No clue but they do exist. Here is an older German news report https://youtu.be/gfGqZzAdzyM?si=a0djmd50-clPc_so

They have allready spread to Germany.

Just to be pedantic, this would be a dick pic pre-camera.

Yes kind of, they still have a minimum speed people need to adhere to.

Well it is in the name, endurance RACES. It is a race not a test of pure endurance. To test pure endurance you would need to start running or walking or swimming at your own pace and continue till you drop to the ground and the one that can do that for the longest would have the best endurance.

Better late than never.