title: Hand-held dynamometry: tester strength is paramount, even in frail populations.
abstract: OBJECTIVE
  To determine test-retest and inter-rater reliability of hand-held dynamometry when used to measure knee--extensor strength in patients with advanced cancer.
  
  
  METHODS
  Adults with metastatic or locally advanced cancer recruited from palliative care services to a study of the risk factors for falls.
  
  
  METHODS
  Consecutive recruits (n = 30) underwent repeat testing after an interval of 1 h, by the same researcher, to assess test-retest reliability. The subsequent 15 patients underwent retesting by a second researcher. The intra-class correlation coefficient and limits of agreement were calculated.
  
  
  RESULTS
  The test-retest reliability difference between measurements increased with the magnitude of measurement, mean leg strength = 113 N (standard deviation 43.1), 95% ratio limits of agreement 0.81-1.5, intra-class correlation coefficient = 0.9. The inter-rater testing mean leg strength = 128.5 N (standard deviation 35.1), 95% limits of agreement = -57.24 to 36.06 N. Intra-class correlation coefficient = 0.83.
  
  
  CONCLUSIONS
  Test-retesting and inter-rater testing yielded high intra-class correlation coefficients, but the limits of agreement were wide. In test-retesting, the difference between tests increased as the magnitude of measurement increased. It has been widely reported that hand-held dynamometry is reliable when used to measure knee-extensor strength in frail or elderly persons. However, our results show that, even in these populations, reliability may be compromised by inadequate tester strength.
authors.affiliation: Our Lady's Hospice and Care Services, Harold's Cross, Dublin, Ireland. cstone@olh.ie
authors.forename: Carol A
authors.initials: CA
authors.lastname: Stone
authors.forename: Bríd
authors.initials: B
authors.lastname: Nolan
authors.forename: Peter G
authors.initials: PG
authors.lastname: Lawlor
authors.forename: Rose Anne
authors.initials: RA
authors.lastname: Kenny
mesh_terms: D000058:Accidental Falls; D000328:Adult; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D053580:Muscle Strength / Q000502:physiology*; D053581:Muscle Strength Dynamometer; D009369:Neoplasms / Q000503:physiopathology*; D015588:Observer Variation; D010166:Palliative Care; D015203:Reproducibility of Results; D012307:Risk Factors