This blog revisits the question of whether sex hormones meaningfully impact sport performance and updates current evidence on the menstrual cycle and athletic training. While hormone fluctuations across the follicular, ovulatory, and luteal phases are real, emerging research continues to show that they do not consistently predict performance changes. Instead, individual symptoms—driven more strongly by energy availability, sleep, stress, training load, and overall health—play a larger role in how athletes feel and perform. The article provides updated, practical training recommendations across the menstrual cycle, emphasizing a flexible, symptom-informed approach rather than rigid phase-based rules.