title: Prediction of Dynamic Postural Stability During Single-Leg Jump Landings by Ankle and Knee Flexibility and Strength.
abstract: Dynamic postural stability is important for injury prevention, but little is known about how lower-extremity musculoskeletal characteristics (range of motion [ROM] and strength) contribute to dynamic postural stability. Knowing which modifiable physical characteristics predict dynamic postural stability can help direct rehabilitation and injury-prevention programs.
  
  
  
  To determine if trunk, hip, knee, and ankle flexibility and strength variables are significant predictors of dynamic postural stability during single-leg jump landings.
  
  
  
  Cross-sectional study.
  
  
  
  Laboratory.
  
  
  
  94 male soldiers (age 28.2 ± 6.2 y, height 176.5 ± 2.6 cm, weight 83.7 ± 26.0 kg).
  
  
  
  None.
  
  
  
  Ankle-dorsiflexion and plantar-flexion ROM were assessed with a goniometer. Trunk, hip, knee, and ankle strength were assessed with an isokinetic dynamometer or handheld dynamometer. The Dynamic Postural Stability Index (DPSI) was used to quantify postural stability. Simple linear and backward stepwise-regression analyses were used to identify which physical characteristic variables were significant predictors of DPSI.
  
  
  
  Simple linear-regression analysis revealed that individually, no variables were significant predictors of the DPSI. Stepwise backward-regression analysis revealed that ankle-dorsiflexion flexibility, ankle-inversion and -eversion strength, and knee-flexion and -extension strength were significant predictors of the DPSI (R2 = .19, P = .0016, adjusted R2 = .15).
  
  
  
  Ankle-dorsiflexion ROM, ankle-inversion and -eversion strength, and knee-flexion and -extension strength were identified as significant predictors of dynamic postural stability, explaining a small amount of the variance in the DPSI.
authors.affiliation: Warrior Human Performance Research Laboratory, University of Pittsburgh, Pittsburgh, PA.
authors.forename: Valerie J
authors.initials: VJ
authors.lastname: Williams
authors.forename: Takashi
authors.initials: T
authors.lastname: Nagai
authors.forename: Timothy C
authors.initials: TC
authors.lastname: Sell
authors.forename: John P
authors.initials: JP
authors.lastname: Abt
authors.forename: Russell S
authors.initials: RS
authors.lastname: Rowe
authors.forename: Mark A
authors.initials: MA
authors.lastname: McGrail
authors.forename: Scott M
authors.initials: SM
authors.lastname: Lephart
mesh_terms: D000328:Adult; D000843:Ankle Joint / Q000502:physiology*; D001696:Biomechanical Phenomena; D003430:Cross-Sectional Studies; D006621:Hip Joint / Q000502:physiology; D006801:Humans; D007719:Knee Joint / Q000502:physiology*; D016014:Linear Models; D008297:Male; D009068:Movement / Q000502:physiology*; D053580:Muscle Strength / Q000502:physiology*; D053581:Muscle Strength Dynamometer; D018482:Muscle, Skeletal / Q000502:physiology*; D004856:Postural Balance / Q000502:physiology*; D016059:Range of Motion, Articular; D013909:Thorax / Q000502:physiology