From the sidelines: One player's fight to return from ACL injury

MANCHESTER, England :Hanna Glas had never heard of an anterior cruciate ligament before the Seattle Reign defender tore one of hers for the first time at age 17 during a Sweden national team development camp.

It would happen three more times over a roller-coaster career for the now-32-year-old Glas, once considered one of the best right backs in the women's game and now a walking encyclopaedia on ACL recovery.

"I remember I was very fatigued, especially in my head mentally," Glas said in an interview with Reuters. "I was performing really well but I just passed the ball, got a late tackle from the striker and my knee kind of pivoted."

ACL injuries have become a hot topic in women's football, with studies showing that women are up to eight times more likely to suffer the injury than men.

The quality of pitches, access to physiotherapy, hormonal fluctuations during the menstrual cycle and properly-fitting boots have all been highlighted among potential contributing factors, with players such as England's Beth Mead, Dutchwoman Vivianne Miedema and Australian Sam Kerr all grudging members of the "ACL club."

Swiss striker Ramona Bachmann and England defender Ella Morris will both miss the July 2-27 European Championship in Switzerland after suffering ACL tears.

Glas will not play at the Euros for Sweden, announcing her international retirement last October to focus on her club career after her string of ACL injuries.

"Two is very tough. Three is extreme. Four, not many people I know have gone through that," she said.

The long recovery time makes the injury a devastating one. Four ACL injuries means about four years off the pitch in a professional career that typically lasts 10 to 15 years.

"I knew something had happened in my knee