Functional tests in elderly osteoarthritic subjects: variability of performance.

The purpose of this study was to evaluate the variability of performance of timed walking and sit-to-stand tests in elderly osteoarthritic subjects. Thirteen elderly subjects were asked to walk, as quickly as possible, along a flat corridor a distance of ten metres. The time and number of strides taken were recorded. Fourteen subjects were asked to perform a series of five sit-to-stand movements as quickly as possible from a plinth 48 cm high. Subjects performed three repeats of each test procedure with a two-minute rest period between each. This was undertaken on three separate occasions within a one-week period. A significant difference (p < 0.05) was observed for the time taken to complete the ten metres over the nine tests, but no significant difference was observed in the number of strides taken. The mean coefficient of variation for time taken was 7.3 per cent, which compares favourably with normal biological systems (1). No significant difference was observed for the time taken during the sit-to-stand test over the nine tests. These simple tests of functional ability may be confidently applied as sequential measures in the clinical setting.