Leg Muscle Activity and Perception of Effort before and after Four Short Sessions of Submaximal Eccentric Cycling

Romuald Lepers,Pierre Clos

doi:10.3390/ijerph17217702

Abstract

Background: This study tested muscle activity (EMG) and perception of effort in eccentric (ECC) and concentric (CON) cycling before and after four sessions of both. Methods: Twelve volunteers naïve to ECC cycling attended the laboratory six times. On day 1, they performed a CON cycling peak power output (PPO) test. They then carried-out four sessions comprising two sets of 1 to 1.5-min cycling bouts at 5 intensities (30, 45, 60, 75, and 90% PPO) in ECC and CON cycling. On day 2 and day 6 (two weeks apart), EMG root mean square of the vastus lateralis (VL), rectus femoris (RF), biceps femoris (BF), and soleus (SOL) muscles, was averaged from 15 to 30 s within each 1-min bout and perception of effort was asked after 45 s. Results: Before the four cycling sessions, while VL EMG was lower in ECC than CON cycling, most variables were not different. Afterwards, ECC cycling exhibited lower RF EMG at 75 and 90% PPO (all p < 0.02), lower VL and BF EMG at all exercise intensities (all p < 0.02), and inferior SOL EMG (all p < 0.04) except at 45% PPO (p = 0.07). Perception of effort was lower in ECC cycling at all exercise intensities (all p < 0.03) but 60% PPO (p = 0.11). Conclusions: After four short sessions of ECC cycling, the activity of four leg muscles and perception of effort became lower in ECC than in CON cycling at most of five power outputs, while they were similar before.

Highlights

In contrast to the type of pedaling we all know (i.e., concentric (CON) cycling), eccentric (ECC)cycling makes the muscle lengthen while contracting
The EMG of all leg muscles studied was systematically lower in ECC than CON cycling at the same power output: this was the case for the vastus lateralis muscle (VL) [9,10,11,12], the rectus femoris (RF), and the biceps femoris (BF) muscles [11,12], and for the vastus medialis muscle [12]
We investigated whether four sessions of 10 to 15 min of submaximal ECC cycling would affect the activity of four leg muscles and perception of effort over a range of submaximal exercise intensities

Summary

Introduction

In contrast to the type of pedaling we all know (i.e., concentric (CON) cycling), eccentric (ECC)cycling makes the muscle lengthen while contracting. In Peñailillo et al, (2013), volunteers merely pedaled for 5 min at a power output of 50 W, whereas in Lechauve et al, (2014) they completed 6 sessions lasting 5 to 15 min at an intensity ranging from 50 W to 300 W Despite these differences, the EMG (root mean square, RMS) of all leg muscles studied was systematically lower in ECC than CON cycling at the same power output: this was the case for the vastus lateralis muscle (VL) [9,10,11,12], the rectus femoris (RF), and the biceps femoris (BF) muscles [11,12], and for the vastus medialis muscle [12].

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