Levitating during exercise

In one dream this morning, which included irrelevant parts about things like getting my laptop computer back from somewhere, I was upstairs exercising on something like a cross-trainer, except it sometimes looked more like an old garden roller. When I was getting settled on it in a good rhythm, it would inconveniently levitate, just a little, no more than a couple of feet. This was awkward because it would float around a bit, sometimes such that other things in the room would get in the way of my trying to use it. As I used it, I puzzled over the phenomenon, not seeing how me on heavy equipment could be lifting from the floor.