Dumbbell waiter curls are a variation of the bicep curl that focuses on isolating the biceps while also engaging the forearms and grip strength. This exercise is performed by holding a dumbbell vertically with both hands underneath the top plate, mimicking the way a waiter holds a tray.

1. Stand up straight with your feet shoulder-width apart.
2. Hold a dumbbell vertically with both hands underneath the top plate, as if holding a tray.
3. Keep your elbows tucked close to your body.
4. Curl the dumbbell upwards towards your chest, keeping your upper arms stationary.
5. Squeeze your biceps at the top of the movement.
6. Slowly lower the dumbbell back to the starting position.
7. Repeat for the desired number of repetitions.