This is a documentary from the BBC World Service.

I'm Leanne Sanderson, broadcaster and former England professional footballer.

I began playing football in South East London at the age of five years old

for an all-boys team because there was no other girls' teams in the local area.

I then got scouted for Arsenal at nine years old, made my debut for the Arsenal 30 when I was 14, and never look back.

In 2016, I suffered an ACO injury whilst playing for the Western New York Flash.

ACL stands for anterior cruciate ligament.

Football-focused studies suggest women are six times more likely to suffer ACL injuries

compared to men and are 25% less likely to make a full return to high-level football.

But let's start at the top.

What exactly is an ACL injury?

So this is my knee.

This is the kneecap in front of the knee.

This is my shin bone, the tibia, my thigh bone, the femur underneath here.

My muscles are around there and the ACL is in the middle.

This is Fisio-Harvard Monkki at the Oslo Sports Trauma Research Center in Norway.

And it's supposed to stop the rotation of the tibia in this direction.

So if it goes too far, it ruptures and the thigh bone will slide off the shin bone and come back in.

That's when the ACL ruptures.

And here you can see the scar and this is where they take the tendon out to replace the ACL.

And this is an experience I only know too well.

And I'm not the only footballer.

...