Please choose the correct ending to complete the given sentence: Sports and Fitness: [header] How to stretch your knee [title] Use dynamic stretches to strengthen and stretch your muscles. [step] This exercise works your thighs and supports good body mechanics-including how your knee moves-if it's done properly. Start with a smaller range or motion and keep your movements within your pain-free zone.

Ending1: Lie on your back on a mat or a work surface. You'll most likely want to support yourself using a desk chair or bench. Ending2: Here are some dynamic stretches to get you started : [substeps] Sit on the floor with your head low and your feet shoulder width apart. Bring your hands near your mouth (palms facing down), locking your fingers together and pressing them into your middle molars. Ending3: Stand tall with your feet shoulder width apart, and rest your hands on your quads or extend your arms in front of you. Keep your back straight, bend your knees, and lower your hips as if you were sitting in a chair. Ending4: As you stretch, try to roll your knee a few times in a circular motion. This will help to strengthen your hip and thigh muscles, which your knee should move in a specific way.

Answer format: ending1/ending2/ending3/ending4