Predicting oxygen uptake in older adults using lower-limb accelerometer measures

Assessing physical activity in older adults has proven to be difficult but important, because regular participation has a protective and rehabilitative effect against disability and morbidity. Commercially available physical activity monitors measure waist movements and have not been validated for older adults. This study developed a model for establishing prediction equations to estimate older adults physical activity levels based on lower-limb accelerometer measures. Oxygen uptake and lower-limb accelerometer data were simultaneously recorded from treadmill and stair-climbing exercises. The best stepwise regression equations were obtained when accelerometer and weight measures were regressed on oxygen uptake when subjects walked 1, 2, and 3 miles per hour (R = 0.69 with accelerometer on back of the heel) and for accelerometer measures and gender when subjects climbed stairs (R = 0.77 with accelerometer on mid-ankle). These findings illustrate that physical activity can be effectively predicted in older adults from lower-limb accelerometer measurements.