Is this like the manga where we follow the guy who wants to be a side character and the guy he thinks will be a protag is actually a girl in disguise. Yes I'm suggesting the guy we think of as the original male lead could be a girl
Sadly this is what I forsee for this series. Not necessarily the gym stuff but a crippling inferiority complex which keeps him from confessing. Which will add drama and misunderstandings for continued reader interest.