Effect of Different Phases of the Menstrual Cycle on the Performance of Muscular Strength in 10RM

The aim of this study was to investigate the effect of the different phases of the menstrual cycle (MC) on muscular strength performance in resistance exercises. Nine healthy and physically active women, aged 27 +/- 7 yrs, body mass 58.2 +/- 5 kg, height 161.1 +/- 4.7 cm and BMI 20.4 +/- 2 kg/m2 participated in the study. All of them had regular MCs (28-31 days), used oral contraceptives and had been experienced in resistance exercises for at least eight months. Muscle strength was evaluated with a 10RM test in the following order: leg press 45 degrees, bench press, leg extension and biceps curl. The tests were performed in the three phases of the MC: follicular (between the 3rd and 5th day of menses), ovulatory (between 9th and 10th days) and luteal (between 17th and 21th days). ANOVA for repeated measures was applied for statistical analysis, data were analyzed in the SPSS 15.0 and level of significance was set at 5% (p<0.05). No significant statistical differences were observed in the mobilized weight between the MC periods in those four exercises. Regarding the leg press exercise, a 5% increment in muscle strength was observed on the luteal phase. In the remaining exercises and phases these differences were not observed. In conclusion, the phases of the MC did not affect performance of muscular strength in resistance exercise, both single and multiple joint, for large or small muscle groups or in different body segments.