Effects of Eccentric Pedaling at Different Rates on Neuromuscular Function

Overview

The recent appearance of ergocycles that can be used for eccentric pedaling (Cyclus type) has aroused a growing interest in the field of rehabilitation. The mechanical, metabolic, and cardiorespiratory characteristics of eccentric exercises make them an exercise of choice when the goal is to improve locomotor muscle function and exercise capacity. Despite its potential advantages, the optimal modalities of eccentric pedaling, in particular the choice of pedaling frequency, are still poorly understood, especially its effects on the neuromuscular system. Indeed, most training protocols impose a fixed pedaling power but with highly variable pedaling rates, ranging from 15 to 60 rpm (Besson et al., 2013; MacMillan et al., 2017). For a given pedaling power level (P), the choice of pedaling frequency (F) directly impacts the force torque (C) and thus the force applied to the pedals, since power is equal to the product of pedaling frequency and force torque (P = F.C). For frequencies varying from 15 to 60 rpm, the level of muscular tension during pedaling therefore varies from single to quadruple. These very large variations in force can influence the neuromuscular adaptations induced during a prolonged training period. For example, the use of low pedaling frequencies corresponding to high muscle tension could favor peripheral muscular adaptations (e.g. contractility) whereas higher pedaling frequencies could favor central (i.e. nervous) adaptations. A better understanding of the neuromuscular adaptations induced by a period of eccentric pedaling at different cadences will allow for a more precise definition of training protocols for populations likely to undergo this type of training (e.g. elderly people, patients with heart failure).