I think it comes down to string tension, and more importantly, the inherent "give" or "play" that any kind of floating trem is going to have.
Compare it to running on asphalt versus running on sand. The sand has more "give", so it kinda absorbs each footstep more readily than, certainly, the asphalt would. So, it's going to take more muscle (so to speak) to achieve the same speed and efficiency under those circumstances.
Transpose that fairly literally to a floating trem versus a fixed bridge. Same idea. At least, that's what my understanding of physics (albeit somewhat limited) wants me to think.

Anyone care to add to that?
EDIT: oh, and the "type" (i.e. "model") of trem probably won't matter too much, inherently, as much as things like overall string tension and more importantly SPRING tension would. I think the core physics will apply to just about any trem system with fairly predictable results.