Your wrist, your fingers, and your hands are all very delicate. You must have an equal balance between the muscles responsible for flexing and extending the wrist, or you could be headed for injury. There are several exercises you can use to strengthen your wrists by using progressive resistance. One such group of exercises uses the Ultra Toner Tube^TM and includes resistance wrist curls, as demonstrated by professional fitness trainer Roberta Bergman, M.S. (see illustrations at left).