At 5'2" tall and close to 200 lbs, I do not look like an athlete. I love playing many sports that I'm not trained in or good at but enjoyment is most important to someone who doesn't get paid to be an athlete.
My best sport is volleyball. I surely don't look like a "typical" volleyball player - 6'3" tall, slender, muscular. None of those adjectives describe me, so when I walk onto a volleyball court with people who haven't seen me play, the expectation is that I'm not as useful as someone taller, thinner and more muscular. This expectation is rational, I don't have a problem with it, but I find myself intentionally working extra hard to push against it by playing my best and showing that I'm better than I look. This intentional push to prove I'm more athletic than I appear happens on other courts, trails and fields as well.
Honestly, I don't know what other people are thinking of me most of the time, but I assume, without resentment, that people see me as not being an active participant in sports.
A couple of weeks ago I went to a running/specialty shoe store, looking like I do, and was asked by one of the employees, "Do you race in a lot of events around here?" In my mind I answered, "Are you blind? Do I look like someone who runs in a lot of events??"