[Seeing Leon reminds Hijikata that he plans on training with his pokémon later (it's not like he has any regular pets); he looks forward to that. But right now, Rinku's single-mindedness reminds him of himself when he was still a kid.]

If you keep training, you'll keep getting stronger, but don't push yourself past your breaking point. That'll only take you out of commission and benefit no one. I'm sure Evangeline tells you that too. Also remember to do some fun things as well. You can't let "getting stronger" become your whole life.

[Again, he's been there and it wasn't a good place to be in!]