Menstrual Cycle and Muscle Development
Study demystifies questions around the impact of a woman’s cycle on strength training.
Women face conflicting information regarding how to approach training during their monthly cycle. Researchers at McMaster University in Ontario, Canada found that muscle growth in women resulting from resistance training did not vary based on menstrual cycle phase.
“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,” says lead study author Lauren Colenso-Semple, MS, CSCS, a PhD candidate in Integrative Physiology at McMaster University. “Women who want to lift weights and recondition their muscles should feel free to do so in any phase of their cycle. There are no physiological differences in response to the exercise,” says principal investigator Stuart Phillips, PhD, professor in Kinesiology and in the School of Medicine, McMaster University. “It is important to tailor your training to how you feel.”
The research is available in the Journal of Physiology (2025; doi:10.1113/JP287342).
Shirley Eichenberger-Archer, JD, MA
Shirley Eichenberger-Archer, JD, MA, is an internationally acknowledged integrative health and mindfulness specialist, best-selling author of 16 fitness and wellness books translated into multiple languages and sold worldwide, award-winning health journalist, contributing editor to Fitness Journal, media spokesperson, and IDEA's 2008 Fitness Instructor of the Year. She's a 25-year industry veteran and former health and fitness educator at the Stanford Prevention Research Center, who has served on multiple industry committees and co-authored trade books and manuals for ACE, ACSM and YMCA of the USA. She has appeared on TV worldwide and was a featured trainer on America's Next Top Model.
