Just thinking through some of the logistics. If Rico had maintained that sort of exercise regimen previously, her body should still be able to handle it, probably much better than Enemoto's. Any difficulty he's having with the routine is likely mental rather than physical. Also, we haven't seen much of their system yet for handling schoolwork. Enemoto theoretically already knows this stuff; is he tutoring Rico in the evening? Is she doing the school homework while he's doing the work homework? If they're hoping to switch back at some point, it wouldn't be in her interests to have her not be prepared for quizzes or exams.