title: Differences in lower extremity kinematics between a bilateral drop-vertical jump and a single-leg step-down.
abstract: METHODS
  Mixed-model, repeated-measures design in a laboratory setting.
  
  
  OBJECTIVE
  To examine the differences in hip, knee, and ankle kinematics between a bilateral drop-vertical jump and single-leg step-down. A secondary purpose was to examine gender differences in kinematics of the tasks.
  
  
  BACKGROUND
  Both a drop-vertical jump and step-down task have been used to evaluate lower extremity movement and injury risk. The differences in joint angles between these tasks have not been reported.
  
  
  METHODS
  Three-dimensional joint angles of the hip, knee, and ankle of 19 females and 18 males were evaluated with a high-speed camera system while the subjects performed a bilateral drop-vertical jump and a single-leg step-down. Maximum joint angles were compared between tasks and genders using ANOVA models. eversion (12 degrees compared to 8 degrees) (P<.0005) and hip adduction (16 degrees compared to 1 degrees) (P= .03) than the drop-vertical jump. Females had greater hip internal rotation in the step-down than in the drop-vertical jump (5 degrees compared to 2 degrees) (P = .02). When averaged across both tasks, females had greater knee abduction than males in both tasks (4 degrees compared to 0 degrees) (P<.0005).
  
  
  CONCLUSIONS
  The unilateral step-down task produced greater motion in the frontal and transverse planes at the ankle and hip, and would be appropriate in evaluating control of the hip. The bilateral drop-vertical jump produced greater knee abduction in both genders and may be appropriate for evaluating excessive knee abduction as a risk factor for noncontact anterior cruciate ligament injury, for example. The 2 tasks appear to challenge the neuromuscular system in different manners, and both should continue to be used in the investigation of injury risk.
authors.affiliation: Department of Human Movement Sciences, University of Wisconsin-Milwaukee, Milwaukee, WI, USA. jearl@uwm.edu
authors.forename: Jennifer E
authors.initials: JE
authors.lastname: Earl
authors.forename: Sarika K
authors.initials: SK
authors.lastname: Monteiro
authors.forename: Kelli R
authors.initials: KR
authors.lastname: Snyder
mesh_terms: D000328:Adult; D000704:Analysis of Variance; D000070598:Anterior Cruciate Ligament Injuries; D001696:Biomechanical Phenomena; D005260:Female; D006621:Hip Joint / Q000502:physiology; D006801:Humans; D007718:Knee Injuries / Q000503:physiopathology / Q000517:prevention & control*; D007719:Knee Joint / Q000502:physiology; D035002:Lower Extremity / Q000502:physiology*; D008297:Male; D009068:Movement / Q000502:physiology*; D010781:Photography