title: Two- and 3-dimensional knee valgus are reduced after an exercise intervention in young adults with demonstrable valgus during squatting.
abstract: BACKGROUND
  Two-dimensional (or medial knee displacement [MKD]) and 3-dimensional (3D) knee valgus are theorized to contribute to anterior cruciate ligament injuries. However, whether these displacements can be improved in the double-legged squat (DLS) after an exercise intervention is unclear.
  
  
  OBJECTIVE
  To determine if MKD and 3D knee valgus are improved in a DLS after an exercise intervention.
  
  
  METHODS
  Randomized controlled clinical trial.
  
  
  METHODS
  Research laboratory.
  
  
  METHODS
  A total of 32 participants were enrolled in this study and were randomly assigned to the control (n = 16) or intervention (n = 16) group. During a DLS, all participants demonstrated knee valgus that was corrected with a heel lift.
  
  
  METHODS
  The intervention group completed 10 sessions of directed exercise that focused on hip and ankle strength and flexibility over a 2- to 3-week period.
  
  
  METHODS
  We assessed MKD and 3D knee valgus during the DLS using an electromagnetic tracking system. Hip strength and ankle-dorsiflexion range of motion were measured. Change scores were calculated for MKD and 3D valgus at 0%, 10%, 20%, 30%, 40%, and 50% phases, and group (2 levels)-by phase (6 levels) repeated-measures analyses of variance were conducted. Independent t tests were used to compare change scores in other variables (α < .05).
  
  
  RESULTS
  The MKD decreased from 20% to 50% of the DLS (P = .02) and 3D knee valgus improved from 30% to 50% of the squat phase (P = .001). Ankle-dorsiflexion range of motion (knee extended) increased in the intervention group (P = .009). No other significant findings were observed (P > .05).
  
  
  CONCLUSIONS
  The intervention reduced MKD and 3D knee valgus during a DLS. The intervention also increased ankle range of motion. Our inclusion criteria might have limited our ability to observe changes in hip strength.
authors.affiliation: Department of Kinesiology, Department of Orthopedics and Rehabilitation, University of Wisconsin-Madison, 2031 Gymnasium-Natatorium, 2000 Observatory Dr, Madison, WI 53706, USA. drbell2@wisc.edu
authors.forename: David R
authors.initials: DR
authors.lastname: Bell
authors.forename: D Craig
authors.initials: DC
authors.lastname: Oates
authors.forename: Micheal A
authors.initials: MA
authors.lastname: Clark
authors.forename: Darin A
authors.initials: DA
authors.lastname: Padua
mesh_terms: D000328:Adult; D000704:Analysis of Variance; D000843:Ankle Joint / Q000502:physiology; D005081:Exercise Therapy; D005260:Female; D006621:Hip Joint / Q000502:physiology; D006801:Humans; D007719:Knee Joint / Q000503:physiopathology*; D008297:Male; D009068:Movement / Q000502:physiology; D011187:Posture / Q000502:physiology; D016059:Range of Motion, Articular / Q000502:physiology; D055815:Young Adult