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Eur J Appl Physiol. 2018 Apr;118(4):805-816. doi: 10.1007/s00421-018-3816-0. Epub 2018 Feb 6.

Changes in central and peripheral neuromuscular fatigue indices after concentric versus eccentric contractions of the knee extensors.

Author information

1
Laboratoire "Motricité, Interactions, Performance" (EA4334), Faculté des Sciences du Sport, Université de Nantes, 25 bis Boulevard Guy Mollet-BP 72206, 44 322, Nantes cedex 3, France.
2
Univ Lyon, UJM Saint-Etienne, Laboratoire Interuniversitaire de Biologie de la Motricité, EA 7424, F-42023, Saint-Etienne, France.
3
Centre for Exercise and Sports Science Research, School of Medical and Health Sciences, Edith Cowan University, Joondalup, WA, 6027, Australia.
4
Laboratoire "Motricité, Interactions, Performance" (EA4334), Faculté des Sciences du Sport, Université de Nantes, 25 bis Boulevard Guy Mollet-BP 72206, 44 322, Nantes cedex 3, France. marc.jubeau@univ-nantes.fr.

Abstract

PURPOSE:

To better understand neuromuscular characteristics of eccentric exercise-induced muscle damage, this study compared between concentric (CONC) and eccentric (ECC) exercises of knee extensor muscles, and the first (ECC1) and second bouts of the eccentric exercise (ECC2) for central and peripheral parameters associated with neuromuscular fatigue.

METHODS:

Twelve young men performed three exercise bouts separated by at least 1 week between CONC and ECC1, and 2 weeks between ECC1 and ECC2. In each exercise, maximal voluntary concentric or eccentric contractions of the knee extensors were performed until a reduction in maximal voluntary isometric contraction (MVC) torque of at least 40% MVC was achieved immediately post-exercise. MVC torque, central (voluntary activation and normalised electromyographic activity), and peripheral neuromuscular indices (evoked torque and M-wave amplitude), and muscle soreness were assessed before (PRE), immediately after (POST), 1 h (1H), and 1-4 days after exercise (D1, D2, D3, and D4).

RESULTS:

MVC torque decreased at only POST for CONC (- 52.8%), but remained below the baseline at POST (- 48.6%), 1H (- 34.1%), and D1-D4 (- 34.1 to - 18.2%) after ECC1, and at POST (- 45.2%), 1H (- 24.4%) and D1 (- 13.4%) after ECC2 (p < 0.05). Voluntary activation decreased immediately after ECC1 (- 21.6%) and ECC2 (- 21.1%), but not after CONC. Electrically evoked torques decreased similarly at POST and 1H for the three conditions, but remained below the baseline at D1 only post-ECC1.

CONCLUSION:

These results showed that both central and peripheral factors contributed to the MVC decrease after ECC1 and ECC2, but the decrease was mainly due to peripheral factors after CONC.

KEYWORDS:

Central fatigue; DOMS; EMG; Electrical stimulation; Interpolated twitch technique; Repeated bout effect

PMID:
29411127
DOI:
10.1007/s00421-018-3816-0
[Indexed for MEDLINE]

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