report a history of overuse knee injuries (n = 18) compared with moderate (n = 8) or low specialization (n = 7) athletes (P = .048). Athletes who trained in one sport for more than 8 months out of the year were more likely to report a history of knee injuries (odds ratio [OR], 2.32; 95% CI, 1.22-4.44; P = .009), overuse knee injuries (OR, 2.93; 95% CI, 1.16-7.36; P = .018), and hip injuries (OR, 2.74; 95% CI, 1.09-6.86; P = .026). Using the self-classification method, more participants self-classified as multisport (n = 213, 70.5%) than single sport (n = 89, 29.5%). Athletes from the small school were more likely to classify themselves as multisport (n = 128, 86%) (P < .001) than those from the large school (n = 85, 56%). There were no differences in the history of hip, knee, or ankle injuries between athletes who self-classified as single sport (hip: n = 10, 3%; knee: n = 19, 6%; ankle: n = 35, 12%) versus those who self-classified as multisport (hip: n = 45, 8%; knee: n = 23, 15%; ankle: n = 98, 33%) (P > .370).
  
  
  
  Classification method and school size influenced the prevalence of specialization in high school athletes. Highly specialized athletes were more likely to report a history of overuse knee or hip injuries. Participating in a single sport for more than 8 months per year appeared to be an important factor in the increased injury risk observed in highly specialized athletes.
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 drbell2@wisc.edu.
authors.forename: David R
authors.initials: DR
authors.lastname: Bell
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: 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
mesh_terms: D000293:Adolescent; D016512:Ankle Injuries / Q000453:epidemiology; D001265:Athletic Injuries / Q000453:epidemiology*; D003430:Cross-Sectional Studies; D005260:Female; D025981:Hip Injuries / Q000453:epidemiology; D006801:Humans; D007718:Knee Injuries / Q000453:epidemiology; D035002:Lower Extremity / Q000293:injuries*; D008297:Male; D015995:Prevalence; D012574:Schools; D013038:Specialization / Q000706:statistics & numerical data*; D013177:Sports / Q000706:statistics & numerical data*; D014922:Wisconsin / Q000453:epidemiology
keywords: adolescent; overuse injury; specialization; youth athlete