Amy Hudson and Dr. James Fisher talk with Lauren Colenso-Semple about the science of female muscle physiology and how hormonal fluctuations impact strength training.

They explore the misconceptions around women’s hormones, the underrepresentation of women in research, and whether training recommendations should differ between men and women. Lauren breaks down the truth about menstrual cycles, menopause, and testosterone, explaining why cycle-based training plans are misleading and how women can train effectively at any stage of life.

• Lauren Colenso-Semple is a scientist and science communicator who specializes in female muscle physiology. Her extensive research is primarily focused on how hormonal fluctuations—whether from the menstrual cycle or hormonal contraceptives—affect performance and exercise adaptations.
• Lauren explains the key hormonal factors at play, how they change throughout a woman’s life, and why these differences matter in strength training.
• The truth about menopause and muscle health—Menopause is just a moment in time, marking the last menstrual cycle after 12 months of no period.
• Lauren breaks down the historical misconceptions around hormones and strength training, revealing how outdated beliefs have shaped fitness advice for women—and why it’s time to rethink them.
• How much does testosterone matter for muscle growth? While it’s essential for initial muscle development during puberty, Lauren reveals it’s not the sole determinant of how much muscle a woman can gain through strength training.
• Why are women underrepresented in strength training research? 
• According to Lauren, researchers have historically avoided studying female athletes due to the complexity of tracking hormonal cycles, leading to a lack of high-quality data.
• Lauren and Dr. Fisher uncover why men are naturally better at gaining muscle than women.
• Should training recommendations for women be different from men’s? Lauren argues that to truly understand sex-based differences in training, we need better research methods that account for women’s physiology without overcomplicating programming.
• Lauren reveals that the menstrual cycle isn’t always 28 days—and that’s normal.
• Despite the common textbook diagram, cycle lengths can vary between 21 and 37 days, and hormone patterns are rarely identical from month to month.
• Amy and Lauren explore whether women should avoid strength training during certain cycle phases. 
• Research shows no significant differences in muscle-building potential across the cycle, meaning women don’t need to skip or modify workouts based on hormone fluctuations alone.
• Some personal trainers still tell women to avoid strength training at certain times, but Lauren warns that this kind of advice disrupts consistency, misleads clients, and isn’t backed by science.
• Lauren explains how trying to match workouts to hormonal phases adds unnecessary complexity and ignores fundamental principles of progression and consistency. Strength training should be done consistently throughout the cycle, with no need for major adjustments unless personal symptoms—such as fatigue or cramps—warrant modifications.
• Lauren and Dr. Fisher caution against overcomplicating strength training, pointing out that fitness trainers often do this to sell programs rather than to help women train effectively.
• Why strength training is critical as you age—After your 30s, muscle mass and strength naturally decline, but lifting weights can slow or even reverse this process, keeping you strong and independent.
• One of the most powerful benefits of strength training is its ability to reshape not just your body but also your confidence, longevity, and overall health.
• Lauren shares stories of women who struggled with fitness for years, jumping from cardio to group classes to online programs—until they found strength training and finally saw lasting results.
• The empowering effect of getting stronger.
• Amy and Lauren discuss strength training during pregnancy. They share how, with proper guidance, lifting weights can be safe and beneficial for both mom and baby, helping with strength, mobility, and postpartum recovery.
• Why male coaches need to engage in this conversation—Dr. Fisher stresses that understanding female physiology isn’t optional for trainers, and even a basic knowledge of hormone cycles can help them coach women more effectively.
• Dr. Fisher’s message to personal trainers and coaches: cycles are a big part of a woman’s life and a big part of a woman’s training. The least you can do is understand how to train them during these phases. 

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