You may have seen this new exercise machine - a cross between a stepper and a treadmill - at a gym or in a TV commercial. The movement is something like snowshoeing: You keep your feet on the pedals, instead of lifting them up as you do when you walk. Intensity can be adjusted by moving faster or slower, or by setting the resistance of the pedals higher or lower. Because the machines are so new, there hasn't been much research on them - and the findings apply only to the expensive models found in health clubs. But so far the news is very good. Because you don't have to land on your feet, the elliptical walkers are easy on your joints. Despite that, the machines can give you as strenuous a workout as a treadmill. Unfortunately, home models seem to be less smooth and therefore may be more jarring on the joints. So if you're thinking of buying one, be sure to try it to make sure it's really comfortable to use.