Reproducibility of upper leg EMG frequency content during cycling

Abstract

Reproducibility of frequency content from surface electromyography (sEMG) signals has not been assessed and it is unknown if incremental load testing design could affect sEMG in cycling. The goals of this study were to assess the reproducibility of measures from sEMG frequency content between sessions and to compare these frequency components between a ramp and a step incremental cycling test. Eighteen cyclists performed four incremental load cycling tests to exhaustion. Two tests were performed using a step increment (load started at 100 W for 3 min followed by increments of 30 W every 3 min) and two were performed using a ramp increment (load started at 100 W for 1 min followed by increments of 30 W·min). sEMG was monitored bilaterally for the rectus femoris and vastus lateralis throughout the tests and converted into overall activation (whole signal bandwidth), high- and low-frequency contents. The reproducibility of the frequency content ranged from none to strong (ICC = 0.07-0.90). Vastus lateralis activation was larger at the step compared to the ramp test (P < 0.01), without differences for rectus femoris (P = 0.22-0.91) and for the high-frequency (P = 0.28-0.95) and low-frequency contents (P = 0.13-0.94). sEMG from vastus lateralis and rectus femoris presented none to strong reproducibility. Vastus lateralis is more activated in step test design.

The repeatability of neuromuscular activation strategies recorded in recreationally active individuals during cycling

“…Several studies have examined the repeatability of sEMG bursts within individuals cycling under the same conditions across multiple days. These studies have demonstrated high reproducibility of the magnitude components of the signals (Laplaud et al 2006 ; MacDonald et al 2008 ; Travis et al 2011 ; Bini et al 2017 ), with one finding high reproducibility of the temporal components (Jobson et al 2013 ). These findings suggest that the same muscle activation patterns are consistently used during cycling, indicating good potential for these measures to be used for monitoring changes in clinical and sports training settings.…”

Rate of change in longitudinal EMG indicates time course of an individual's neuromuscular adaptation in resistance-based muscle training

“…Commonly used biopotential measurement systems such as surface electromyograms (EMG) have demonstrated use in these findings, specifically in identifying the patterns of contractile amplitudes and frequencies during a fatiguing exercise (1)(2)(3)(4)(5)(6). For example, fatiguing muscles show an increase in EMG contractile amplitude that correlates to the number of recruited motor neurons, as well as a low-frequency shift in the raw EMG signal (7)(8)(9)(10). These frequency-based analyses are a popular strategy to measure the presence of fatigue and adaptation in short-term applications such as on a set-to-set basis (2,11,12).…”