Mechanical factors of the energy cost in three human locomotions

Objectives - The aim of this review is to detail the mechanical factors of the energy cost in three human locomotions, which are swimming, cycling and running. Topics - The hydro- or aero-dynamic drags (i.e., pressure and friction drags) are the most important external resistances, encountered by the locomotion in swimming and cycling. The influence of the gradient of the slope, the body mass, the additional weights, the velocity, the cycle frequency and length, the mechanical power and the stretch-shortening-cycle on the energy cost is also reported. Future prospects - The measure of the gas exchanges in situ during the training sessions with portable devices could be linked to the quantification of the mechanical energy and would make possible the evaluation of the muscular efficiency of athletes in their real activity and allowing also an objective measurement of their technical ability in the locomotion. (C) 2002 Editions scientifiques et medicales Elsevier SAS.