title: Comparison between tests of fatigue and force for trunk flexion.
abstract: METHODS
  A quasi-experimental study was conducted.
  
  
  OBJECTIVE
  To compare intraindividual differences between trunk flexion isometric force, fatigue during isometric contraction (isometric fatigue), and fatigue during sit-ups (dynamic fatigue).
  
  
  BACKGROUND
  Trunk flexion force and trunk flexion fatigue commonly are used to assess trunk flexion fitness. The use of one test is appropriate only if the tests are highly correlated.
  
  
  METHODS
  This study measured force and either isometric fatigue (time to task failure, n = 79) or dynamic fatigue (number of sit-ups in 2 minutes, n = 73) in self-selected, healthy secondary school (I-III) subjects. In 15 subjects, both isometric and dynamic fatigue were measured.
  
  
  RESULTS
  After control was used for upper body mass, the R2(adj) was 0.34 between isometric force and isometric fatigue, 0.31 between isometric force and dynamic fatigue was, and 0.27 between dynamic fatigue and isometric fatigue. Including gender in the model did not affect the results.
  
  
  CONCLUSIONS
  The lack of a high correlation between trunk flexion isometric fatigue, dynamic fatigue, and isometric force suggests that health care professionals should be careful to select the test that answers their particular needs or question.
authors.affiliation: Centre for Clinical Epidemiology and Community Studies, SMBD-Jewish General Hospital, McGill University, Montreal, QC H3T 1E2, Canada. ian.shrier@mcgill.ca
authors.forename: Ian
authors.initials: I
authors.lastname: Shrier
authors.forename: Debbie
authors.initials: D
authors.lastname: Feldman
authors.forename: Jackie
authors.initials: J
authors.lastname: Klvana
authors.forename: Michel
authors.initials: M
authors.lastname: Rossignol
authors.forename: Lucien
authors.initials: L
authors.lastname: Abenhaim
mesh_terms: D000005:Abdomen / Q000502:physiology*; D000293:Adolescent; D001827:Body Height; D001835:Body Weight; D015331:Cohort Studies; D015444:Exercise / Q000502:physiology*; D005260:Female; D006801:Humans; D007537:Isometric Contraction / Q000502:physiology*; D008297:Male; D018763:Muscle Fatigue / Q000502:physiology*; D017678:Sex Distribution; D013909:Thorax / Q000502:physiology*