title: Alterations of scapular kinematics and associated muscle activation specific to symptomatic dyskinesis type after conscious control.
abstract: BACKGROUND
  Scapular orientation and movements can affect the function of the shoulder. However, evidence is limited on whether symptomatic subjects can actively maintain the scapula in a neutral position through conscious control.
  
  
  OBJECTIVE
  To investigate whether symptomatic subjects with scapular dyskinesis can achieve optimal scapular movements and associated muscle activities through conscious control.
  
  
  METHODS
  A cross-sectional study.
  
  
  METHODS
  Sixty subjects with scapular dyskinesis (16 inferior angle pattern I, 16 medial border pattern II, and 28 mixed pattern) performed 3 selected exercises (arm elevation, side-lying elevation, and side-lying external rotation) with and without conscious control. Three-dimensional electromagnetic motion and electromyography were used to record the scapular kinematics and muscle activation during the exercises.
  
  
  RESULTS
  For scapular kinematics, significant increases in scapular external rotation (4.6 ± 3.2°, p < 0.0125) were found with conscious control during arm elevation and side-lying elevation in three groups. Significant increases in activation of the middle and lower trapezius (MT: 4.9 ± 2.4% MVIC; LT: 10.2 ± 6.8% MVIC, p < 0.0 25) were found with conscious control in 3 exercises among the 3 dyskinesis groups. Increased serratus anterior activation (SA: 11.2 ± 4.8% MVIC, p < 0.0 25) was found in the concentric phase of side-lying external rotation in the pattern I and I + II groups.
  
  
  CONCLUSIONS
  Conscious control of the scapula can alter scapular orientation and MT, LT, and SA activation during 3 selected exercises in subjects with symptomatic dyskinesis. Specifically, conscious control during side-lying external rotation can be applied to increase SA activity in pattern I and I + II dyskinesis.
authors.affiliation: School and Graduate Institute of Physical Therapy, College of Medicine, National Taiwan University, Taiwan, ROC.
authors.forename: Hsiang-Ling
authors.initials: HL
authors.lastname: Ou
authors.affiliation: School and Graduate Institute of Physical Therapy, College of Medicine, National Taiwan University, Taiwan, ROC.
authors.forename: Tsun-Shun
authors.initials: TS
authors.lastname: Huang
authors.affiliation: School and Graduate Institute of Physical Therapy, College of Medicine, National Taiwan University, Taiwan, ROC.
authors.forename: Yu-Ting
authors.initials: YT
authors.lastname: Chen
authors.affiliation: Department of Physical Therapy and Assistive Technology, National Yang-Ming University, Taiwan, ROC.
authors.forename: Wen-Yin
authors.initials: WY
authors.lastname: Chen
authors.affiliation: Department of Physical Medicine and Rehabilitation, National Taiwan University Hospital, Taiwan, ROC.
authors.forename: Yu-Li
authors.initials: YL
authors.lastname: Chang
authors.affiliation: Institute of Biomedical Engineering, National Taiwan University, Taiwan, ROC.
authors.forename: Tung-Wu
authors.initials: TW
authors.lastname: Lu
authors.affiliation: Institute of Biomedical Engineering, National Taiwan University, Taiwan, ROC.
authors.forename: Ting-Han
authors.initials: TH
authors.lastname: Chen
authors.affiliation: School and Graduate Institute of Physical Therapy, College of Medicine, National Taiwan University, Taiwan, ROC. Electronic address: jiujlin@ntu.edu.tw.
authors.forename: Jiu-Jenq
authors.initials: JJ
authors.lastname: Lin
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001696:Biomechanical Phenomena / Q000502:physiology*; D003243:Consciousness; D003430:Cross-Sectional Studies; D020820:Dyskinesias / Q000628:therapy*; D005081:Exercise Therapy / Q000379:methods*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009068:Movement / Q000502:physiology*; D009119:Muscle Contraction / Q000502:physiology*; D012540:Scapula / Q000503:physiopathology*
keywords: Conscious control; Scapular dyskinesis; Serratus anterior; Trapezius