Abstract
[Purpose] The purpose of this research was to study the test-retest reliability of isometric knee extension muscle strength measurement using a hand-held dynamometer (HHD) with a belt, with healthy elderly people living in the community as subjects. [Subjects] The subjects were healthy elderly people living in the community, with an average age of 70.5 years, and measurements were made of the leg on the side that was used to kick a ball. [Method] The subjects sat on a mat table, and isometric knee extension muscle strength measurements using a HHD with a belt were conducted twice, at an interval of 30 seconds, with a knee flexion angle of 90 degrees. The measurement values were classified according to the gender of the subjects, and by age group 65-69 years, 70-74 years, and 75 years and above, and studied. Test-retest reliability was studied using the intraclass correlation coefficient (ICC) and checks of the differentials. [Results] The ICC(1,1) between the first and second measurements ranged from 0.85 to 0.92. Apart from the group of men aged 75 years and above, the second measurement values were higher than those of the first. [Conclusion] Test-retest reliability of isometric knee extension muscle strength measurement using a HHD with a belt was high in healthy elderly persons. However, measuring only once, or measuring twice and taking the average was considered inappropriate, since there is the possibility that the values in such cases would be lower than the actual muscle strength.
