Oxygen consumption of elderly persons with bilateral below knee amputations: ambulation vs wheelchair propulsion

Elderly bilateral below knee (BK) amputees were tested for oxygen consumption (VO2), heart rate (HR) and velocity (V) during ambulation on a 40m walkway and a stationary wheelchair ergometer. Values obtained from amputees were compared to values obtained from a control population of the same age group. On test day 1 bilateral amputees and normal subjects ambulated at their natural pace on a walkway for approximately 5 minutes. On test day 2 each subject propelled a stationary wheelchair ergometer at their natural rate for the same distance that they ambulated. Measurements of VO2 (ml/m/kg), HR (beats/min), and V (m/min) were obtained during both sessions. Results show that the bilateral BK group required significantly more VO2 (ml/m/kg) (123%), had higher HR (26%), and slower V (36%) than the normal group during ambulation. The energy cost in terms of ml/min/kg during ambulation was similar, suggesting that the amputees ambulated at the same power cost as normals but at lower velocities. During wheelchair propulsion the BK group and normal group showed no significant difference in the 2 criteria. Results suggest that wheelchair propulsion is a more energy efficient mode of mobility for elderly bilateral BK amputees than ambulation. Energy cost and heart rate determinations may be valuable in choosing the course of mobility training and recommended activity levels. Cosmetic, psychosocial, and other clinical factors must be considered in prescribing rehabilitation.