- Sit on a flat bench holding a dumbbell in each hand with an underhand grip.
- Keep your back straight and shoulders back.
- Keep your arms fully extended with your elbows close to your sides.
- Rotate your palms so that they are facing in towards you. This is the start position.
- Keeping your upper arms upper arm stationary, start to curl the dumbbells upwards in a smooth arc.
- As you curl the dumbbells upwards rotate your wrists, so that your palms face in towards you at the end of the movement.
- Continue the movement until the dumbbells are at shoulder level and your biceps are fully contracted.
- Hold for a count of one as you squeeze your biceps.
- return to the start position, rotating your wrists back to an underhand grip position.
- Repeat.
This exercise can be performed by alternating between arms.