One of the trainers at my gym has suggested I might want to limit most of my running right now to the treadmill outside of class, that it is easier on my joints until I get a bit more accustomed to it. Is there anything to that? I hate treadmills, they feel so...unnatural. I also can't see how they can be easier in my joints as my feet are still striking a firm surface, but I am ready to be educated.