Please choose the correct ending to complete the given sentence: Sports and Fitness: [header] How to do a burpee [title] Begin in a standing position. [step] Your feet should be shoulder-width apart. Now, lower your body into a squatting position, placing your hands on the floor in front of you.

Ending1: [substeps] At first, your knees should be directly under your hips, as opposed to sitting cross-legged. This will prevent your knees from getting too close to your pelvis. Ending2: [substeps] Press hard and raise your arms overhead. Walk your feet to about shoulder-width apart. Ending3: [title] Kick your feet back so that you are in push-up position. [step] Beginners or those uncomfortable kicking their feet back can walk back into the pushup position. Ending4: Your center of balance should be between your feet and your belly button (if you have one). Keep your feet about hip-width apart and your knees perpendicular to the floor.

Answer format: ending1/ending2/ending3/ending4