Please choose the correct ending to complete the given sentence: Sports and Fitness: [header] How to tone up your legs [title] Do squats. [step] Squats are a fundamental leg exercise that can be done at home, and is an important exercise to learn before using leg machines at the gym. Once you've mastered the movements, you can add weights to make it more difficult.

Ending1: [substeps] To get into a squat, stand with your feet a hip-width apart. Bend your knees at 90 ° on the inside and center of your body. Ending2: [substeps] Stand with your feet a little wider than shoulder-width apart. Your hips, knees, and ankles should all be in alignment. Ending3: Squats also target the joints, making it easier to move around while also helping to improve endurance and muscle development. [substeps] Sit on a chair or on a small step stool. Ending4: [substeps] Lie on your back on the floor with your arms at your sides with your palms facing you. Bend your knees and if you're using leg machines at a gym, stand on both legs.

Answer format: ending1/ending2/ending3/ending4