No hormonal advantage was observed
Researchers at McMaster University examined whether the menstrual cycle’s phases affect muscle-building responses to resistance training. Contrary to widespread internet claims, the findings showed no significant differences in muscle protein synthesis between cycle phases.
“Our findings conflict with the popular notion that there is some kind of hormonal advantage to performing different exercises in each phase. We saw no differences, regardless of cycle timing,” said Lauren Colenso-Semple, the study’s lead author.
Muscle protein synthesis remains similar during the menstrual cycle phases
To test the theory of cycle syncing, researchers closely monitored the menstrual cycles of healthy young women over 3 months. The study also noted that only about 12% of women experience the “textbook” 28-day cycle with ovulation on day 14.
Participants performed heavy resistance exercises during two distinct menstrual phases: the follicular phase (high oestrogen) and the luteal phase (high progesterone). The scientists used a tracer molecule to track muscle protein synthesis, a key factor in muscle growth.
Results showed that muscle protein synthesis rates did not change significantly based on menstrual cycle phases. “Our work shows that women who want to lift weights and recondition their muscles should feel free to do so in any phase of their cycle,” said Stuart Phillips, supervisor of the study.
Practical implications for cyclists
For female cyclists, especially those incorporating strength training to prevent injury and enhance performance, this research simplifies the approach.
Consistency over complexity: There’s no need to complicate training schedules with detailed cycle tracking. Consistency in training remains the best approach to achieving strength and performance goals.
Listen to your body: Regardless of the phase of the menstrual cycle, tailoring workouts based on personal energy levels, fatigue, and overall health remains essential. “It is important to tailor your training to how you feel,” said Phillips.
While this study offers important clarity, the researchers highlight the need for more extensive research into women’s health and exercise physiology. Future studies might examine how different contraceptives and menstrual irregularities affect training adaptations, potentially providing more individualised insights for female athletes.
