The Standing Dumbbell Cross Body Hammer Curl exercise is a very good way to develop your Brachioradialis muscles. It is extremely simple to perform, simply take one dumbbell in each hand and let them hang by the side of your body in a neutral overhand grip (one where your palms are facing inwards). Working the right dumbbell first of all, bend your right elbow and push the dumbbell towards your left shoulder and back up toward your right shoulder. Then simply move the dumbbell back towards the starting position using the same path. Now try this exercise with your left dumbbell, bending your elbow and moving the dumbbell in a rounded movement towards your right shoulder and then your left shoulder. Repeat as many times as you feel comfortable.