Acute effects of caffeine on strength and muscle activation of the elbow flexors.
J Strength Cond Res
; 29(2): 513-20, 2015 Feb.
Article
em En
| MEDLINE
| ID: mdl-25029005
ABSTRACT
The purpose of this study was to examine the effects of caffeine on strength and muscle activation of the elbow flexors. Thirteen recreationally active male volunteers (mean ± SD, age 21.38 ± 1.26 years) came to the laboratory 4 times. Visit 1 served as a familiarization visit. During visits 2 through 4, subjects ingested a randomly assigned drink, with or without caffeine (0, 5, or 10 mg·kg of body mass), and performed 3 maximal isometric muscle actions of the elbow flexors 60 minutes after ingestion. Maximal strength and rate of torque development (RTD) were recorded. Electromyographic (EMG) and mechanomyographic (MMG) amplitude and frequency, and electromechanical delay (EMD), and phonomechanical delay (PMD) were measured from the biceps brachii. The results indicated that the ingestion of 0 (placebo), 5, or 10 mg·kg of body mass of caffeine did not significantly influence (p > 0.05) peak torque, RTD, normalized EMG amplitude or frequency, normalized MMG amplitude, or EMD and PMD. Normalized MMG frequency was significantly lower (p ≤ 0.05) following ingestion of 5 mg·kg of body mass of caffeine compared with the placebo trial. This was most likely an isolated finding because MMG frequency was the only variable to have a significant difference across all trials. The results suggested that ingestion of either 5 or 10 mg·kg of body mass of caffeine does not provide an ergogenic effect for the elbow flexors during isometric muscle actions.
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Cafeína
/
Articulação do Cotovelo
/
Força Muscular
/
Estimulantes do Sistema Nervoso Central
/
Contração Isométrica
Tipo de estudo:
Clinical_trials
Limite:
Adult
/
Humans
/
Male
Idioma:
En
Revista:
J Strength Cond Res
Assunto da revista:
FISIOLOGIA
Ano de publicação:
2015
Tipo de documento:
Article