The Efficacy of Training Periodization Strategies Adapted to Menstrual Cycle Phases: A Systematic Review of Evidence

Background: The female menstrual cycle features dynamic hormonal fluctuations affecting metabolic parameters, the neuromuscular system, and the biomechanics of the musculoskeletal system. With the advancement of women's sports, the popularization of rigorous training periodization models based on cycle phases (cycle syncing) can be observed on social media. Unfortunately, many of these recommendations rely on anecdotal reports, and the research landscape is further complicated by the widespread use of oral hormonal contraceptives among female athletes. Objective: This study aims to critically evaluate the validity of training periodization according to the menstrual cycle phase in women by comparing evidence-based medicine (EBM) guidelines with the narrative promoted across mass social media. Methods: A systematic review of scientific literature across PubMed and Web of Science databases was performed for the period up to 2026. Studies assessing the impact of hormonal fluctuations on strength parameters, performance metrics (VO2max), joint laxity (anterior cruciate ligament - ACL injury risk), and psychophysical indicators in naturally training women and oral contraceptive users were analyzed. Concurrently, a qualitative analysis of top trends and claims on TikTok, Instagram, and YouTube was carried out. Results: Analysis of scientific literature indicated the stability of performance metrics (VO2​max) and strength indicators across the physiological cycle for most women, undermining the validity of drastic and rigid training load changes promoted online. However, hormonal fluctuations correlate with variability in ligament laxity (increased susceptibility to ACL injuries during the ovulatory phase) and subjective fatigue in the late luteal phase. It was also shown that hormonal contraception abolishes natural sex hormone fluctuations, rendering universal internet templates non-functional. Conclusions: Current EBM guidelines do not support rigid training periodization based strictly on the menstrual calendar, contradicting the dominant mass media trend. Uncritical implementation of schematic training restrictions and dietary constraints can negatively affect athletic progress, bone mineral density, and the relationship with food. The most justified, safe, and scientifically supported alternative to internet templates is individual effort autoregulation, based on ongoing monitoring of psychophysical readiness.