What you must do: Lengthened on the glutei and the bottom of the back, the legs tended, the hands behind the head and the top of the separated back of the ground.
While contracting your abdominal muscles and while keeping the bust in the same position, bring back your knees in the direction of the chest by keeping the tended legs, then return to the starting position.
Breathing: by carrying out this exercise expire (to empty the lungs) when bring back your knees in the direction of the chest and inspire (to inflate the lungs) when return to the starting position.
