Effects of caffeine-created creatine supplementation under the strength of musculation practicants

Abstract

Introduction: Scientific evidence has shown that caffeine and / or creatine supplementation might increase strength. However, there is some data pointing out that combining the two can annul this effect. Objective: To evaluate the effects of creatine and caffeine supplementation on muscle strength gains by men. Materials and Methods: Strength training practitioners were randomly divided into four groups (control group, creatine group, caffeine group, creatine + caffeine group). For four weeks the experimental groups were supplemented with creatine (5g/day), caffeine (5mg/kg body weight) or both (creatine+caffeine). The force was evaluated by the exercises of bench press and knee extension before the supplementation, after seven days and after 28 days of supplementation. Results were expressed as mean ± standard error. Differences were analysed using ANOVA followed by Bonferroni test adopting values of p<0.05 for significance level. Results: The control group did not change the force at any time. The group supplemented with creatine increased strength in the knee extension after 7 days (54.5 ± 4.8 vs. 57.7 ± 5.1kg). The group supplemented with caffeine increased the strength in the knee extension after 7 days (67.0 ± 9.0 vs. 72.0 ± 7.8kg) and after 28 days (67.0 ± 9.0 vs. 72.0 ± 7.6kg). The group supplemented with both substances increased strength in the knee extension only after 28 days (56.2 ± 7.4 vs. 60.2 ± 7.0kg). Conclusion: Our data suggest that supplementation of creatine and caffeine in an associated way promotes a reduction of the ergogenic effects when com