Taking pride and pleasure in one’s ability to endure pain is certainly a trait that exists, but not a universal one. It would very surprising for someone who does not share this affinity to engage in regular, focused, deliberate practice at doing work whose sole purpose is its vigorous unpleasantness.

Of course there are people who have pleasant and unchallenging movement as part of their daily life (I walk and bike to work on flat ground, for example) but that is a far cry from going to the gym for a serious exercise routine.