Cardiovascular responses during nonweight-bearing and touchdown ambulation

The purpose of this study was to compare selected physiological responses of nonweight-bearing (NWB) and touchdown (TD) ambulation using axillary crutches. Ten subjects walked at a constant rate for five minutes at a mean velocity of 48.42 m/min for NWB and 48.95 m/min for TD. Weight bearing was controlled with an augmented sensory feedback device. Heart rate, blood pressure, oxygen consumption, and perceived exertion were measured. Myocardial oxygen consumption was estimated from heart rate alone and from the double product of systolic blood pressure and heart rate. Oxygen consumption and systolic blood pressure were similar for NWB and TD. Heart rate and myocardial oxygen consumption were significantly higher during NWB, and this was attributed to greater upper and lower extremity isometric exercise required for NWB versus TD ambulation. Physiologically, TD may be preferable to NWB for persons who are deconditioned or limited in their exercise capacity.