I think it's called a Crosstrainer.
I tried running but realized quickly I will need new knees by the time I'm 40 if I keep doing that.
I just don't have the motor skills to propel myself forward with speed without turning into an elephant stomping around with every step.
I prefer biking and crosstrainer because of that.
I used to have a bike too, but it was so uncomfortable and it hurt my back. I think I used it twice and then I got rid of it :P