Please choose the correct ending to complete the given sentence: Youth: [header] How to do a knee flip on a trampoline [title] Allow your experience with front flips to act as a guide. [step] Before you jump, warm up by doing some stretches. Then start to bounce on the trampoline as you do when you attempt front flips.

Ending1: See how far you can jump without discomfort after your first bounce. This part of the exercise is essentially the same as a front flip. Ending2: [substeps] Gain as much air as you can as you bounce on top of the trampoline. Repeat your jumps at least a handful of times to ensure you're getting the most air possible for your flip. Ending3: Practicing these stretches will help you bounce between forward and backward turns. [substeps] Have some backbends and a couple of handstands that require focusing on your weight instead of jumping. Ending4: [title] Land with your feet hip-width apart. [step] Once you are stretched and balance, land with your feet and buttocks on the trampoline.

Answer format: ending1/ending2/ending3/ending4