title: Differentiation of gluteus medius and minimus activity in weight bearing and non-weight bearing exercises by M-mode ultrasound imaging.
abstract: BACKGROUND
  Knowledge on task-specific activity of the deep hip abductor muscles is limited and is required for determining appropriate hip abductor exercises.
  
  
  OBJECTIVE
  To assess the temporal differentiation of activity of gluteus minimus and the deep and the superficial regions of gluteus medius during weight bearing and non-weight bearing exercises.
  
  
  METHODS
  Repeated measures design on a single recording occasion.
  
  
  METHODS
  M-mode ultrasound was used to capture activity-related muscle motion of the gluteus minimus and medius muscles in 20 healthy volunteers during weight shift, hip hitch, side-lying abduction and active leg lengthening exercises. M-mode traces were computer-processed for detecting muscle motion onsets. Mean onset differences between muscle regions and their intra-individual variability were assessed.
  
  
  RESULTS
  In contrast to side-lying abduction, the weight shift and hip hitch exercises resulted in larger onset variability between the gluteus minimus and deep gluteus medius (P < 0.001) and also between the deep and superficial regions of the gluteus medius (P < 0.05).
  
  
  CONCLUSIONS
  Weight bearing exercises promoted a greater functional differentiation between deep and superficial hip abductor muscles.
authors.affiliation: Pain Clinic, Center for Anesthesiology, Emergency and Intensive Care Medicine, University Hospital Göttingen, Göttingen, Germany. Electronic address: angela.dieterich@bccn.uni-goettingen.de.
authors.forename: A
authors.initials: A
authors.lastname: Dieterich
authors.affiliation: Pain Clinic, Center for Anesthesiology, Emergency and Intensive Care Medicine, University Hospital Göttingen, Göttingen, Germany.
authors.forename: F
authors.initials: F
authors.lastname: Petzke
authors.affiliation: School of Physiotherapy and Exercise Science, Faculty of Health Sciences, Curtin University, Perth, Australia.
authors.forename: C
authors.initials: C
authors.lastname: Pickard
authors.affiliation: School of Physiotherapy and Exercise Science, Faculty of Health Sciences, Curtin University, Perth, Australia.
authors.forename: P
authors.initials: P
authors.lastname: Davey
authors.affiliation: Pain Clinic, Center for Anesthesiology, Emergency and Intensive Care Medicine, University Hospital Göttingen, Göttingen, Germany; Department of Neurorehabilitation Engineering, Bernstein Center for Computational Neuroscience, Göttingen, Germany.
authors.forename: D
authors.initials: D
authors.lastname: Falla
mesh_terms: D000328:Adult; D000368:Aged; D002081:Buttocks; D015331:Cohort Studies; D005260:Female; D006621:Hip Joint / Q000502:physiology*; D006801:Humans; D008875:Middle Aged; D009119:Muscle Contraction / Q000502:physiology; D053580:Muscle Strength / Q000502:physiology; D018482:Muscle, Skeletal / Q000502:physiology*; D056888:Patient Positioning; D016059:Range of Motion, Articular / Q000502:physiology*; D018608:Ultrasonography, Doppler / Q000379:methods*; D016474:Weight-Bearing / Q000502:physiology
keywords: Hip; Therapeutic exercise; Ultrasound; Variability