Making a clumsy mistake while trying to do something athletic.
In the film "Napoleon Dynamite" Napoleon throws an orange at Uncle Rico's van. Rico jumps out and puts Napoleon in a headlock. Napoleon elbows Rico and escapes, but as he runs away he attempts to jump a fence and "beefs it". Yes, Napoleon really "beefed it". By the way the "beefing it" was NOT in the script. It was a real "beef" made by the actor playing Napoleon. It was so funny they left it in the film.