Cardiovascular stress of crutch walking.

The cardiovascular (CV) stress of crutch walking was studied in 8 normal subjects ambulating with under arm crutches at 30, 40, 50, 60, 70 and 80m.min-1 on the level, at 40 and 60m.min-1 up a 5% grade, and climbing stairs at the rate of 16 and 24 stairs/min. A progressive exercise stress test was performed on each subject using a hand-cranked bicycle ergometer for the upper extremities and treadmill for the lower extremities. Heart rates (HR) were significantly higher than in normal walking at equivalent O2 uptake (VO2) levels. The HR slope versus VO2 for each crutching activity was similar to that obtained for the upper extremities stress test. This suggests that crutching acts as an upper extremity activity in terms of CV stress. Using the ventilatory equivalent (VE/(VO2), the estimated anaerobic threshold point started at 60m.min-1 for level crutching. It was estimated that a subject with a pulse rate limit of 140bpm could either crutch at 60m.min-1 (2.2mi.hr-1) or run at 134m.min-1 (5mi.hr-1).