Economy of mobility in older adults.

A decline in economy of mobility indicates that more physical work is required for a task (ie., walking) and may suggest an abnormal gait pattern. A normal gait pattern is essential for maintaining independence in older adults. The purpose of this study was to compare economy of mobility between sedentary older men and women. The subjects were 47 men (mean +/- SD; age = 71 +/- 4 years, weight = 83 +/- 8 kg, height = 175 +/- 7 cm) and 51 women (70 +/- 3 years, 65 +/- 8 kg, 161 +/- 5 cm). Men were significantly (p < 0.05) older, heavier, and taller than women. Maximal oxygen uptake (VO2max) was collected while subjects walked on a treadmill until volitional exhaustion. On a separate day, a submaximal test was performed at one speed requiring approximately 60% of VO2max on a level treadmill for 5 minutes. Men had significantly greater absolute and relative VO2max than women. Men walked at a significantly faster speed (92 +/- 8 vs. 86 +/- 7 m/min) than women during the submaximal test. Economy of mobility was the same for older men and women (0.17 +/- 0.02 ml/kg/m) with differences in walking speed controlled. The results indicate that there is not a gender-specific decrement in economy of mobility with aging.