Study on the electromyographic activation of lower limbs during the menstrual cycle phases

Abstract

The purpose of this study was to investigate the influence of the Menstrual Cycle on the activation of thigh and hip muscles using surface electromyography (SEMG). Fifteen college female students (22.2 ± 2.5 yrs old; 60.4 ± 7.5 kg; 160.8 ± 4.3 cm; 27.1 ± 2.85% fat) with regular menstrual cycle who were not taking oral contraceptives participated in this study. Samples were collected according to the menstrual cycle phases, which were divided into: (a) Follicular Phase (collected between the 3rd and 5th day); (b) Ovulatory Phase (collected between the 9th and 15th day); and (c) Luteal Phase (collected between 21st and 28th day). The test consisted of assessing muscle activation in 3 sets of 5 sec in maximum isometry using a Smith machine squat exercise. Statistical analysis indicated that the SEMG activation of the muscles did not show significant differences during the three menstrual cycle phases. Thus, the present study suggests that hormonal fluctuations arising from the menstrual cycle do not alter the EMG activation of the lower extremity muscles during the Smith machine squat exercise.