title: Single leg squat test and its relationship to dynamic knee valgus and injury risk screening.
abstract: BACKGROUND
  Lower extremity injuries are common in athletes. Valid tests to assess for risk of injury that are easily performed during a preparticipation sports physical examination are lacking. Two-dimensional (2D) analysis of the drop-jump test can identify athletes at risk, but it is too expensive and cumbersome to use in this setting.
  
  
  OBJECTIVE
  To identify if those who perform a "positive"(abnormal postures) single leg squat (SLS) test also exhibit greater "dynamic valgus" on the 2D drop-jump test. Our secondary purpose was to assess whether group differences in gender, age, or body mass index are evident between those who exhibit a positive SLS test result versus a negative SLS test result. Also, we wanted to determine any gender differences with the 2D drop-jump test.
  
  
  METHODS
  A cross-sectional study.
  
  
  METHODS
  Private practice, preparticipation sports physical examinations.
  
  
  METHODS
  A total of 142 middle school and high school athletes.
  
  
  METHODS
  Participants performed a SLS test and a drop-jump test during their preparticipation sports physical examination. Individuals were partitioned into groups based on the outcome of their SLS test (positive SLS group versus negative SLS group). Independent sample t-tests were used to evaluate SLS group differences in the drop-jump test, age, and body mass index, and the χ(2) test was used to evaluate SLS group differences in gender (P ≤ .05).
  
  
  METHODS
  The SLS test and drop-jump test.
  
  
  RESULTS
  Seventy-three of the 142 athletes (51%) had a positive SLS test result, whereas 69 athletes (49%) had a negative SLS test result. Individuals in the positive SLS group had a significantly lower knee-hip ratio), indicative of greater dynamic knee valgus, than did those in the negative SLS group (P = .02). Individual characteristics between SLS groups including gender, age, and body mass index were similar.
  
  
  CONCLUSIONS
  The SLS test is a reasonable tool to use in preparticipation sports physical examinations to assess for dynamic knee valgus and the potential risk of lower extremity injury.
authors.affiliation: Orthopedic and Neurosurgical Center of the Cascades, PM&R Division, The Center Foundation, Bend, OR(∗). Electronic address: vugalde@thecenteroregon.com.
authors.forename: Viviane
authors.initials: V
authors.lastname: Ugalde
authors.affiliation: Therapeutic Associates Physical Therapy, Bend, OR(†).
authors.forename: Chuck
authors.initials: C
authors.lastname: Brockman
authors.affiliation: University of Arizona College of Medicine, Tucson, AZ(‡).
authors.forename: Zach
authors.initials: Z
authors.lastname: Bailowitz
authors.affiliation: Exercise and Sports Science, Oregon State University-Cascades, Bend, OR(§).
authors.forename: Christine D
authors.initials: CD
authors.lastname: Pollard
mesh_terms: D000293:Adolescent; D000367:Age Factors; D001265:Athletic Injuries / Q000209:etiology*; D002648:Child; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D007719:Knee Joint / Q000502:physiology*; D008297:Male; D009043:Motor Activity / Q000502:physiology*; D011187:Posture / Q000502:physiology*; D016059:Range of Motion, Articular / Q000502:physiology*; D015203:Reproducibility of Results; D018570:Risk Assessment; D012737:Sex Factors; D016474:Weight-Bearing / Q000502:physiology