Neuromuscular and Perceptual Responses to Sub-Maximal Eccentric Cycling.

Pierre Clos,Davy Laroche,Paul J Stapley,Romuald Lepers

doi:10.3389/fphys.2019.00354

Abstract

ObjectiveEccentric (ECC) cycle-ergometers have recently become commercially-available, offering a novel method for rehabilitation training. Many studies have reported that ECC cycling enables the development of higher levels of muscular force at lower cardiorespiratory and metabolic loads, leading to greater force enhancements after a training period. However, fewer studies have focused on the specific perceptual and neuromuscular changes. As the two latter aspects are of major interest in clinical settings, this review aimed to present an overview of the current literature centered on the neuromuscular and perceptual responses to submaximal ECC cycling in comparison to concentric (CON) cycling.DesignNarrative review of the literature.ResultsAt a given mechanical workload, muscle activation is lower in ECC than in CON while the characteristics of the musculo-articular system (i.e., muscle-tendon unit, fascicle, and tendinous tissue length) are quite similar. At a given heart rate or oxygen consumption, ECC cycling training results in greater muscular hypertrophy and strength gains than CON cycling. On the contrary, CON cycling training seems to enhance more markers of muscle aerobic metabolism than ECC cycling performed at the same heart rate intensity. Data concerning perceptual responses, and neuromuscular mechanisms leading to a lower muscle activation (i.e., neural commands from cortex to muscular system) at a given mechanical workload are scarce.ConclusionEven though ECC cycling appears to be a very useful tool for rehabilitation purposes the perceptual and neural commands from cortex to muscular system during exercise need to be further studied.

Highlights

Traditional rehabilitation programs have mainly comprised aerobic submaximal exercise
This study described the electromyographic activity (EMG) of upper body muscles during the two activities, and reported three-times more important integrated EMG from the biceps brachii muscle during ECC cycling compared to CON cycling at the same metabolic load, even though this muscle was not directly involved in the pedaling action
We found that acute ECC cycling differs from CON cycling by inducing lower leg muscle activation at a given mechanical workload, a larger subsequent muscle fatigue, different perceptual responses, and delayed onset of muscle soreness

Summary

Introduction

Traditional rehabilitation programs have mainly comprised aerobic submaximal exercise (e.g., walking on a treadmill, concentric ergocycles, etc.). Stationary cycling is often used as it enables activities to be performed at very low intensities, isolating the mode of muscle contraction to a purely concentric (CON) one. Neuromuscular Responses to Eccentric Cycling in order to generate a force, while eccentric (ECC) contractions are an active lengthening of the muscle (e.g., walking downhill). It is admitted that ECC training can be performed safely with limited muscle damage by increasing the exercise intensity very progressively and keeping it submaximal (LaStayo et al, 2013; Lovering and Brooks, 2013; Hoppeler, 2016). The recent development of commercially available ECC cycle-ergometers has enabled new approaches to rehabilitation methods

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