title: Passive knee-extension test to measure hamstring tightness: influence of gravity correction.
abstract: BACKGROUND
  A passive knee-extension test has been shown to be a reliable method of assessing hamstring tightness, but this method does not take into account the potential effect of gravity on the tested leg.
  
  
  OBJECTIVE
  To compare an original passive knee-extension test with 2 adapted methods including gravity's effect on the lower leg.
  
  
  METHODS
  Repeated measures.
  
  
  METHODS
  Laboratory.
  
  
  METHODS
  20 young track and field athletes (16.6 ± 1.6 y, 177.6 ± 9.2 cm, 75.9 ± 24.8 kg).
  
  
  METHODS
  Each subject was tested in a randomized order with 3 different methods: In the original one (M1), passive knee angle was measured with a standard force of 68.7 N (7 kg) applied proximal to the lateral malleolus. The second (M2) and third (M3) methods took into account the relative lower-leg weight (measured respectively by handheld dynamometer and anthropometrical table) to individualize the force applied to assess passive knee angle.
  
  
  METHODS
  Passive knee angles measured with video-analysis software.
  
  
  RESULTS
  No difference in mean individualized applied force was found between M2 and M3, so the authors assessed passive knee angle only with M2. The mean knee angle was different between M1 and M2 (68.8 ± 12.4 vs 73.1 ± 10.6, P < .001). Knee angles in M1 and M2 were correlated (r = .93, P < .001).
  
  
  CONCLUSIONS
  Differences in knee angle were found between the original passive knee-extension test and a method with gravity correction. M2 is an improved version of the original method (M1) since it minimizes the effect of gravity. Therefore, we recommend using it rather than M1.
authors.affiliation: HECVSanté Dept of Physiotherapy, University of Applied Sciences of Western Switzerland, Lausanne, Switzerland.
authors.forename: Kenny
authors.initials: K
authors.lastname: Guex
authors.forename: Francois
authors.initials: F
authors.lastname: Fourchet
authors.forename: Heiko
authors.initials: H
authors.lastname: Loepelt
authors.forename: Gregoire P
authors.initials: GP
authors.lastname: Millet
mesh_terms: D000293:Adolescent; D000886:Anthropometry / Q000379:methods*; D006112:Gravitation; D006801:Humans; D007719:Knee Joint / Q000502:physiology*; D007866:Leg; D008297:Male; D009129:Muscle Tonus / Q000502:physiology*; D018482:Muscle, Skeletal / Q000502:physiology*; D016059:Range of Motion, Articular / Q000502:physiology*; D013848:Thigh