Sit on a flat bench. Grasp a dumbbell in each hand. Your hands are lowered down and the elbows are close to the torso. This will be your starting position.
Exhaling, curl the dumbbells while contracting the biceps. Hold the upper arm (from elbow to shoulder) stationary. Only the forearms should move. Continue the movement until your biceps are fully contracted and the dumbbells are at shoulder level. Make a brief pause as you squeeze your muscles.
Slowly lower the dumbbells back to starting position as you inhale.