What exactly is new in fitness? In the exercise world, there's something new in equipment, research, classes, gadgets, videos, and Web sites just about every day. The last few years have also seen the invention and marketing of new schlock--like pills that claim to eliminate cellulite or burn extra carbohydrates and machines that purport to tone your thighs "without any effort on your part." It's all too easy to get confused by all the myths and mixed...