It's a game you play as a kid. This is the first I've heard of there being a professional league.
On the other hand, we also have competitions such as cheese rolling (trying not to get killed by a giant cheese wheel rolling down a hill), so I'm not that surprised.
I did that race twice, dislocated my left shoulder each time. Scariest thing i've ever done.
People have the misapprehension that you're supposed to catch the cheese. No idea why you'd think it's a good idea to catch a rock hard lump whilst running down a hill so fast that if you tense your legs once to slow down you do 3 cartwheels.
Also just remembered - they have local rugby players to catch those who can't stop running from hitting the fence of the house at the bottom. Saw at least one person they missed who smacked into the fence and got carted off by St John's Ambulance.