Comparison between eccentric-only and coupled concentric-eccentric contractions for neuromuscular fatigue and muscle damage
Abstract
Purpose: Eccentric contractions induce muscle damage, but less is known about the effects of preceding concentric contractions to eccentric contractions on muscle damage. We compared eccentric-only (ECC) and coupled concentric and eccentric contractions (CON-ECC) of the knee extensors for parameters of neuromuscular fatigue and muscle damage. Methods: Twenty participants (age, 19-36 yr) were randomly placed into an ECC or a CON-ECC group (n = 10 per group), without significant (P > 0.06) differences in baseline neuromuscular variables between groups. The ECC group performed six sets of eight ECC at 80 % of ECC one-repetition maximum (1-RMecc), whereas the CON-ECC group performed six sets of eight alternating concentric (CON) and ECC (16 contractions per set) at 80% of CON 1-RM and 1-RMecc, respectively. Maximal voluntary isometric contraction force, rate of force development, resting twitch force, maximal M-wave (MMAX), voluntary activation, motor evoked potentials, corticospinal silent period, short interval intracortical inhibition, and muscle soreness were measured before, immediately after, and 1-3 d after exercise. Results: No significant (P ≥ 0.09) differences between ECC and CON-ECC were observed for changes in any variables after exercise. However, maximal voluntary isometric contraction force decreased immediately after exercise (ECC: -20.7 % ± 12.8 %, CON-ECC: -23.6 % ± 23.3 %) and was still reduced 3 d after exercise (ECC: -13.6 % ± 13.4 %, CON-ECC: -3.3 % ± 21.2 %). Rate of force development at 0 - 30 ms reduced immediately after exercise (ECC: -38.3 % ± 33.9 %, CON-ECC: -30.7 % ± 38.3 %). Voluntary activation, resting twitch force, and motor evoked potential/MMAX decreased and corticospinal silent period increased after exercise (all P ≤ 0.03), but short interval intracortical inhibition and MMAX did not change. Muscle soreness developed (P < 0.001) similarly for both groups (peak, 38.5 ± 29.5 mm). Conclusions: CON-ECC did not exacerbate neuromuscular fatigue and muscle damage when compared with ECC, despite twice as many contractions performed. Thus, eccentric contractions (n = 48 in both groups) seemed to mainly mediate the neuromuscular responses observed.
Keywords
maximal voluntary contarction, rate of force development, peripheral twitch force, voluntary activation, corticospinal excitability, short interval intracortical inhibition
Document Type
Journal Article
Date of Publication
10-1-2022
Volume
54
Issue
10
PubMed ID
36106831
Publication Title
Medicine and science in sports and exercise
Publisher
Wolters Kluwer
School
School of Medical and Health Sciences / Centre for Human Performance
RAS ID
46952
Copyright
subscription content
First Page
1635
Last Page
1646
Comments
Ruas, C. V., Latella, C., Taylor, J. L., Haff, G. G., & Nosaka, K. (2022). Comparison between eccentric-only and coupled concentric-eccentric contractions for neuromuscular fatigue and muscle damage. Medicine & Science in Sports & Exercise, 54(10), 1635-1646. https://doi.org/10.1249/MSS.0000000000002959