title: Maximal voluntary isometric neck strength deficits in adults with whiplash-associated disorders and association with pain and fear of movement.
abstract: METHODS
  Controlled laboratory study using a cross-sectional, repeated-measures design.
  
  
  OBJECTIVE
  To quantify maximal voluntary isometric neck forces in healthy subjects and individuals with whiplash-associated disorder (WAD), using an objective measurement system to evaluate the test-retest properties of these strength measurements and to assess the links between neck strength, pain, kinesiophobia, and catastrophizing in patients with WAD.
  
  
  BACKGROUND
  The prognosis of WAD is difficult to predict due to a lack of objective measurement methods and to our limited understanding of the role of psychological factors in the development of chronic WAD symptoms.
  
  
  METHODS
  Fourteen subjects with chronic WAD grade I or II and an age-matched, healthy group (n = 28) participated in this study. Cervical strength was measured with the Multi-Cervical Unit (MCU) in 6 directions, and pain was measured with a visual analog scale. Individuals in the WAD group completed the Neck Disability Index (NDI), the Tampa Scale for Kinesiophobia (TSK), and the Pain Catastrophizing Scale (PCS).
  
  
  RESULTS
  Significant deficits in strength were observed for the individuals in the WAD group compared to the healthy group, particularly in extension, retraction, and left lateral flexion (P<.05). The MCU demonstrated good intratester reliability for the healthy group (ICC = 0.80-0.92) and the WAD group (ICC = 0.85-0.98), and small standard errors of measurement for both groups. No significant association was found between neck strength and NDI, TSK, and PCS.
  
  
  CONCLUSIONS
  The MCU demonstrated good test-retest properties for healthy subjects and individuals with WAD. Cervical strength was lower in individuals with WAD; however, the strength deficits were not clearly linked with psychological factors.
authors.affiliation: Constance-Lethbridge Rehabilitation Center, Montreal, Canada.
authors.forename: Isabelle
authors.initials: I
authors.lastname: Pearson
authors.forename: Alison
authors.initials: A
authors.lastname: Reichert
authors.forename: Sophie J
authors.initials: SJ
authors.lastname: De Serres
authors.forename: Jean-Pierre
authors.initials: JP
authors.lastname: Dumas
authors.forename: Julie N
authors.initials: JN
authors.lastname: Côté
mesh_terms: D000328:Adult; D000704:Analysis of Variance; D016022:Case-Control Studies; D003430:Cross-Sectional Studies; D005239:Fear; D005260:Female; D019416:Head Movements; D006801:Humans; D007537:Isometric Contraction / Q000502:physiology; D008297:Male; D008875:Middle Aged; D010146:Pain / Q000503:physiopathology* / Q000523:psychology*; D010147:Pain Measurement; D011379:Prognosis; D016059:Range of Motion, Articular; D015203:Reproducibility of Results; D014911:Whiplash Injuries / Q000503:physiopathology* / Q000523:psychology*