Please choose the correct ending to complete the given sentence: Computers and Electronics: [header] How to do a single leg squat [title] Sit on a bench, chair, or box that has clear space around it. [step] You start this exercise in the sitting position. You'll be using your chair or box to assist you in performing the squat.

Ending1: [substeps] Your feet should be touching, as this will be the first two touches that you will take or any of the movements of the squat. Your knees will be pressing into the floor as you squat. Ending2: [substeps] Make sure the underside of the seat and the surface of the top of the box is cool to the touch. If it's comfortable to stay in the sitting position for 20 to 30 minutes you are doing the squat. Ending3: [substeps] Make sure to clear all space around your exercise area to avoid injuring yourself or breaking something in your house. Choose a surface that is a little taller than knee height. Ending4: [substeps] Find the' in between' using a wall. You'll almost always find this at the top.

Answer format: ending1/ending2/ending3/ending4