Amputation: energy cost of ambulation.

A mobile instrument system was used to measure energy consumption by indirect calorimetry at rest and during ambulation in 25 unimpaired subjects, 6 unilateral below-knee (BK) amputee patients, 6 unilateral above-knee (AK) amputee patients and 4 bilateral AK amputee patients. To prevent the introduction of gait difficulties among the impaired subjects, each subject was permitted to walk at his own comfortable speed. Since speed thus varied among subjects, ambulation data were expressed in units of energy per foot traveled. Statistical analyses of the mean oxygen costs indicated several significant differences among the groups. In comparison to unimpaired subjects, the mean oxygen consumption was 9% higher in unilateral BK amputee patients, 49% higher in unilateral AK amputee patients and 280% higher in bilateral AK amputee patients.