title: Association Between Anatomical Characteristics, Knee Laxity, Muscle Strength, and Peak Knee Valgus During Vertical Drop-Jump Landings.
abstract: METHODS
  Controlled laboratory study; cross-sectional.
  
  
  OBJECTIVE
  To investigate the relationship among anatomical variables, knee laxity, muscle strength, and peak knee valgus angles during a vertical drop-jump landing task.
  
  
  BACKGROUND
  Excessive knee valgus has been associated with anterior cruciate ligament injury in females; however, the influence of anatomical characteristics, knee laxity, and muscle strength on frontal plane knee motion is not completely understood.
  
  
  METHODS
  Norwegian elite female soccer players (n = 279; mean ± SD age, 21 ± 4 years; height, 167 ± 6 cm; body mass, 63 ± 7 kg) were evaluated from 2009 through 2012. The evaluation included 3-D motion analysis of a vertical drop jump, anatomical measures (height, static knee valgus, leg length, and static foot posture), knee laxity, and muscle strength (quadriceps, hamstrings, and hip abductors). Multiple linear regression analyses were used to investigate the relationships among anatomical characteristics, knee laxity, muscle strength, and peak knee valgus angles.
  
  
  RESULTS
  Anatomical characteristics explained 11% of the variance in peak knee valgus angles (P<.001), with height and static knee valgus being significant predictors.
  
  
  CONCLUSIONS
  Greater body height and static knee valgus were associated with greater peak knee valgus angles during a vertical drop-jump landing task. However, these variables only explained 11% of the variance in peak knee valgus.
authors.forename: Agnethe
authors.initials: A
authors.lastname: Nilstad
authors.forename: Tron
authors.initials: T
authors.lastname: Krosshaug
authors.forename: Kam-Ming
authors.initials: KM
authors.lastname: Mok
authors.forename: Roald
authors.initials: R
authors.lastname: Bahr
authors.forename: Thor Einar
authors.initials: TE
authors.lastname: Andersen
mesh_terms: D000293:Adolescent; D000070598:Anterior Cruciate Ligament Injuries; D001696:Biomechanical Phenomena; D001827:Body Height; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D007593:Joint Instability / Q000503:physiopathology; D007718:Knee Injuries / Q000503:physiopathology; D007719:Knee Joint / Q000033:anatomy & histology* / Q000502:physiology*; D053580:Muscle Strength / Q000502:physiology*; D059385:Plyometric Exercise; D012307:Risk Factors; D055815:Young Adult
keywords: anterior cruciate ligament; biomechanics; female; football; screening; soccer