RELATIVE CHANGES IN BLOOD-FLOW WITH FUNCTIONAL ELECTRICAL-STIMULATIONDURING EXERCISE OF THE PARALYZED LOWER-LIMBS

Eight spinal cord injured (SCI) patients performed three sets of exerc ise with two conditions, 60% and 80% of VO2peak, With an arm crank erg ometer. Functional neuromuscular stimulation was used to induce static leg contractions in two of the above sets of exercise. The three exer cise sets were performed with no functional neuromuscular stimulation (NOS); with functional neuromuscular stimulation at 40 milliamperes; a nd with functional neuromuscular stimulation at 80 milliamperes (HIS). The lower limb blood flow was estimated by a photoelectric plethysmog raph. Results showed that the lower limb blood flow was consistently r educed across both functional neuromuscular stimulation levels (17.4% from NOS to LOS; 13.8% from LOS to HIS; and 28.8% from NOS to HIS), an d work loads (15.3% from rest to 60% VO2peak; 38.0% from 60% VO2peak t o 80% VO2peak; and 47.5% from rest to 80% VO2peak) Rate-pressure produ ct was decreased by 8.3% between NOS and HIS at 60% VO2peak (15.7 +/- 3.4 to 14.4 +/- 3.8), by 6.8% between NOS and HIS at 80% VO2peak (18.9 +/- 53 to 17.6 +/- 4.8), and by 12.4% between LOS and HIS at 80% VO2p eak (2.01 +/- 6.7 to 17.6 +/- 4.8). These data indicate that in SCI (a ) functional neuromuscular stimulation-induced contractions of the low er limb muscles can increase blood flow and thus reduce venous blood p ooling in the paralyzed muscles, and (b) such improvements are associa ted with a reduced rate pressure product. In practical terms, this rep resents a potential enhancement of cardiovascular training responses, and thus health status, over that gained from conventional arm exercis es. It has also been suggested that functional neuromuscular stimulati on may provide a more 'natural' means of ameliorating blood pooling, s ince the active contraction of the paralyzed muscles may also enhance their integrity.