"Some women also experience symptoms related to their menstrual cycle such as low energy, pain or bloating. According to one recent study of female rugby players, 93% of them reported cycle-related symptoms, and 67% thought these affected their athletic performance.
Even so, the menstrual cycle is among the least studied aspects of human biology. Last year, Chelsea Women became the first football club in the world to start tailoring its players’ training to their menstrual cycles, although there’s little evidence that this is effective.
There’s a very thin layer of evidence to suggest that there may be ways in which you can manipulate training based on where someone is in their menstrual cycle. The problem is that if you’re not measuring the hormones, you don’t actually know what’s happening. Just because you have a normal cycle length, doesn’t mean that your hormones are behaving in a normal fashion,"