Wingate Performance And Surface EMG Frequency Variables Are Not Affected By Caffeine Ingestion

Greer, Felicia; Morales, Jacobo; Coles, Michael; Jackson, C. G. R.

doi:10.1097/00005768-200505001-00231

Cited by 6 publications

(9 citation statements)

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“…Vandewalle and colleagues (1991) observed a parallel decline in power output and integrated EMG of the vastus lateralis (average values not reported by the authors) during a 45-second cycle sprint, and suggested a progressive attenuation of spatial and/or temporal recruitment of motor units during the exercise. These findings are supported by another study that reported a ~15% (P < 0.05) decline in the integrated EMG of the plantar flexors and a ~15-19% (P < 0.05) reduction in the median frequency of the EMG power spectrum of the plantar flexors and the knee extensors during a 30-s Wingate anaerobic cycle sprint (Greer et al 2006). While Hunter et al (2003) did not observe any change in the EMG amplitude of the vastus lateralis muscle during a 30-second cycle sprint (whereas power output declined), the authors reported a shift of the mean power frequency towards lower values (14.7%; P < 0.05).…”

Section: Electromyographic Events During Single-sprint Exercisesupporting

confidence: 75%

Electromyography Assessment of Muscle Recruitment Strategies During High-Intensity Exercise

Billaut¹

2011

Advances in Applied Electromyography

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Section: Electromyographic Events During Single-sprint Exercisesupporting

confidence: 75%

Electromyography Assessment of Muscle Recruitment Strategies During High-Intensity Exercise

Billaut¹

2011

Advances in Applied Electromyography

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“…However, the effect of caffeine on muscle contractility and function during moderateto-high intensity exercise remains less clear (17,36,43). While some studies reveal little or no significant improvement in high-intensity performance with the ingestion of caffeine (4,19,20), other studies have shown an increase in this variable Fig. 4.…”

Section: Discussionmentioning

confidence: 99%

“…There is some evidence (32,44) that the direct effect of caffeine on skeletal muscle in improving endurance performance may be due to an increase in force output for a given neural input. Furthermore, some studies also indicate that caffeine may assist in short-term power activity (5,42,48), while other studies do not support this conclusion (4,8,18,19,20).…”

mentioning

confidence: 97%

Effect of physiological levels of caffeine on Ca²⁺ handling and fatigue development in Xenopus isolated single myofibers

Rosser

Walsh²,

Hogan³

2009

American Journal of Physiology-Regulatory, Integrative and Comp

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MC. Effect of physiological levels of caffeine on Ca 2ϩ handling and fatigue development in Xenopus isolated single myofibers. Am J Physiol Regul Integr Comp Physiol 296: R1512-R1517, 2009. First published March 4, 2009 doi:10.1152/ajpregu.90901.2008The purpose of the present study was to determine whether exposure to exogenous physiological concentrations of caffeine influence contractility, Ca 2ϩ handling, and fatigue development in isolated single Xenopus laevis skeletal muscle fibers. After isolation, two identical contractile periods (separated by 60-min rest) were conducted in each single myofiber (n ϭ 8) at 20°C. During the first contractile period, four fibers were perfused with a noncaffeinated Ringer solution, while the other four fibers were perfused with a caffeinated (70 M) Ringer solution. The order was reversed for the second contractile period. The single myofibers were stimulated during each contractile period at increasing frequencies (0.16, 0.20, 0.25, 0.33, 0.50, and 1.0 tetanic contractions/s), with each stimulation frequency lasting 2 min until fatigue ensued, defined in this study as a fall in tension development to 66% of maximum. Tension development and free cytosolic [Ca 2ϩ ] (fura-2 fluorescence spectroscopy) were simultaneously measured. There was no significant difference in the peak force generation, time to fatigue, cytosolic Ca 2ϩ levels, or relaxation times between the noncaffeinated and caffeinated trials. These results demonstrate that physiological levels of caffeine have no significant effect on Xenopus single myofiber contractility, Ca 2ϩ handling, and fatigue development, and suggest that any ergogenic effects of physiological levels of caffeine on muscle performance during contractions of moderate to high intensity are likely related to factors extraneous to the muscle fiber.

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“…O mesmo não se pode dizer com relação aos exercícios supramáximos de curta duração que utilizaram de protocolos closed-loop do tipo time-trial com tempo inferior a 60 s ou ainda quando os esforços são intermitentes, onde a ingestão de cafeína parece não proporcionar qualquer alteração no desempenho físico (CROWE, 2006;GREER et al, 2006;LORINO et al, 2006 redução (~3,1%) significante do tempo (CAF = 71,1 ± 2,0 s, PL = 73,4 ± 2,3 s; P = 0,02), contrapondo nossos achados. Esse estudo foi o único encontrado na literatura que utilizou contrarrelógio de 1 km.…”

Section: Discussionunclassified

<b>Efeito da ingestão de cafeína sobre o desempenho físico e estado de humor de ciclistas</b> doi: 10.4025/reveducfis.v24i2.16991

Carneiro

Bortolotti²,

Camata³

et al. 2013

R. Educ. Fís. UEM

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RESUMOO objetivo do estudo foi analisar os efeitos da ingestão de cafeína sobre o desempenho físico e estado de humor de ciclistas em teste contrarrelógio de 1 km. Dez ciclistas do sexo masculino realizaram aleatoriamente um teste contrarrelógio de 1 km em duas condições experimentais: ingestão de cafeína (CAF -6 mg.kg -1 ) e placebo (PL) 60 min antes do teste. Durante os testes foram obtidas as medidas de tempo total e estado de humor pelo questionário de Brunel (BRUMS). Para comparações dos parâmetros tempo total e estado de humor, foi utilizado o teste t de Student pareado e teste Wilcoxon, respectivamente. Nenhuma diferença estatisticamente significante foi encontrada no tempo total e no estado de humor nas condições CAF e PL (P>0,05). Os resultados sugerem que a cafeína não melhora o desempenho físico e nem altera o estado de humor dos atletas em um teste contrarrelógio de 1 km. Nos últimos anos, a cafeína tem sido apontada como um recurso ergogênico de caráter nutricional capaz de exercer efeito positivo em exercícios aeróbios (esforços moderados de média e longa duração) e anaeróbios (esforços de alta intensidade e curta duração), com o intuito de amenizar o processo de fadiga e, consequentemente, melhorar o desempenho físico influenciando o resultado final (DOHERTY; SMITH, 2004;SPRIET;GIBALA, 2004;ALTIMARI, 2010).Particularmente com relação aos exercícios de característica anaeróbia, poucos estudos têm procurado investigar os efeitos ergogênicos da cafeína sobre o desempenho físico (ALTIMARI et al., 2006;ASTORINO;ROBERSON, 2010). Altimari (2010), Astorino e Roberson (2010) sugerem que o aumento da força e potência muscular acompanhado de maior tolerância ao exercício após a ingestão de cafeína possa ocorrer pela ação no sistema nervoso central (SNC) em função de seu efeito antagônico nos receptores de adenosina, melhorando a transmissão dopaminérgica pré e pós-sináptica e, consequentemente, aumentando a taxa de sinapse entre os motoneurônios e a propagação dos sinais neurais entre o córtex cerebral e a

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Wingate Performance And Surface EMG Frequency Variables Are Not Affected By Caffeine Ingestion

Cited by 6 publications

References 0 publications

Electromyography Assessment of Muscle Recruitment Strategies During High-Intensity Exercise

Electromyography Assessment of Muscle Recruitment Strategies During High-Intensity Exercise

Effect of physiological levels of caffeine on Ca²⁺ handling and fatigue development in Xenopus isolated single myofibers

<b>Efeito da ingestão de cafeína sobre o desempenho físico e estado de humor de ciclistas</b> doi: 10.4025/reveducfis.v24i2.16991

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Wingate Performance And Surface EMG Frequency Variables Are Not Affected By Caffeine Ingestion

Cited by 6 publications

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Electromyography Assessment of Muscle Recruitment Strategies During High-Intensity Exercise

Electromyography Assessment of Muscle Recruitment Strategies During High-Intensity Exercise

Effect of physiological levels of caffeine on Ca2+ handling and fatigue development in Xenopus isolated single myofibers

<b>Efeito da ingestão de cafeína sobre o desempenho físico e estado de humor de ciclistas</b> doi: 10.4025/reveducfis.v24i2.16991

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Effect of physiological levels of caffeine on Ca²⁺ handling and fatigue development in Xenopus isolated single myofibers