It’s an idea that’s been enthusiastically embraced on social media: women should sync their training to their menstrual cycle. That means lifting heavier weights around ovulation, then switching to gentler movement such as yoga in the second half of the cycle – because as their hormones fluctuate so does their strength. But there’s not much proof that this is useful, says Dr Marianna Apicella, a researcher at the University of Leicester specialising in female physiology. “High-quality evidence supporting that is seriously lacking,” she says. “There’s not really much concrete evidence for it.” double quotation mark If you’re dealing with cramps, fatigue or low mood, it’s hardly surprising that your performance might dip Apicella’s research looks at muscle-building throughout the hormone fluctuations of the menstrual cycle. She says it has shown there’s no difference between phases. Whether in the early follicular phase, the late follicular phase or the luteal phase, the body’s ability to build muscle appears broadly consistent. In other words, there’s no strong evidence that you’ll gain more strength or muscle at one point in your cycle than …