The Definitive Guide to the World's Dumbest Sport

Fitballing is not a great idea. Find out why.

To show you what not to do, each week STACK brings you a moment from the weight room or sports field gone horribly wrong.

"Fitballing" is a phenomenon in which industrious young people at the beach bury a physioball in the sand and use it as a mini trampoline. If you're an athlete who enjoys jumping off things, we understand you may have a lot of questions about fitballing. To help answer them, we've recruited the fine people of YouTube.

Q: How much weight can a fitball handle?

A: Approximately one child.

Q: Great, I am a child! Should I attempt to backflip off a fitball?

A: Probably not.

Q: What about a front flip?

A: No.

Q: I feel like I'm better at flipping than that.

A: You almost certainly are not.

Q: I'm jusalittle drunk. Whaddya think?

A: Go for it big guy.

Q: What's the worst that can happen? It's sand!

A: This seems pretty bad.

Q: Fine, I won't do it. But as long as I have this physioball with me at the beach, I'd like to hold it in front of me while running full speed at my friend. Should I do that?

A: You should not.

Read more Fitness Fail Friday:

Photo Credit: Getty Images // Thinkstock