Objective: To compare hand-held isometric muscle strength measurement to an isokinetic muscle strength measurement in a healthy elderly population.
Design: Cross-sectional survey.
Setting: Retirement community in Southeastern Arizona.
Participants: Thirty-two volunteers (16 men and 16 women) age 60 and over (mean age 70.3 years) who were free of musculoskeletal problems and did not have significant health problems.
Measurements: Isometric muscle strength was determined using a hand-held isometric strength device (Penny and Giles) for elbow flexion and extension and knee flexion and extension. Isokinetic muscle strength (average peak torque and average work per repetition) was measured on the same individuals using a Lido isokinetic dynamometer.
Results: Correlations between the strength measurement techniques were generally favorable with the lowest correlation being .72, (95 percent confidence interval .50-.86) and the highest being .85, (95 percent confidence interval .72-.93). However, there was substantial variability of hand-held strength reading at some levels of isokinetic strength.
Conclusions: Hand-held dynamometry for strength measurement correlates strongly with measurement of strength using isokinetic dynamometry. Despite these high correlations, there is remaining variability of hand-held muscle strength readings when compared with isokinetic strength measurement at some levels of isokinetic muscle strength. Modification of the testing methodology or instrumentation used in this study is needed to improve the consistency of these measurements.