| Abstrakt: |
Eight spinal cord injured (SCI) patients performed three sets of exercise with two conditions, 60% and 80% of VO2peak,with an arm crank ergometer. Functional neuromus-cular stimulation was used to induce static leg contractions in two of the above sets of exercise. The three exercise sets were performed with no functional neuromuscular stimulation (NOS); with functional neuromuscular stimulation at 40 milliamperes; and with functional neuromuscular stimulation at 80 milliamperes (HIS). The lower limb blood flow was estimated by a photoelectric plethysmograph. Results showed that the lower limb blood flow was consistently reduced 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), and work loads (15.3% from rest to 60% VO2peak,38.0% from 60% VO2peak,to 80% VO2peak,and 47.5% from rest to 80% VO2peak,). Rate-pressure product 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% VO2peak(20.1 ± 6.7 to 17.6 ± 4.8). These data indicate that in SCI (a) functional neuromuscular stimulation-induced contractions of the lower limb muscles can increase blood flow and thus reduce venous blood pooling in the paralyzed muscles, and (b) such improvements are associated with a reduced rate pressure product. In practical terms, this represents a potential enhancement of cardiovascular training responses, and thus health status, over that gained from conventional arm exercises. It has also been suggested that functional neuromuscular stimulation may provide a more 'natural' means of ameliorating blood pooling, since the active contraction of the paralyzed muscles may also enhance their integrity. |
