Women footballers are two to six times more likely to tear their ACL than men. That's not a gap — that's a chasm. And the sport has spent too long explaining it away with biology while ignoring everything else.
The NWSL is now joining the WSL, Fifpro, England's PFA, Nike, and Leeds Beckett University in Project ACL — a three-year research initiative that launched in 2024 and is finally asking the harder questions. Not just what's happening inside the body, but what's happening around the player: the pitch surface, the cleat design, the schedule, the weight-room access, the recovery time they're not getting.
The injury list that forced the conversation
The 2023 World Cup made it impossible to look away. Leah Williamson, Beth Mead, Vivianne Miedema, Catarina Macario — all absent with ACL tears. Then the 2024 Paris Olympics: Sam Kerr and Lena Oberdorf both missed it. Of the 20 USWNT gold medalists in Paris, seven had suffered the injury at some point in their careers. At that point, this stops being an unfortunate pattern and starts being a structural failure.
Oberdorf's case is particularly grim. She missed Euro 2025 recovering from her first tear, returned in October, and ruptured it again eight matches later. Kerr's recovery from January 2024 took nearly 20 months before she played again in September 2025. The injury isn't career-ending anymore — but it is career-defining in the worst way.
The biological factors are real and documented: wider hips, narrower knee structure, a tendency to land flat-footed, quad dominance over hamstring strength. Roughly 70% of ACL injuries in women occur without any contact at all. But biology only goes so far as an explanation when girls are consistently given less access to strength training, when cleats are built around a male foot, and when artificial turf — already a known risk factor — remains standard in many women's competitions.
What Project ACL actually does
Since its 2024 launch, the Project ACL team has interviewed more than 30 players and surveyed all 12 WSL clubs on their resources and injury prevention strategies. The same process is now rolling out across the NWSL's 16 clubs. Players will be able to log workload, travel, and recovery data through Fifpro's monitoring tool — the kind of granular tracking that men's leagues have had for years.
Fifpro describes this as the first initiative of its kind to span multiple professional leagues. That's significant, because less than 10% of sports science research centers on women, and most of what exists focuses on amateurs rather than elite professionals. The entire evidence base for women's performance medicine is thin. Project ACL is trying to build it from scratch.
"That understanding requires looking beyond the individual and examining the conditions players compete and train in every day," said Tori Huster, deputy executive director of the NWSLPA. It's a pointed line — a quiet acknowledgment that clubs and leagues have not always made the environment a priority.
The long-term goal is injury-prevention protocols embedded and regulated by clubs and leagues, modeled on the frameworks that now govern concussion management. That took football decades to get right on the men's side. The hope is this moves faster.
"Player health and performance are fundamental to the future of our league, and this is an area where we intend to lead," said NWSL VP of sporting Sarah Gregorius. Whether the league's clubs follow that intention with actual resources — better pitches, proper gym access, saner scheduling — is the part no press release can answer.
