Use of accelerometry to quantify the physical activity level of the elderly

This study investigated the reliability and validity of using an accelerometry system to quantify the physical activity level of Chinese elderly subjects. Thirty-eight volunteers wore an accelerometer for 3 days. Test-retest reliability, the sensitivity of the measurements, and the correlation between the results and the results of a commonly used physical activity questionnaire were measured. The accelerometry system was found to be reliable (intraclass correlation coefficient, 0.978). The system was able to differentiate young adults and active elderly from sedentary elderly subjects (p<0.001).The results showed a moderate but significant correlation with scores on the questionnaire (r=0.830; p<0.001). The accelerometry system can be used as an objective tool to quantify the physical activity level of the elderly, specifically Chinese subjects.