title: Neck muscle fatigue differentially alters scapular and humeral kinematics during humeral elevation in subclinical neck pain participants versus healthy controls.
abstract: BACKGROUND
  Scapular orientation is highly dependent on axioscapular muscle function. This study examined the impact of neck muscle fatigue on scapular and humeral kinematics in participants with and without subclinical neck pain (SCNP) during humeral elevation.
  
  
  METHODS
  Ten SCNP and 10 control participants performed three unconstrained trials of dominant arm humeral elevation in the scapular plane to approximately 120 degrees before and after neck extensor muscle fatigue. Three-dimensional scapular and humeral kinematics were measured during the humeral elevation trials.
  
  
  RESULTS
  Humeral elevation plane angle showed a significant interaction between groups (SCNP vs controls) and trial (pre- vs post-fatigue) (p=0.001). Controls began the unconstrained humeral elevation task after fatigue in a more abducted position, (p=0.002). Significant baseline differences in scapular rotation existed between the two groups (Posterior/Anterior tilt, p=0.04; Internal/External Rotation, p=0.001).
  
  
  CONCLUSIONS
  SCNP contributed to altered scapular kinematics. Neck muscle fatigue influenced humeral kinematics in controls but not the SCNP group; suggesting that altered scapular motor control in the SCNP group resulted in an impaired adaption further to the neck muscle fatigue.
authors.affiliation: Faculty of Health Sciences, University of Ontario Institute of Technology, 2000 Simcoe St. North, Oshawa, ON L1H 7K4, Canada. Electronic address: mahboobeh.zabihhosseinian@uoit.net.
authors.forename: Mahboobeh
authors.initials: M
authors.lastname: Zabihhosseinian
authors.affiliation: Faculty of Health Sciences, University of Ontario Institute of Technology, 2000 Simcoe St. North, Oshawa, ON L1H 7K4, Canada; Department of Kinesiology, Brock University, Niagara Region, 1812 Sir Isaac Brock Way, St. Catharines, ON L2S 3A1, Canada.
authors.forename: Michael W R
authors.initials: MW
authors.lastname: Holmes
authors.affiliation: Department of Graduate Studies, Canadian Memorial Chiropractic College, 6100 Leslie St, North York, ON M2H 3J1, Canada.
authors.forename: Samuel
authors.initials: S
authors.lastname: Howarth
authors.affiliation: Department of Graduate Studies, Canadian Memorial Chiropractic College, 6100 Leslie St, North York, ON M2H 3J1, Canada.
authors.forename: Brad
authors.initials: B
authors.lastname: Ferguson
authors.affiliation: Faculty of Health Sciences, University of Ontario Institute of Technology, 2000 Simcoe St. North, Oshawa, ON L1H 7K4, Canada. Electronic address: bernadette.murphy@uoit.ca.
authors.forename: Bernadette
authors.initials: B
authors.lastname: Murphy
mesh_terms: D000328:Adult; D001696:Biomechanical Phenomena; D016022:Case-Control Studies; D005260:Female; D006801:Humans; D006811:Humerus / Q000502:physiology* / Q000503:physiopathology; D008297:Male; D018763:Muscle Fatigue; D009334:Neck Muscles / Q000502:physiology* / Q000503:physiopathology; D019547:Neck Pain / Q000503:physiopathology*; D012540:Scapula / Q000502:physiology* / Q000503:physiopathology
keywords: Glenohumeral impingement; Motor control; Neck fatigue; Shoulder dyskinesia; Shoulder kinematics; Subclinical neck pain