Cardiorespiratory Fitness Evaluation by the Shuttle Test in Asthmatic Subjects During Aerobic Training

The purpose of this study was to assess the validity of the 20-m shuttle test with 1-min stages (20-MST) to estimate maximal oxygen uptake ( V˙o2 max) and its ability to register cardiorespiratory modifications over the course of an individualized aerobic training program for mild to moderately asthmatic children acclimatized to moderate altitude. Forty-eight asthmatic subjects aged 12 to 17 years performed both a maximal incremental exercise test on a cycle ergometer and the 20-MST. Ten of the subjects were then randomly chosen and trained three times per week at their ventilatory threshold (Vth) intensity level for three months. Another group of ten asthmatic subjects served as control subjects. Training intensity was adjusted monthly; heart rate values at Vth were increased by the same proportion as the increase in V˙o2 max as measured by the 20-MST. At the end of training, both groups were again evaluated with the two tests. The Vo, max values by direct measurement and by the 20-MST were not significantly different for the entire population (46.5 ± 1.6 vs 47.2 ± 2.1 ml•min−1•kg−1)· In addition, the two test results were in close agreement (r = 0.84; p