Abstract
The amount of exercise research studying women has remained relatively limited compared to that of men. This is partially attributed to difficulties controlling for female sex hormone fluctuations during the menstrual cycle. Conflicting evidence suggests estrogen and progesterone may have an impact on exercise responses and muscle adaptations. Some studies correlated high concentrations of estrogen to reduced muscle damage, inflammation, or improved recovery and muscle repair while some studies found no effect. Very few studies have investigated the effect of progesterone on skeletal muscle. Research suggests progesterone may modulate pain perception and reduce muscle fatigue, but the effect has not yet been studied in eumenorrheic women. Therefore, the purpose of this exploratory longitudinal study was to investigate the effect of the three different phases of the menstrual cycle on muscle performance, muscle damage, and soreness after resistance exercise-induced muscle damage. Three healthy, sedentary to moderately active eumenorrheic women, not taking any hormonal contraceptives, performed an exercise-induced muscle damage protocol during each menstrual cycle phases. Measurements of muscle performance, muscle damage and soreness were collected pre-exercise as well as 30-min, 24-, 48-, and 72-hours post exercise of each phase.
The preliminary results suggested that women may experience more muscle pain and larger decrease in muscle performance (strength, endurance, and power) during the follicular phase. Muscle performance may be less decreased and return to pre-exercise values quicker in the ovulatory phase. Although no statistically significant differences (p<0.05) were observed between menstrual cycle phases and time points post-exercise, these results suggest that the ovulatory phase may trigger less muscle damage and quicken muscle recovery compared to the follicular and luteal phases after exercise-induce muscle damage. This study provides insights that could help increase inclusion of women in exercise research. Furthermore, the results of this study will add to the body of knowledge that could help inform practitioners and coaches of best-practice methods for maximizing exercise performance and training adaptations in women.