Sit on a flat bench. Take a dumbbell in each hand. Your hands are lowered down and the elbows are close to the torso. Palms are facing inwards. This will be your starting position.
While holding the upper body stationary, curl the weights using your biceps and twisting the wrists so that the palms face forward at the end of the movement. Hold your arms (from shoulders to elbows) stationary. Continue the movement until your biceps are fully contracted and the dumbbells are at shoulder level. Hold the contracted position for a brief pause as you squeeze your biceps.
Inhaling, slowly lower the dumbbells back to the starting position as you rotate the wrists.