Effets d'un entraînement en endurance sur des patients atteints de la maladie de McArdle

Abstract

Objectives. – This study assesses on patients with myophosphorylase deficiency (McArdle’s disease) the effects of a moderate aerobic training program (8 weeks, 3 sessions of 45 minutes per week at 60–70% of maximal heart rate) on the physiological response during exercise. Methods. – The cardiorespiratory, electromyographic (EMG) and metabolic responses are evaluated on four patients before and after training to an acute exercise (1 h) on an ergometric bicycle (20–35 Watts) followed by 30 minutes recovery. Results. – Before training, the EMG activity is very high during the first ten minutes of exercise while oxygen uptake (VO 2) remains stable over the 60 minutes of exercise. The heart rate (FC) and the rate of perceived exertion (RPE) are markedly increased. Patients highly use circulatory glucose and free fatty acids for oxidation. During exercise, the 8-week training program reduces EMG activity, FC, RPE and the time of second-wind apparition whereas it has any effect on VO 2. At the end of exercise recovery, patients use more circulatory glucose and product lactate; moreover, their respiratory exchange ratio is increased. Conclusion. - Patients with McArdle disease show an exacerbation of cardiorespiratory, electromyographic and metabolic responses to exercise. A moderate aerobic training program induces muscle, cardiac and metabolic adaptations to physical strain and improves the tolerance of the patients to the physical exercise.