Power loss is attenuated following a second bout of high-intensity eccentric contractions due to the repeated bout effect's protection of rate of torque and velocity development.
Appl Physiol Nutr Metab
; 46(5): 461-472, 2021 May.
Article
en En
| MEDLINE
| ID: mdl-33125854
ABSTRACT
High-intensity unaccustomed eccentric contractions result in weakness and power loss because of fatigue and muscle damage. Through the repeated bout effect (RBE), adaptations occur, then damage and weakness are attenuated following a subsequent bout. However, it is unclear whether the RBE protects peak power output. We investigated the influence of the RBE on power production and estimated fatigue- and damage-induced neuromuscular impairments following repeated high-intensity eccentric contractions. Twelve healthy adult males performed 5 sets of 30 maximal eccentric elbow flexions and repeated an identical bout 4 weeks later. Recovery was tracked over 7 days following both bouts. Reduced maximum voluntary isometric contraction torque, and increased serum creatine kinase and self-reported soreness indirectly inferred muscle damage. Peak isotonic power, time-dependent measures - rate of velocity development (RVD) and rate of torque development (RTD) - and several electrophysiological indices of neuromuscular function were assessed. The RBE protected peak power, with a protective index of 66% 24 h after the second eccentric exercise bout. The protection of power also related to preserved RVD (R2 = 0.61, P < 0.01) and RTD (R2 = 0.39, P < 0.01). Furthermore, the RBE's protection against muscle damage permitted the estimation of fatigue-associated neuromuscular performance decrements following eccentric exercise. Novelty The repeated bout effect protects peak isotonic power. Protection of peak power relates to preserved rates of torque and velocity development, but more so rate of velocity development. The repeated bout effect has little influence on indices of neuromuscular fatigue.
Palabras clave
EMG; activation volontaire; contractions isotoniques; diminution de force à basse fréquence prolongée; electromyography; fatigue neuromusculaire; isotonic contractions; lésion musculaire; muscle damage; neuromuscular fatigue; prolonged low frequency force depression; voluntary activation; électromyographie
Texto completo:
1
Bases de datos:
MEDLINE
Asunto principal:
Adaptación Fisiológica
/
Músculo Esquelético
/
Fatiga Muscular
/
Mialgia
/
Contracción Muscular
Límite:
Adult
/
Humans
/
Male
Idioma:
En
Revista:
Appl Physiol Nutr Metab
Asunto de la revista:
CIENCIAS DA NUTRICAO
/
FISIOLOGIA
/
MEDICINA ESPORTIVA
/
METABOLISMO
Año:
2021
Tipo del documento:
Article
País de afiliación:
Canadá