Physiological responses of wheelchair athletes at percentages of top speed

OBJECTIVE: Wheelchair athletes often select a percentage of their top speed (%TS) to determine training intensity. The aim of the study was to determine whether choosing a %TS corresponds to the physiological concept of relative exercise intensity (% peak oxygen uptake: %VO2 peak) and to examine selected physiological and metabolic responses of a group of wheelchair athletes to 60 minutes' exercise at 80% TS. METHODS: 12 male wheelchair athletes (10 paraplegics and two tetraplegics) performed a series of tests on a motorised treadmill adapted for wheelchairs. The tests, which were undertaken on separate occasions, included the determination of VO2 peak, the determination of oxygen cost at a range of submaximal wheelchair propulsion speeds, and a 60 min exercise test at 80% TS. RESULTS: Wheelchair propulsion speeds equivalent to 60%, 70%, 80%, and 90% of each subject's TS were found to equate to 48.3 (SD13.8)%, 60.0(11.1)%, 70.6(9.8)%, and 82.7(9.6)% of VO2 peak, with a wide variation in the relative exercise intensities evident at each %TS. During the 1 h exercise test at 80% TS the physiological and metabolic responses measured were indicative of steady state exercise, with no signs of fatigue evident. CONCLUSIONS: The results of this study suggest that selecting a %TS is not an appropriate way of selecting a common relative exercise intensity. There may also be a need for the current training practises of some wheelchair road racers to be modified.