title: Experimentally reduced hip-abductor muscle strength and frontal-plane biomechanics during walking.
abstract: BACKGROUND
  Researchers have postulated that reduced hip-abductor muscle strength may have a role in the progression of knee osteoarthritis by increasing the external knee-adduction moment. However, the relationship between hip-abductor strength and frontal-plane biomechanics remains unclear.
  
  
  OBJECTIVE
  To experimentally reduce hip-abduction strength and observe the subsequent changes in frontal-plane biomechanics.
  
  
  METHODS
  Descriptive laboratory study.
  
  
  METHODS
  Research laboratory.
  
  
  METHODS
  Eight healthy, recreationally active men (age = 27 ± 6 years, height = 1.75 ± 0.11 m, mass = 76.1 ± 10.0 kg).
  
  
  METHODS
  All participants underwent a superior gluteal nerve block injection to reduce the force output of the hip-abductor muscle group.
  
  
  METHODS
  Maximal isometric hip-abduction strength and gait biomechanical data were collected before and after the injections. Gait biomechanical variables collected during walking consisted of knee- and hip-adduction moments and impulses and the peak angles of contralateral pelvic drop, hip adduction, and ipsilateral trunk lean.
  
  
  RESULTS
  Hip-abduction strength was reduced after the injection (P = .001) and remained lower than baseline values at the completion of the postinjection gait data collection (P = .02). No alterations in hip- or knee-adduction moments (hip: P = .11; knee: P = .52) or impulses (hip: P = .16; knee: P = .41) were found after the nerve block. Similarly, no changes in angular kinematics were observed for contralateral pelvic drop (P = .53), ipsilateral trunk lean (P = .78), or hip adduction (P = .48).
  
  
  CONCLUSIONS
  A short-term reduction in hip-abductor strength was not associated with alterations in the frontal-plane gait biomechanics of young, healthy men. Further research is needed to determine whether a similar relationship is true in older adults with knee osteoarthritis.
authors: Department of Kinesiology and Health Promotion, University of Kentucky, Lexington.
authors: Michael B
authors: MB
authors: Pohl
authors: Karen D
authors: KD
authors: Kendall
authors: Chirag
authors: C
authors: Patel
authors: J Preston
authors: JP
authors: Wiley
authors: Carolyn
authors: C
authors: Emery
authors: Reed
authors: R
authors: Ferber
mesh_terms: D000328:Adult; D001696:Biomechanical Phenomena / Q000502:physiology; D005684:Gait / Q000502:physiology; D064368:Healthy Volunteers; D006621:Hip Joint / Q000502:physiology; D006801:Humans; D007717:Knee / Q000502:physiology; D007719:Knee Joint / Q000502:physiology; D008297:Male; D053580:Muscle Strength / Q000502:physiology*; D018482:Muscle, Skeletal / Q000502:physiology*; D020370:Osteoarthritis, Knee / Q000209:etiology / Q000503:physiopathology; D010388:Pelvis / Q000502:physiology; D060726:Torso / Q000502:physiology; D016138:Walking / Q000502:physiology*
keywords: gait analysis; kinematics; knee; moment; pelvic drop