Stressor-induced increase in muscle fatigability of young men and women is predicted by strength but not voluntary activation.
J Appl Physiol (1985)
; 116(7): 767-78, 2014 Apr 01.
Article
en En
| MEDLINE
| ID: mdl-24526582
This study investigated mechanisms for the stressor-induced changes in muscle fatigability in men and women. Participants performed an isometric-fatiguing contraction at 20% maximal voluntary contraction (MVC) until failure with the elbow flexor muscles. Study one (n = 55; 29 women) involved two experimental sessions: 1) a high-stressor session that required a difficult mental-math task before and during a fatiguing contraction and 2) a control session with no mental math. For some participants (n = 28; 14 women), cortical stimulation was used to examine mechanisms that contributed to muscle fatigability during the high-stressor and control sessions. Study two (n = 23; nine women) determined the influence of a low stressor, i.e., a simple mental-math task, on muscle fatigability. In study one, the time-to-task failure was less for the high-stressor session than control (P < 0.05) for women (19.4%) and men (9.5%): the sex difference response disappeared when covaried for initial strength (MVC). MVC force, voluntary activation, and peak-twitch amplitude decreased similarly for the control and high-stressor sessions (P < 0.05). In study two, the time-to-task failure of men or women was not influenced by the low stressor (P > 0.05). The greater fatigability, when exposed to a high stressor during a low-force task, was not exclusive to women but involved a strength-related mechanism in both weaker men and women that accelerated declines in voluntary activation and slowing of contractile properties.
Palabras clave
Texto completo:
1
Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Estrés Psicológico
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Volición
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Músculo Esquelético
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Fatiga Muscular
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Fuerza Muscular
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Contracción Isométrica
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Corteza Motora
Tipo de estudio:
Prognostic_studies
/
Risk_factors_studies
Límite:
Adolescent
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Adult
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Female
/
Humans
/
Male
Idioma:
En
Revista:
J Appl Physiol (1985)
Asunto de la revista:
FISIOLOGIA
Año:
2014
Tipo del documento:
Article
Pais de publicación:
Estados Unidos