RESPONSES OF SUBJECTS WITH SPINAL-CORD INJURIES TO MAXIMAL WHEELCHAIREXERCISE - COMPARISON OF DISCONTINUOUS AND CONTINUOUS PROTOCOLS

Six male subjects with spinal cord injuries (SCI) participated in this investigation to compare peak values of oxygen uptake (VO2), heart ra te (f(c)), ventilation (V(E)), respiratory exchange ratio (R) and powe r output (W) obtained using a discontinuous (DP) and a continuous jump max protocol (JMP) in a maximal wheelchair exercise test on a treadmi ll. The W increments were achieved by imposing an extra mass upon the wheelchair through a pulley system. The DP involved exercise periods o f 3 min separated by 2-min intervals at relative rest. Increments in W consisted of 0.10 or 0.15 W.kg-1 total mass. During the rest interval s no mass was imposed on the wheelchair. The JMP involved an increase in W each minute. Increments and velocity in the JMP were the same as during the exercise periods for DP. Mean peak values for W [99.5 (SD 1 3.6) W], VO2 [2.13 (SD 0.27) 1.min-1, standard temperature and pressur e, dry], R [1.25 (SD 0.16)] and V(E) [82.8 (SD 11.2) 1.min-1, body tem perature and pressure, saturated] in DP were not different from values observed for W [103.5 (SD 13. 1)], VO2 [2.18 (SD 0.31) 1.min-1], R [1 .17 (SD 0.16)] and V(E) [78.9 (SD 16.0) 1.min-1] in the JMP. The only significant difference was observed for f(c): 198 (SD 11) beats.min-1 in DP and 187 (SD 11) beats.min-1 in JMP. The higher values for f(c) e licited using DP have been discussed. It was concluded that both a DP and a JMP seem to be equally appropriate in determining peak VO2 and p eak W in SCI persons. In terms of time saving, JMP would seem to be a more favourable protocol.