Validation of a 30-sec chair-stand test for evaluating lower extremity muscle strength in Japanese elderly adults

Abstract

The ability to rise from a chair is an important task of daily living. Many persons have increasing difficulty with this task as they proceed into the late decades of life. This study examined the validity of a 30-s chair stand (CS-30) test for evaluating the lower extremity muscle strength of 486 Japanese elderly adults (209 men and 277 women, aged 60-87 years). To determine the test-retest reliability of CS-30 performances, 44 elderly men and women underwent CS-30 testing on two occasions, 4-10 days apart. Intraclass correlation coefficient values were r=.84 for men and r=.88 for women, indicating that the CS-30 test has good reproducible reliability. The moderate correlation between CS-30 performance and maximum voluntary isometric contraction force of knee extension was r=.44 for men and r=.52 for women. Regression analysis revealed an age-associated decline in CS-30 performance for men (r=.45, p<0.001) and women (r=.44, p<0.001), but no differences were observed between the gender groups. In both men and women, the CS-30 performance of the 70-74, 75-79, and 80+ yr age groups was significantly lower (p<0.001) than that of the 60-64 yr group. These results suggest that the CS-30 test has a high correlation of test-retest reliability and is a useful method for evaluating the lower extremity muscle strength of Japanese elderly men and women in a field setting.