Anaerobic fitness in children with asthma:: Adaptation to maximal intermittent short exercise

Nineteen asthmatic boys (aged 13.4 years, 25-75 percentile: 11.5-15.1 years) performed short bouts of maximal exercise (force-velocity test) to test their anaerobic fitness and tolerance of maximal anaerobic exercise. Fourteen healthy boys (aged 13.9 years, 25-75 percentile: 11.6-15.7 years) matched for anthropometric characteristics including lean body mass (LBM), pubertal stage, and weekly physical activity formed a control group. The maximal anaerobic power (W-ana) was measured during the force-velocity test. The maximal oxygen uptake (V'(O2max)) was assessed during a standard graded exercise test. Pre- and post-exercise pulmonary function was measured by body plethysmography. The asthmatic children exhibited lower W-ana than the control group (8.2 watt kg(-1) LBM, 25-75 percentile: 7.55-10.6 vs. 11.3 watt.kg(-1) LBM, 25-75 percentile: 9.46-14.1; P=0.01). V'(O2max) was also diminished in the asthmatic group (P=0.01). Multiple stepwise regression models revealed that Tanner's score (P < 0.001) and the diagnosis of asthma (P < 0.01) were the best predictors of W-ana. In conclusion, a diminished anaerobic fitness could contribute to the overall exercise limitation in asthmatic children.