Instructions:

1. Stand with your feet shoulder-width apart, holding a dumbbell in one hand at shoulder height with your palm facing inwards.
2. Engage your core and keep your back straight.
3. Press the dumbbell upwards until your arm is fully extended.
4. Pause for a moment at the top, then slowly lower the dumbbell back to the starting position.
5. Repeat for the desired number of repetitions, then switch to the other arm.