Isokinetic testing of ankle strength in older adults: assessment of inter-rater reliability and stability of strength over six months

Arch Phys Med Rehabil. 1994 Nov;75(11):1213-6. doi: 10.1016/0003-9993(94)90007-8.


The study purposes were (1) to estimate the inter-rater reliability of isokinetic strength tests at the ankle in older adults (test-retest interval of three to 7 days), and to determine whether more experienced examiners were more reliable; and (2) to estimate 6 month stability of strength tests. Inter-rater reliability was high for plantar flexion and dorsiflexion tests where average strength was more than about 10 Newton-meters (Nm) (Pearson R = 0.87-0.95). When average strength was less than 10Nm, reliability was less (R = 0.42-0.75). Experienced examiners (physical therapists) and less experienced examiners (research assistants) were equally reliable. Variability in strength over 6 months was no greater than variability over a few days. We conclude that isokinetic tests of ankle strength in older adults are highly reliable and stable when examiners are adequately trained and subjects maintain usual physical activity levels.

Publication types

  • Clinical Trial
  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Aged
  • Aging / physiology*
  • Ankle Joint / physiology*
  • Female
  • Humans
  • Male
  • Muscle Contraction / physiology*
  • Observer Variation
  • Reproducibility of Results