I have just participated in my first challenge. It was a competition to run 48 miles (77.25 km.) as fast as possible - I ended as #5. I did not schedule more runs that I had planned. I did a few longer runs than planned but nothing serious.
I have signed up to a new challenge, this time a team challenge. The teams are all of the Nordic countries and the challenge starts tomorrow.
This challenge thing is quite fun and works as an extra carrot to go running and the thing is everybody has home court advantage.
Try it out! challenge me if you want to, I am up for it.