Instructions:

1. Sit on a bench with your back straight and feet flat on the ground.
2. Hold a dumbbell with both hands and extend your arms straight up overhead.
3. Bend your elbows and lower the dumbbell behind your head, keeping your upper arms close to your ears.
4. Pause for a moment, then straighten your arms and return to the starting position.
5. Repeat for the desired number of repetitions.