Several studies have demonstrated that creatine supplementation can increase the performance in high-intensive exercises involving repeated muscular actions through delaying muscle fatigue and promoting a quick recovery between sets and exercises.
PURPOSE: to analyze the effect of creatine supplementation and resistance exercise on indicators of fatigue in women.
METHODS: Thirty-one women (20.2 ± 2.8 years; 58.8 ± 8.3 kg; 165.2 ± 5.2 cm) were divided by a double-blind design in creatine supplementation (CR, n =16) or placebo (PL, n = 15) groups after 16 weeks of regular resistance training. The creatine supplementation or placebo (maltodextrin) was consumed in four 5 g/day doses during the first five days (20 g/day). Therefore, a single 3 g/day dose was ingested in the following 51 days. The 1-RM test was applied as strength indicator in three exercises (bench press, squat, and arm curl). Muscular endurance was evaluated by the maximal number of repetitions performed up to volunteer exhaustion during four sets at 80% of 1-RM in the three exercises. ANOVA with repeated measures, followed by the post hoc Scheffé test, when P < 0.05, were used for data treatment.
RESULTS: No significant differences in the fatigue index ([(number of repetitions in the first set - number of repetitions in the four set) / (number of repetitions in the first set)]* 100) was found in the muscular endurance during all moments, either in the CR supplemented group or in the PL group and in all exercises: bench press (CR: pre = 62.7 ± 6.4%, post = 65.1 ± 5.9%; PL: pre = 62.8 ± 7.9%, post = 65.8 ± 7.3%), squat (CR: pre = 64.5 ± 14.4%, post = 62.7 ± 13.4%, PL: pre = 64.7 ± 11.1%, post = 63.9 ± 14.0%) and arm curl (CR: pre = 58.7 ± 12.8%, post = 59.0 ± 11.0%, PL: pre = 57.5 ± 14.5%, post = 63.9 ± 7.6%). Besides, an increase in the training volume (load lifted multiplied by the sum of the number of repetitions performed in the four series at every exercise) in all exercises studied when compared to the results obtained before and after supplementation, but such better result was similar in both groups (P>0.05).
CONCLUSION: Creatine supplementation was not able to produce significantly different responses in both muscular fatigue and training volume of women trained with resistance training.
Acknowledgements to CNPq and Integralmédica®