Originally Posted by Gallium
It isn't? If you don't have legs, I would have to agree, but if you have legs, and can walk, one of the metrics for fitness is your resting heart rate, and your ability to get to 85% over that rate, and your O2 perfusion.
What you got that is going to do that apart from moving your limbs faster than you normally do to increase your respiratory rate, stroke volume and heart rate (and no, sex aint it....
"Running" in the traditional sense will get you fit, but it's a pretty inefficient way of doing it. Interval sprints, hill runs, and other high intensity stuff will get you in better shape in less time, and it will take off the fat without taking off muscle, too.