title: Differences in isometric neck muscle strength between healthy controls and women with chronic neck pain: the use of a reliable measurement.
abstract: OBJECTIVE
  To determine the intra- and interrater reliability of the Biodex isokinetic dynamometer to measure the maximal isometric strength of the cervical flexors and extensors, to develop an age- and sex-based normative database in a healthy population, and to evaluate the differences in neck strength between women with chronic neck pain and healthy controls.
  
  
  METHODS
  Cross-sectional.
  
  
  METHODS
  Physical and rehabilitation medicine department.
  
  
  METHODS
  Ninety-six healthy volunteers (4 age groups: 20-29, 30-39, 40-49, 50-59y; each consisting of 12 men and 12 women) and 30 women with chronic neck pain.
  
  
  METHODS
  Not applicable.
  
  
  METHODS
  Peak isometric strength of the cervical muscles was tested for flexion and extension by using the Biodex isokinetic dynamometer. The intra- and interrater reliability of the protocol was evaluated in 12 volunteers.
  
  
  RESULTS
  The reliability for strength was high for both flexion and extension (intraclass correlation coefficient, .92-.96). The mean peak torque for flexion and extension was significantly higher in men (24Nm, 36.4Nm, respectively) compared with women (16.6Nm, 26.5Nm, respectively) (P<.001). Peak torque production for extension was significantly lower in the patient group (22.3Nm) compared with the healthy female control group (26.5Nm) (P=.003). No significant differences in flexion strength between patient and female control group were found.
  
  
  CONCLUSIONS
  Results show a high degree of intra- and interrater reliability in measuring isometric neck muscle strength when using the Biodex isokinetic dynamometer. The use of normative data for neck strength when evaluating patients with neck disorders needs to take sex into account. The current study has shown that women with chronic neck pain have lower neck muscle strength in extension than the healthy female group.
authors.affiliation: Department of Rehabilitation Sciences and Physiotherapy, Ghent University, Ghent, Belgium.
authors.forename: Barbara
authors.initials: B
authors.lastname: Cagnie
authors.forename: Ann
authors.initials: A
authors.lastname: Cools
authors.forename: Veerle
authors.initials: V
authors.lastname: De Loose
authors.forename: Dirk
authors.initials: D
authors.lastname: Cambier
authors.forename: Lieven
authors.initials: L
authors.lastname: Danneels
mesh_terms: D000328:Adult; D005260:Female; D006801:Humans; D007537:Isometric Contraction / Q000502:physiology*; D008297:Male; D008875:Middle Aged; D053580:Muscle Strength / Q000502:physiology*; D053581:Muscle Strength Dynamometer / Q000706:statistics & numerical data*; D009334:Neck Muscles / Q000503:physiopathology; D019547:Neck Pain / Q000503:physiopathology / Q000534:rehabilitation*; D015588:Observer Variation; D012016:Reference Values; D015203:Reproducibility of Results; D012737:Sex Factors