Abstract
Training volume is one of the critical variables required to promote resistance
training benefits (e. g., hypertrophy, muscular strength). Thus,
strategies to improve training volume are required. We tested the hypothesis
that there is an increase in performance and reduction in the rate of perceived
exertion in strength training with caffeine supplementation, carbohydrate mouth
rinse, and a synergistic effect of caffeine supplementation plus carbohydrate
mouth rinse. We recruited 29 physically active women: 24±4 years,
60.0±7.9 kg, 161.0±6.0 cm. This study was a
double-blind, randomized, placebo-controlled, and crossover one. The subjects
performed all sessions of strength training under different conditions: caffeine
(6.5 mg·kg−1 body mass); carbohydrate
(6 g of maltodextrin rinsed for 10 s); caffeine plus
carbohydrate; or placebo. We applied the ANOVA for repeated measures through the
null-hypothesis statistical test, and the Bayes factors analyses approach. The
subjects showed significant improvement in the total repetitions
(P<0.01; BF10 ~99%) for both lower and upper
limb exercises in all conditions compared to placebo without difference among
interventions. The rate of perceived exertion (P>0.05) did not differ
among interventions. However, BF10 analyses showed a higher
probability of lower RPE for CAF intervention. We conclude that either caffeine
supplementation or carbohydrate mouth rinse can improve performance in
resistance training. There is no additional effect of caffeine plus
carbohydrate.
Key words
exercise - resistance exercise - fatigue - perceived exertion
