title: Knee valgus during drop jumps in National Collegiate Athletic Association Division I female athletes: the effect of a medial post.
abstract: BACKGROUND
  Female athletes land from a jump with greater knee valgus and ankle pronation/eversion. Excessive valgus and pronation have been linked to risk of anterior cruciate ligament injury. A medially posted orthosis decreases component motions of knee valgus such as foot pronation/eversion and tibial internal rotation.
  
  
  OBJECTIVE
  We hypothesized a medial post would decrease knee valgus and ankle pronation/eversion during drop-jump landings in NCAA-I female athletes.
  
  
  METHODS
  Controlled laboratory study.
  
  
  METHODS
  Knee and ankle 3-dimensional kinematics were measured using high-speed motion capture in 10 National Collegiate Athletic Association Division I female athletes during a drop-jump landing with and without a medial post. Analysis of variance was used to determine differences in posting condition, t tests were used to determine dominant-nondominant differences, and the Pearson correlation coefficient was used to determine relationships between variables.
  
  
  RESULTS
  Significant differences were found for all measures in the posted condition. A medial post decreased knee valgus at initial contact (1.24 degrees , P < .01) and maximum angle (1.21 degrees , P < .01). The post also decreased ankle pronation/eversion at initial contact (0.77 degrees , P < .01) and maximum angle (0.95 degrees , P = .039).
  
  
  CONCLUSIONS
  The authors have demonstrated a significant decrease in knee valgus and ankle pronation/eversion during a drop jump with a medial post placed in the athletes' shoes.
  
  
  CONCLUSIONS
  A medial post may be a potential means to decrease risk of anterior cruciate ligament injury.
authors.affiliation: Department of Kinesiology, University of Connecticut, Storrs, Connecticut, USA. mickpt@sbcglobal.net
authors.forename: Michael
authors.initials: M
authors.lastname: Joseph
authors.forename: David
authors.initials: D
authors.lastname: Tiberio
authors.forename: Jennifer L
authors.initials: JL
authors.lastname: Baird
authors.forename: Thomas H
authors.initials: TH
authors.lastname: Trojian
authors.forename: Jeffrey M
authors.initials: JM
authors.lastname: Anderson
authors.forename: William J
authors.initials: WJ
authors.lastname: Kraemer
authors.forename: Carl M
authors.initials: CM
authors.lastname: Maresh
mesh_terms: D000328:Adult; D000843:Ankle Joint / Q000502:physiology; D001696:Biomechanical Phenomena; D018592:Cross-Over Studies; D005260:Female; D006801:Humans; D007719:Knee Joint / Q000502:physiology*; D009068:Movement / Q000502:physiology*; D009989:Orthotic Devices; D012399:Rotation; D012775:Shoes; D013177:Sports / Q000502:physiology*