Usually, these female athletes are across the globe, representing different teams. But when they come together to prepare to play for the Australia's national women's football team, their menstrual cycles sync up.
"The girls all seem to get in sync with each other in terms of when their cycle is as soon as they come into camp," the national team's physician, Dr Brandi Cole, told Sydney Morning Herald.
"It is absolutely crazy. One will come to me for some meds for premenstrual pain and then the next minute half the team’s coming to me. It's a known phenomenon."
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Dr Cole said the players monitor their periods constantly as part of their training regimen. And when they're "out of camp", meaning when they're not playing international competition for the Matildas, their periods then become out of sync with one another.
"By the time we're in a big camp they're all in sync together... That's the good thing about menstrual cycle monitoring - they're starting to learn about themselves, which empowers our female athletes to get the best out of their bodies."