Habitual Caffeine Consumption Does Not Interfere With the Acute Caffeine Supplementation Effects on Strength Endurance and Jumping Performance in Trained Individuals.

The long-standing caffeine habituation paradigm was never investigated in strength endurance and jumping exercise performance through a straightforward methodology. The authors examined if habitual caffeine consumption would influence the caffeine ergogenic effects on strength endurance and jumping performance as well as perceptual responses. Thirty-six strength-trained individuals were mathematically allocated into tertiles according to their habitual caffeine consumption: low (20 ± 11 mg/day), moderate (88 ± 33 mg/day), and high consumers (281 ± 167 mg/day). Then, in a double-blind, crossover, counterbalanced fashion, they performed a countermovement vertical jump test and a strength endurance test either after caffeine (6 mg/kg) and placebo supplementation or after no supplementation (control). Perceptual responses such as ratings of perceived exertion and pain were measured at the termination of the exercises. Acute caffeine supplementation improved countermovement vertical jump performance (p = .001) and total repetitions (p = .004), regardless of caffeine habituation. Accordingly, analysis of absolute change from the control session showed that caffeine promoted a significantly greater improvement in both countermovement vertical jump performance (p = .004) and total repetitions (p = .0001) compared with placebo. Caffeine did not affect the rating of perceived exertion and pain in any exercise tests, irrespective of tertiles (for all comparisons, p > .05 for both measures). Caffeine side effects were similar in low, moderate, and high caffeine consumers. These results show that habitual caffeine consumption does not influence the potential of caffeine as an ergogenic aid in strength endurance and jumping exercise performance, thus challenging recommendations to withdraw from the habitual caffeine consumption before supplementing with caffeine.

Pressão arterial e PSE em múltiplas séries de exercício resistido de diferentes intensidades / Blood pressure and RPE during multiple sets of resistance exercise at different intensities

Estudos equalizaram o volume das séries de exercício resistido (ER), impossibilitando estabelecer o efeito isolado da intensidade sobre a pressão arterial sistólica (PAS), diastólica (PAD) e freqüência cardíaca (FC). Adicionalmente, sugere-se uma associação entre a PSE e estas variáveis durante ER. O estudo objetivou analisar os efeitos isolados da intensidade do ER sobre a PAS, PAD e FC no decorrer de múltiplas séries e verificar a associação entre estas variáveis e a PSE. Oito homens saudáveis executaram o teste de 1 RM e, posteriormente, executaram cinco séries de 10 repetições em intensidade de 50% ou 70% de 1 RM (ordem aleatória). Medidas da PAS, PAD, FC foram realizadas em repouso, durante150 segundos de pausa entre as múltiplas séries de ER (medidas da PSE), e durante a recuperação final. A PAS e a PSE foram maiores na intensidade de 70% do que em 50% de 1 RM (p = 0,02). Os valores de PAS nas múltiplas séries foram maiores do que os medidos em repouso ou na fase de recuperação final, tanto em 50% quanto em 70% de 1 RM. Não houve efeito da intensidade sobre a PAD, pressão arterial média ou FC, embora a FC tenha sido maior no decorrer das múltiplas séries do que em repouso ou na recuperação final. A sobrecarga do sistema cardiovascular parece ser maior em múltiplas séries de ER em 70% do que em 50% de 1 RM. Nesta intensidade, a PSE aumenta progressivamente com as séries, mas essa resposta não está associada às respostas cardiovasculares.

Previous studies have equalized the resistance exercise (RE) volume which caused difficulties to establish the isolated RE intensity effects on systolic (SBP) and diastolic blood pressuresand heart rate (HR). In addition, it has been suggested a relationship between rating of perceived exertion (RPE) and these variables during RE sessions. To analyze the effects of the intensity of RE on the SBP, DBP and HR over the course of multiple sets and investigate the association between these variables andthe RPE. Eight healthy males underwent an one-repetition maximum (1RM) test and thereafter, five sets of 10 repetitions at 50% and 70% of 1RM (random order). Measures of SBP, DBP and HR were carried out at rest, during 150 seconds of multiple sets recovery (RPE measures) and at final recovery phase. SBP and RPE were higher at 70% than 50% of 1RM (p = 0.02). The SBP values during the multiple sets were higher than the values obtained at rest or final recovery phase in 50% as well as in 70% of 1RM. There were no intensity effects in DBP, mean blood pressure and HR even though the higher HR values during multiple sets than rest or final recovery phase. The cardiovascular overload during RE sessions appears tobe greater in 70% than 50% of 1RM. In this intensity the RPE increases progressively as the multiple sets are performed, but its response is not associated with cardiovascular responses.