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.

Energy expenditure of ambulation in patients with above-knee amputations.

Oxygen consumption during ambulation was measured in nine middle-aged or elderly subjects having above-knee amputations, in an effort to determine the mode of ambulation and prosthetic prescription requiring the least energy expenditure. Studies revealed that crutch walking and prosthetic ambulation require the same energy expenditure; that there is no significant difference between the energy requirements of ambulating with knee locked or unlocked; and that 65 percent more energy is required at approximately one-half the normal speed of ambulation for above-knee amputees as compared to normal persons.