Sit at the end of the bench and place one dumbbell in front of you between your legs, resting the dumbbell on the inside of your inner thigh. Keep your legs slightly parted. Starting with your right arm, pick up a light to medium heavy dumbbell and place your right arm on the inside of your leg. Begin with the palm of your hand facing away from your thigh. Keep your arm extended and the dumbbell slightly above the ground. Make sure that your upper arm remains stationary as you contract the biceps and curl the dumbbell toward your opposite-sided pec (chest).
Continue the movement until the dumbbell is at shoulder level. Remember, only the forearm should move. Slowly begin to lower the dumbbell back to its starting position. Always avoid swinging motion during this exercise. Perform all reps using the same arm, then repeat this movement with your other arm.
Perform 4 sets, 10 to 12 reps. Resting approximately 30 to 40 seconds between sets.