Assessment of fatigability of older women during sit-to-stand performance

Fatigability of older adults is relevant with regard to physical performance, falls and physical activity. Objective and inexpensive assessment tools for testing fatigability in the persons' home environment are not available. The aim of this study was to develop a protocol to objectively measure fatigability during repeated sit-to-stand performance in older persons. Decrease of maximum velocity of performance during repeated sit-to-stand transfers and the number of repetition when achieving a 10, 15, and 20 % fatigue threshold were measured in 49 community-dwelling older women using a linear encoder. Mean maximum velocity of the sit-to-stand performance was 1.12 m/s (SD 0.17 m/s) with an estimated change of velocity per repetition of -0.0037 m/s (95 % CI -0.0039 to -0.0035) during the test. The mean number of repetitions representing 10, 15, and 20 % fatigue threshold was 8.1, 13.8, and 21, respectively. This simple test protocol provides objective information about the decrease of performance of a daily task in older adults. Fatigability of the sit-to-stand performance can be measured objectively by measuring the decrease of maximum velocity of consecutive repetitions and the repetition number achieving a 20 % fatigue threshold.