Changes in insulin-like growth factor 1 and quadriceps muscle size in follicular stage compared to luteal stage in adaptation to resistance training in young women

Introduction: Menstrual cycle may affect the training of strength and muscle size. The aim of the present study was to determine the effect of exercise volume distribution in the 2 follicular and luteal phases of the menstrual cycle on serum IGF-1 and muscle mass in women. Materials and Methods: 20 women with a mean age of 22 ± 5 years, without contraceptive use and a history of eight weeks of resistance training were selected. Each subject had 8 training sessions on one leg in the first 14 days of menstruation and 2 training sessions on the second 14 days of menstruation (fruiting in the follicular period) and the other leg had 2 training sessions on the first 14 days of menstruation and 8 training sessions on the second 14 days of menstruation (Fertility in the luteal period). Results: Muscle diameter in follicular exercise (0.67 ± 0.34 cm) was higher than luteal exercise (0.46. 0.41 cm). Also, insulin-like growth factor increased in both groups (13%) regardless of the type of exercise schedule. Conclusion: Therefore, although fluctuations in sex hormones during the menstrual cycle may affect muscle growth, but this study showed that at least this different muscle growth is not due to an increase in insulin-like growth factor 1. As a result, it is recommended that menopausal women who do not take birth control pills schedule their strength training based on their individual menstrual cycle.