In Russian, there is the term сгруппироваться ("to group yourself together"), which means "fold your body, bend your legs and arms". This action is believed to be helpful when falling, since it helps one minimize injury.
I looked up translations for сгруппироваться in Multitran and found these:
wrap; ball the legs; draw the knees up to the chest; tuck; tuck oneself up.
Which of them is the term you would most likely use in this sentence:
During training, while trying to perform a move, the athlete failed to ___, and he went sprawling.
Here's a description of this "group-yourself" action in Russian, with a picture: