Have you ever tried an eliptical?
I find that they give a much better workout than just flat out running. You can increase the plane of an eliptical so it almost performs like a stepper, or have the plane go all the way down so it's like a treadmill.
And, above all, it's low impact, so not so much pressure on joints and such.
Some people find it's not their bag, espcecially if they are a regular runner and don't want to mess up their stride.
Anyways, Precor has some of the best elipticals on the market. They were the first ones to pioneer the eliptical.
Link
Just an idea to consider!
