BLOOD REDISTRIBUTION AND CIRCULATORY RESPONSES TO SUBMAXIMAL ARM EXERCISE IN PERSONS WITH SPINAL-CORD INJURY

The purpose of this study was to evaluate responses to submaximal arm exercise (20%, 40%, and 60% of peak power output) using four condition s to support the circulatory redistribution in persons with spinal cor d injury (SCI). Five males with tetraplegia (TP) and four males with p araplegia (PR) exercised 1) sitting, 2) supine, and 3) sitting with th e addition of a) an anti-gravity suit (anti-G), b) elastic stockings a nd abdominal binder, and c) functional electrical stimulation of the l eg muscles. Compared to sitting, the following significant changes wer e observed: in the supine position, heart rate (HR) decreased (PR: 104 vs 118 b/min, TP: 76 vs 92 b/min) and stroke volume (SV) increased (P R: 132 vs 116 ml, TP: 96 vs 83 ml), The anti-G suit induced a decrease in heart rate (PR: 104 vs 118 b/min, TP: 87 vs 92 b/min) and a decrea se in oxygen uptake (VO2) in PR. Stockings only affected TP, i.e. a de crease in heart rate with 5 b/min and an increase in stroke volume wit h 13 ml/beat, Functional electrical stimulation produced an increase i n VO2 (PR: 1.00 vs 0.95 l/min, TP: 0.68 vs 0.53 l/min) and a rise in s troke volume in TP. Results indicate that the methods employed to supp ort the circulatory redistribution have different working mechanisms a nd, in addition, that the effects are different for TP and PR probably because of differences in active muscle mass, sympathetic impairment and blood pressure values.