Last Sunday, Rose Lavelle scored the goal that confirmed the United States’ Women’s World Cup triumph. On Monday, her period began.

Lavelle’s coaches knew this because, in France, the American team deployed an unprecedented programme to minimise the adverse performance impact of the menstrual cycle. In their search for marginal gains, the team contracted an expert consultant to provide research-based insight on the next frontier in sports science.

“One emerging issue in women’s sport is the menstrual cycle and its impact on performance, player health and injury risk,” explains Dawn Scott, the USWNT’s fitness coach, exclusively to The Telegraph. “I’ve known about these effects, the research, for a long time – but working with 23 players, I had always struggled to know how to accurately monitor that and how to individualise strategies for players.”

Scott, a Brit, joined US Soccer in 2010 after almost a decade with the FA. She arrived expecting a sophisticated sports science programme given the United States’ position at the forefront of women’s football – at the time they had already won two World Cups. Instead, she found a blank canvas. “In some ways I was lucky because there was very little in place,” Scott says. “I was starting from scratch.”