I would flirt by saying: "ooh a fit girl, might just be my type..." or just connect: "I train too. The feeling after you accomplish a shession is amazing..." , fun: "this covid thing really be shitting on us smhh. You planning on getting back at it?" (perhaps get into a role-play on how you guys get back at it after this text)

But go by your personality, usually there are multiple good texts.

"Well, now that covid's over, you can get back to living ;)"