ABSTRACT
PURPOSE: We tested the hypothesis that, in eight participants (seven males, one female; 46.5 +/- 8.3 years) with spinal-cord injury (complete lesions, T7-L1), the effects of exercise training on pulmonary O2 uptake (VO2) on- and off-kinetics would appear early in this pilot study. METHODS: The subjects underwent the wheelchair-training program (3 day/w, 30 min/day, and 50% HRreserve), and were evaluated before training ("time 0", T0), and after 7 (T7), 15 (T15), 30 (T30), and 60 (T60) days of training. Breath-by-breath peak VO2 was determined during the incremental exercise until their exhaustion. At another day following the incremental exercise, the subjects performed three repetitions of a constant exercise at 50% peak VO2 workload so that VO2 could be determined for both on- and off-kinetics. RESULTS AND CONCLUSION: Peak VO2 showed a tendency to increase with training; the increases became significant at T30. The time constants (tau 2) during "phase II" of the VO2 on-kinetics were 62.4 +/- 13.0 (s) (T0), 51.2 +/- 8.7 (T7), 46.1 +/- 7.4 (T15), 45.0 +/- 7.2 (T30), and 43.4 +/- 6.4 (T60); a significant difference compared to T0 was observed from T7 onward. The same pattern of change as a function of training was described for the VO2 off-kinetics. It is concluded that in SCI participants, the acceleration of VO2 kinetics at the onset of exercise was observed over a short term.
