Please choose the correct ending to complete the given sentence: Sports and Fitness: [header] How to do a supine overhead stretch with an exercise ball [title] Set your exercise ball in a vacated area. [step] Make sure you are securely planted on the ball before proceeding. [title] Lie down with your back against the ground and your legs straightened out in front of you with one leg on either side of the exercise ball.

Ending1: [step] Squeeze the ball by bringing your calves closer together as you rest your arms at your sides. Tighten your abs and relax your head and neck, pressing your lower back into the ground. Ending2: [title] Pinch your toes and arch your back slightly so your toes are almost touching. [step] Bend forward slightly towards the ground until your tailbone is touching the ground and your arms are straight. Ending3: [title] Push down the ball with your non-dominant foot. [step] If your foot still has the ball in it, put out one leg and bring it to the ground. Ending4: [step] Your foot should be placed directly on the ball, with your knee bent to give you the greatest amount of traction. [title] Make sure you have a towel or non-slip mat under you to secure yourself.

Answer format: ending1/ending2/ending3/ending4