Stand with a dumbbell in each hand at arm’s length and the palms facing each other. Curl the weights up in front of yourself, rotating the hands so the palms face up and toward you at the top, then lower under control, rotating the hands again until the palms face each other at the bottom.
 
Purpose
The supinating dumbbell curl is a simple exercise to strengthen the biceps and help achieve or preserve symmetry side to side. It’s also helpful for strengthening the elbow joint. Using dumbbells allows the hand and wrist to be in a comfortable position and prevents potential strain at elbows common when curling on a barbell. The supinating motion adds a rotation element to the elbow and increases the contribution of the forearm.
 
Programming
Generally sets of 6-15 reps are appropriate.