It's pretty clear that "forced" in the context of the experiment is being physically forced to do more work, not being "forced" like being forced to eat your ve

It's pretty clear that "forced" in the context of the experiment is being physically forced to do more work, not being "forced" like being forced to eat your vegetables. I think it has something to do with external energy being added, and the subject not having control over the speed.. I don't know if a treadmill really meets this criteria. I think you would have to be physically strapped into the treadmill :P