title: Modifying the shoulder joint position during shrugging and retraction exercises alters the activation of the medial scapular muscles.
abstract: BACKGROUND
  In patients with shoulder or neck pain, often an imbalance of the activation in the scapular upward and downward rotators is present which can cause abnormalities in coordinated scapular rotation. Shrug exercises are often recommended to activate muscles that produce upward rotation, but little information is available on the activity of the downward rotators during shrugging exercises. The position used for the shrug exercise may affect the relative participation of the medial scapular rotators.
  
  
  OBJECTIVE
  To compare muscle activity, using both surface and fine-wire electrodes, of the medial scapular muscles during different shoulder joint positions while performing shrug and retraction exercises.
  
  
  METHODS
  Controlled laboratory study.
  
  
  METHODS
  Twenty-six subjects performed 3 different exercises: shrug with the arms at the side while holding a weight ("Shrug"), shrug with arms overhead and retraction with arms overhead. EMG data with surface and fine wire electrodes was collected from the Upper Trapezius (UT), Levator Scapulae (LS), Middle Trapezius (MT), Rhomboid Major (RM) and Lower Trapezius (LT).
  
  
  RESULTS
  The results showed that activity levels of the main medial scapular muscles depend upon the specific shoulder joint position when performing shrug and retraction exercises. High UT activity was found across all exercises, with no significant differences in UT activity between the exercises. The LS and RM activity was significantly lower during "ShrugOverhead" and the RM, MT and LT activity was significantly higher during "RetractionOverhead".
  
  
  CONCLUSIONS
  This study has identified that all three exercises elicited similar UT activity. LS and RM activity is decreased with the "ShrugOverhead" exercise. The "RetractionOverhead" was the most effective exercise in activating the medial scapular muscles.
authors.affiliation: Department of Rehabilitation Sciences and Physiotherapy, Faculty of Medicine and Health Sciences, University Hospital, Ghent, Belgium. Electronic address: Birgit.Castelein@ugent.be.
authors.forename: Birgit
authors.initials: B
authors.lastname: Castelein
authors.affiliation: Department of Rehabilitation Sciences and Physiotherapy, Faculty of Medicine and Health Sciences, University Hospital, Ghent, Belgium.
authors.forename: Ann
authors.initials: A
authors.lastname: Cools
authors.affiliation: Department of Physical Medicine and Orthopedic Surgery, University Hospital, Ghent, Belgium.
authors.forename: Thierry
authors.initials: T
authors.lastname: Parlevliet
authors.affiliation: Department of Rehabilitation Sciences and Physiotherapy, Faculty of Medicine and Health Sciences, University Hospital, Ghent, Belgium.
authors.forename: Barbara
authors.initials: B
authors.lastname: Cagnie
mesh_terms: D005081:Exercise Therapy / Q000379:methods*; D005260:Female; D006801:Humans; D008297:Male; D019547:Neck Pain / Q000503:physiopathology / Q000628:therapy*; D012399:Rotation; D012540:Scapula / Q000502:physiology*; D012785:Shoulder Joint / Q000502:physiology*; D020069:Shoulder Pain / Q000503:physiopathology / Q000628:therapy*; D064171:Superficial Back Muscles / Q000502:physiology*
keywords: Exercises; Fine-wire EMG; Scapula; Surface EMG