Please choose the correct ending to complete the given sentence: Sports and Fitness: [header] How to warm up with an exercise ball [title] Consider the amount of space being left when resting your exercise ball down. [title] Sit down on the exercise ball with your legs in front of you, knees bent and feet on the ground. [step] Walk yourself forward slightly if you're not comfortable, but don't fully lean back against the ball.

Ending1: With your arms resting at your sides you should now be in a neutral position. [title] Spread your legs further apart from each other to stabilize yourself. Ending2: [substeps] You may need an adjustable chair or step stool to exercise the ball comfortably. [title] Lift your arms into the air until they reach a point just behind your back. Ending3: [title] Get into a down position with your feet shoulder-width apart on the exercise ball. [title] Bend your knees in front of you, resting your hands on the balls of your feet, for warmth. Ending4: [title] Gently move your feet forward towards the ends of the balls. [step] Keep your right foot about parallel to the outside of the ball, so that you're not leaning forward.

Answer format: ending1/ending2/ending3/ending4