Validité d'un modèle dans l'appréciation partielle de la dépense énergétique d'une épreuve de marathon

The metabolic model of Péronnet et al. (1983) has been compared to experimental data collected on 36 men submitted to an exhaustive exercise on bicycle ergometer and to a marathon race (42.2 km). The predicted values of the Péronnet model have been compared to an extension of the model modified by the thermal estimates (model of Snoeck). The calculated VO 2 max recorded from the performance time of the marathon race (Péronnet) was not statistically different (1.7 ml/kg.min) from the values obtained from the laboratory test. An underestimation of 3.1% of body fat has been observed in the model of Péronnet as compared to the skinfold method. However, a high statistical correlation (r=0.814) was obtained between the skinfold method (Durnin) and the estimation from the wrist circumference, the height and the weight (Péronnet). The weight deficit has been overestimated in the model of Péronnet when compared to weighing measurements and to the corrected model of Snoeck. The discrepancy of the former model to the observed values seems to be due to an overestimation of the convective heat exchange, the evaporative heat loss and the sweat rate. Moreover, there is a 2.4% lack in the estimation of the total energy cost in the model of Péronnet which does not take the aerodynamic drag into account (model of Snoeck). Eventually, there is a satisfactory validation of the changes of glycemia between the model of Péronnet and the measured level of blood glucose during the marathon event, the mean differences (rest-post-exercise) being 0.09 mmoles/1 and −0.31 mmoles/1 respectively (no statistical difference).