Mastering the menstrual cycle: How rugby is learning to use period power to improve performance

There is a reason why Eloise Hayward meticulously tracks her menstrual cycle. Four years ago, the Great Britain sevens player suffered extensive ankle ligament damage on the rugby pitch a couple of days before her period was due.

“In the warm-up I remember feeling a bit loose,” says Hayward. “There’s a fine line between feeling loose and primed and game-ready. During the match my ankle went.”

While Hayward admits her training load might have contributed to the injury – at the time she was flitting between rugby league in the summer and union in the winter – she is convinced the timing of her injury was more than coincidental.

Hayward, who recently signed with Leicester Tigers, was in the luteal phase of her menstrual cycle, the fourth and final stage of a woman’s cycle when levels of relaxin, a hormone known to increase ligamentous laxity, start to increase. While female athletes remain woefully understudied in sports science, there is a growing body of literature to suggest that the hormone heightens the risk of ligament injuries.

Hayward’s own injury was enough to pique her interest into how menstrual cycles impact athletic performance. The 24-year-old’s university dissertation, published earlier this year in the International Journal of Environmental Research and Public Health, explored how elite women’s rugby players perceive menstrual cycle risk.

Fear of losing place if take time off

Of 15src elite rugby players from the two top English rugby divisions, the RFL Women’s Super League and Premiership Women’s Rugby in union, 9src per cent considered the menstrual cycl