Dumbbell Tricep Kickback
Stand along side a flat bench. Place your right knee on the bench, lean forward and place your right hand on the bench to help stabilize you. Have your left foot on the floor. Keep your back straight and midsection firm.
With a dumbbell in your left hand, bend your left arm and bring your elbow up to your side so your elbow is in line with your back or slightly higher.
Keeping your elbow pivoted at that point extend your forearm out behind you until your left arm is nearly straight. Then lower your dumbbell to starting position keeping your elbow pivoted in the same position. Repeat to complete your set, then swap sides.