Menstrual cycle and strength levels in women: a pilot study

Abstract

It is speculated that hormonal fluctuations during the different menstrual cycle (MC) phases can influence physiological systems, such as musculoskeletal, and can also impact physical performance and quality of life. The aimed to check and compare the effects of MC on women's strength levels. The sample was made up of 18-30 years old women, who were using (G1) or not (G2) Oral Contraceptives (OC). Hormonal concentrations were determined using blood extraction, while muscle strength (FM) was assessed through the maximal dynamic strength (1RM) and muscle power tests at 40%, 60%, and 80%. The data were processed using two-factor ANCOVA (group and time), at a significance level of p < 0.05. Hormonal values showed greater significant differences in almost all hormones and G1 phases. The results of the FM tests showed a significant reduction of 1 RM (day 21) in G1, with a moderate effect size on days 21 and 11. In the G1 muscle power (MP) test, on day 01 there was a significant increase in 60% concerning day 11 and day 21. It can be considered that the hormonal behavior of both groups was maintained throughout the evaluations. Regarding FM manifestations, it is suggested that regular MC, without the use of OC, induces a reduction in FM levels during days 11 and 21 in women. However, the group that used OC had a larger effect size on 40% on day 01 and 40% on day 21.