MANCHESTER, England, April 30 (Reuters) - A growing chorus of women's soccer players have called for research into anterior cruciate ligament (ACL) tears, one of sport's most debilitating injuries and one that women are between two and six times more likely to suffer than men.

Project ACL, which was launched on Tuesday by several collaborating partners with hopes of reducing ACL injuries in the women's game, is a response to that call, said Alex Culvin of global players' union FIFPRO.

FIFPRO, the Professional Footballers' Association, Nike ( NKE ) and Leeds Beckett University have teamed up for the three-year project which will focus on England's 12-team Women's Super League (WSL).

"The combination of ACL injury plus the higher profile of the game and the players themselves rightly calling for more research means that it's very ripe for investigation," Culvin, FIFPRO's head of strategy and research for women's football, told Reuters on a Zoom call.

"The players are invested and organisations are invested and we rightly owe it to the players to provide better conditions and understanding of their environments."

According to a UEFA study, a 23-player squad can expect to see three ACL injuries over four years.

But while numerous high-profile players have made headlines for recent ACL tears including Australia and Chelsea striker Sam Kerr, who tore hers in January, Culvin said there has not been a huge explosion of cases.

"We know that ACLs have existed for as long as women's football has existed," she said.

What has been on the rise is the professionalism in the women's game which has meant greater workloads and crowded schedules. But the research into the injury, much of which focuses on single risk factors such as the menstrual cycle, has not kept pace.

"It's not possible to adopt a reductionist approach and suggest that there is one singular risk factor," Stacey Emmonds, a lecturer at Leeds Beckett, told Reuters.

"We know that the risk factors for injury are multi-factorial, and therefore there's a need to kind of understand the holistic environment and the playing conditions."

'PLAYER VOICE'

Project ACL will review existing research and injury reduction programmes, study teams' resources and access to facilities, and track in real time factors such a player's workload and travel.

"What is novel is bringing the player voice to the project, so really understanding players' experiences and perceptions of their environments that they're working within," Emmonds said.

England and Barcelona defender Lucy Bronze, who did her dissertation in ACL injuries in women's sports at Leeds Metropolitan University, said the cry from players for more research stems from the injury's severity.

"The recovery time is one of the longest in terms of common injuries, and it tends to be if you've done your ACL that's it, you know that you're missing the next tournament or the Champions League final, the end of the season, whatever it is, for that reason it's spoken about so much," Bronze said.

"And even when you get back I think there's an expectation that you think 'Oh I'm going to be back to my best,' but there's another process after that (because) your body's changed because you've had to go through a major surgery."

Culvin highlighted that an ACL tear makes a player more susceptible to a repeat of the injury. Earlier this month, Scotland and Glasgow City forward Fiona Brown suffered her fourth ACL tear in eight years. And, Culvin added, an ACL tear often leads to osteoarthritis in that knee later in life.

"You only play football until you're 35, you've potentially got another 60 years of your life still to live, and it's incredibly debilitating physiologically and also mentally as well," she said.

"So yeah, it's important that we get this right and keep a light shone on the injury."