The Dumbbell Pull Over is a classic exercise that works both the chest and the back, making it one of the most versatile single-dumbbell movements. To perform, lie flat on a bench with your feet planted and hold one dumbbell securely with both hands above your chest. With a slight bend in your elbows, slowly lower the dumbbell in an arc behind your head until you feel a deep stretch in your chest and lats. Pull the weight back up over your chest, engaging the chest and lats to complete the rep. This move not only develops upper-body strength but also improves rib cage expansion, shoulder mobility, and posture. Depending on your form, you can emphasize more chest or more back recruitment.