Validity and usefulness of hand-held dynamometry for measuring muscle strength in community-dwelling older persons.

The aim was to determine the validity and usefulness of hand-held dynamometry for measuring muscle strength in independent community-dwelling older persons. Cross-sectional study was performed in 281 subjects aged over 65, mean age of 74.3 years. The strength of six muscle groups was measured in three consecutive attempts using JAMAR hand-held dynamometers. Individual values, maximums and means, intra- and inter-individual variability, test-retest reliability and concurrent validity with functional tests are described. The main results were: strength increased with each attempt for all muscle groups, suggesting technique learning, except for pinch and grip, suggesting muscle fatigability. Relative intra- and inter-individual variability was higher in women; it was lower for the pinch and grip strength. Test-retest reliability was very good and concurrent validity with functional tests was good. We conclude that hand-held dynamometry is valid and useful for determining functionality. It is recommended to perform three attempts for all strength measurements, except for pinch and grip, in which one is sufficient.