The aim of the study is to compare two methods of exercise training: alternate load versus constant load realized at moderate or high intensities, in order to define the interests and the limits of each one of these two methods. The finality is to make possible to the expert to choose what exercise training induces the best results quickly and to make its choice according to the therapeutic objectives which it lays down.We also evaluate the effects of these exercises training on the vagal response and the bronchial tone of the asthmatics. From a clinical point of view, a close attention will be paid to the effects of these exercises training on the control of asthma and the quality of life of the subjects