Please choose the correct ending to complete the given sentence: Sports and Fitness: [header] How to keep your heels down while jumping [title] Go outside, and place a small object on the ground. [step] A grape, blueberry or piece of foam will work for this. [title] Start jumping.

Ending1: [step] Just as you would when you jump off a hurdle, jump over your shoulder for some extra stability. [title] Lower yourself as high as you can and stop jumping. Ending2: [step] Try to jump as high as you can on the jump rope and be careful if you think you may fall. Stop dancing/jumping when you hear a sound like brakes. Ending3: [step] Each time, look down and try to squish or touch your heels to the object. [title] Jump-and-touch ten times in a row. Ending4: [step] Try kicking your heels up as high as they can go before letting them down. If your heels touch the ground make sure to press them back down and build up more breath.

Answer format: ending1/ending2/ending3/ending4