2. Push-ups

Which muscles are trained: If you do push-ups correctly, you are using your triceps, shoulders, back, and chest, which provides your entire upper body with a workout.

How it’s done: Lie flat on the floor on your chest and stomach. Put your hands next to your chest right under your shoulders. Push up and bring your torso, chest, and thighs off the floor. Keep your abs tight so that your body forms a straight line. Slowly come back down to the floor.