Can health problems be brought up in application?

yes, my transcript shows my mid term grades. my final grades were also pulled down by them to a significant degree - they would have been far, far higher if not.
i’m a national medallist in swimming and i was representing my state for the national games. the times were shifted around because of COVID so it ended up happening during a time where classes were more intensive.
i’m trying to communicate this to my counselor but honestly, i’ve not had much contact with her - and teachers are shuffling around the responsibility of uploading (i’m the one of the only ones applying abroad from my grade). i only knew that my school even had a counselor a few weeks back. my LORs are weak (or will be weak, apart from the additional one) because none of my teachers have a lot of experience writing an LoR (and i had limited options). they do have good comments or attempts at good comments (nothing bad) but it just comes off as generic. i’m not really sure what can be done. hopefully they read the LoR’s in context of the school i attend?