A push-up is a popular exercise that helps strengthen the muscles in your arms, chest, and core. To perform a push-up, you start in a plank position with your hands placed slightly wider than shoulder-width apart. As you lower your body towards the ground by bending your elbows, you keep your back straight and your feet together. Then, you push back up to the starting position. This exercise can be modified for different fitness levels. For beginners, doing push-ups on your knees can make it easier, while more advanced individuals can try variations like the clap push-up or diamond push-up for added challenge.