title: Isometric strength assessment, Part II: Static testing does not accurately classify validity of effort.
abstract: OBJECTIVE
  The purpose of this study was to determine if these two commonly-administered isometric tests are accurate indices of effort.
  
  
  METHODS
  34 healthy subjects were tested once giving a maximum voluntary effort and once attempting to feign weakness of 50% of maximum.
  
  
  RESULTS
  During feigned weakness sessions, 20 of 34 subjects (58.5%), produced CVs of 15% or less during the Leg Lift. At the 95% CI, the expected frequency of false negatives for feigned weakness is 42.3 to 75.3% for the Leg Lift. At the 95% CI, the expected frequency of false negatives for feigned weakness is 51.9% to 83.3% for the Arm Lift.
  
  
  CONCLUSIONS
  Neither isometric lift is appropriate for classifying validity of effort. Use of these isometric lifts should be discontinued for the assessment of effort.
authors.affiliation: WCS Occupational Rehabilitation Sports Medicine, Naperville, IL, USA.
authors.forename: Robert
authors.initials: R
authors.lastname: Townsend
authors.forename: Darrell W
authors.initials: DW
authors.lastname: Schapmire
authors.forename: James
authors.initials: J
authors.lastname: St James
authors.forename: Larry
authors.initials: L
authors.lastname: Feeler
mesh_terms: D000328:Adult; D001519:Behavior; D005260:Female; D006801:Humans; D007537:Isometric Contraction / Q000502:physiology*; D008297:Male; D053580:Muscle Strength; D053581:Muscle Strength Dynamometer; D005082:Physical Exertion; D015203:Reproducibility of Results; D014938:Work Capacity Evaluation