Use a dumb bell weight or a full gallon jug. Put one weight in both hands and put your hands straight up. (not one weight in each hand, one weight total, both hands on it) Then bend your elbows so your hands go behind your head. You need to keep your head up, neck and back straight and knees slightly bend with your feet about shoulder width apart. When you bend your elbows, your hands should go behind your head to the base of your neck. Then straighten your elbows and repeat. Hope this one works for you.