title: Do dorsal head contact forces have the potential to identify impairment during graded craniocervical flexor muscle contractions?
abstract: OBJECTIVE
  To determine if the force exerted onto the supporting surface by the dorsal head during graded contractions of isometric craniocervical flexion (ICCF) in the supine position has the potential to measure aberrant muscle performance between participant groups with and without painful neck disorders.
  
  
  METHODS
  Cross-sectional, between-participant study of the force exerted by the head on the supporting surface during ICCF muscle contractions.
  
  
  METHODS
  Research laboratory.
  
  
  METHODS
  Thirty-two participants with a history of neck pain and 32 asymptomatic control participants.
  
  
  METHODS
  Not applicable.
  
  
  METHODS
  Dorsal head force (DHF), which is the force (in newtons) exerted by the head on the supporting surface during ICCF muscle contractions in the supine position. ICCF muscle contractions were performed at maximal voluntary contraction (MVC), and sustained at contractions of 50% of MVC and 20% of MVC.
  
  
  RESULTS
  Both neck pain and control participants significantly increased their DHF on the supporting surface from resting values during all ICCF muscle contractions (P<.001). No differences in DHF were found between symptomatic and control participants during any of the ICCF efforts.
  
  
  CONCLUSIONS
  It would appear that DHF exerted on the supporting surface during graded ICCF muscle contractions is similar between neck pain sufferers and control participants, and is therefore limited in its usefulness as a measurement of abnormal performance.
authors.affiliation: Division of Physiotherapy, University of Queensland, Brisbane, Australia. s.oleary@shrs.uq.edu.au
authors.forename: Shaun
authors.initials: S
authors.lastname: O'Leary
authors.forename: Gwendolen
authors.initials: G
authors.lastname: Jull
authors.forename: Bill
authors.initials: B
authors.lastname: Vicenzino
mesh_terms: D000328:Adult; D016022:Case-Control Studies; D002574:Cervical Vertebrae / Q000502:physiology*; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D007537:Isometric Contraction / Q000502:physiology*; D008297:Male; D009126:Muscle Relaxation / Q000502:physiology; D018482:Muscle, Skeletal / Q000502:physiology; D019547:Neck Pain / Q000175:diagnosis* / Q000534:rehabilitation*; D010147:Pain Measurement; D026741:Physical Therapy Modalities; D011336:Probability; D016059:Range of Motion, Articular / Q000502:physiology; D012016:Reference Values; D016896:Treatment Outcome