RESPONSES OF OXYGEN CONSUMPTION, HEART RATE AND PERCEIVED EXERTION TO CRUTCH WALKING: A COMPARISON BE TWEEN PAR APLEGIC AND ABLE-BODIED SUBJECTS

In this study, 10 normal volunteers and 5 sports-trained paraplegics with lesions between T6 and L2 were studied whilst walking with axillary crutches and knee-anlde-foot orthoses. All subjects walked at their preferred speed on a figureof- eight track. Normal subjects also walked at slower and faster speeds. Oxygen consumption, heart rate and rating of perceived exertion were measured. In normal subjects, stable heart rates (±2 beats/min) were rapidly reached within two minutes at all three speeds. In paraplegics, the heart rate responses were more variable. The heart rate response in lumbar level paraplegics resembled normal subjects. Thoracic level paraplegics rarely showed stable heart rates during walking and in some instances, the rate rose progressively up to values of about 180 beats/min. In normal subjects walking in knee-ankle-foot orthoses, there was no significant difference of energy cost and physiological cost index between preferred and fast speeds. The preferred and fast speeds were also more efficient for crutch walling. There was a significant correlation (p<0.01) between energy cost and physiological cost index (r=0.65). Both energy cost and physiological cost index are standardized by dividing by speed this has not been done for perceived exertion. The results show a greater load on the cardio-respiratory system in paraplegics. This may be partly explained by decreased venous return due to impaired muscle function in the lower limb and relatively low frequency of stepping.