Test-retest reliability of lower extremity functional instability measures

Clin J Sport Med. 2000 Oct;10(4):264-8. doi: 10.1097/00042752-200010000-00007.


Objectives: 1) To evaluate the test-retest reliability of lower extremity functional instability measures involving testing situations of varying complexity, and 2) To evaluate the interrelationships among performances observed during these tests and a maximal single-limb forward hop for distance.

Design: A repeated measures design, repeated on two occasions.

Setting: Postural control laboratory.

Participants: Thirty young healthy subjects (23.5 +/- 2.0 years).

Main outcome measures: Subjects performed single-limb standing balance and forward hop tests on two occasions completed within 1 week and at least 24 hours apart. Standing balance was assessed using a force platform and the following four progressively complex test situations: 1) standing on the stable platform with eyes open, 2) standing on a foam mat placed over the platform with eyes open, 3) standing on the stable platform with eyes closed, and 4) standing on the stable platform after landing from a maximal single-limb forward hop.

Results and conclusions: Intraclass correlation coefficients were moderate to excellent (0.41 to 0.91) suggesting that the standing balance tests are appropriate for distinguishing among group performances. Standard errors of measurement and associated 95% confidence intervals suggested that a change in an individual's standing balance performance of approximately 10-30% would be necessary in order to confidently state that a true change had occurred. Stronger relationships were observed between hop distance and standing balance tests performed with eyes closed (r = -0.63, p < 0.001) and after landing from a maximal hop (r = -0.53, p = 0.003), suggesting that tests that challenge postural control to a greater extent are more representative of functional performance.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Exercise Test / methods*
  • Female
  • Humans
  • Leg / physiology*
  • Male
  • Postural Balance / physiology*
  • Posture / physiology
  • Reproducibility of Results
  • Visual Perception / physiology