| Autor: |
Ferreira LHB; Metabolism, Nutrition and Strength Training Research Group (GPMENUTF), Federal University of Paraná (UFPR), Curitiba 81531-980, PR, Brazil., Forbes SC; Department of Physical Education Studies, Brandon University, Brandon, MB R7A 6A9, Canada., Barros MP; Institute of Physical Activity Sciences and Sports, Universidade Cruzeiro do Sul, São Paulo 07115-000, SP, Brazil., Smolarek AC; Metabolism, Nutrition and Strength Training Research Group (GPMENUTF), Federal University of Paraná (UFPR), Curitiba 81531-980, PR, Brazil., Enes A; Metabolism, Nutrition and Strength Training Research Group (GPMENUTF), Federal University of Paraná (UFPR), Curitiba 81531-980, PR, Brazil., Lancha-Junior AH; Laboratory of Clinical Investigation: Experimental Surgery (LIM 26), Clinic's Hospital of Medical School, University of Sao Paulo, Sao Paulo 05508-030, SP, Brazil., Martins GL; Laboratory of Clinical Investigation: Experimental Surgery (LIM 26), Clinic's Hospital of Medical School, University of Sao Paulo, Sao Paulo 05508-030, SP, Brazil., Souza-Junior TP; Metabolism, Nutrition and Strength Training Research Group (GPMENUTF), Federal University of Paraná (UFPR), Curitiba 81531-980, PR, Brazil. |
| Abstrakt: |
The effects of acute caffeine supplementation on muscular strength remain unclear. We examined the effects of two different doses of caffeine on muscle strength and calcium in plasma compared to placebo using a crossover, randomized, double-blind, placebo-controlled design. Twenty-one (n = 21) recreationally resistance-trained participants were randomly assigned into three experimental conditions: 6 mg·kg bw−1 of caffeine (CF6); 8 mg·kg bw−1 of caffeine (CF8); or placebo (PLA), with a 7-day washout period between conditions. Muscular strength assessments were made for both upper (bench press) and lower body muscles (squat and deadlift). Calcium release in plasma was measured on five different occasions. Bench press (CF8: 100.1 ± 1.9 kg; PLA: 94.2 ± 2.5 kg), deadlift (CF8: 132.8 ± 3.5 kg; PLA: 120.7 ± 5.7 kg), and squat (CF8: 130.1 ± 4.9 kg; PLA 119.4 ± 5.4 kg) strength were all significantly (p < 0.001) improved in CF8 compared to PLA. Calcium release in plasma was significantly increased in CF8, whereas no changes were observed in CF6 or PLA. Overall, 8 mg·kg bw−1 of caffeine appears to be an effective dose to optimize upper and lower body muscular strength and calcium release in recreationally trained participants. |
