As someone said, for men 99% attraction lies in big boobs.
I'm afraid that I disagree. Studies have been done that have shown that men's eyes invariably notice a woman's eyes, smile, breasts, hair, weight, legs, clothes, bum, height and skin in that order.
Yes, breasts are quite high up (at number three) but that doesn't mean that it's only the large ones which get noticed. I know that my eyes get drawn whether large or small.
Going back to the OP's original question, I think that a PP's interview analogy is quite good. When a man first sees a woman, it's like when a recruiter first sifts through a stack of CVs. Some stand out and are called straight to interview, others get glanced at before being forgotten.
However if you bypass the first sift (so you knew the recruiter in a social capacity and got asked to interview without applying), they get to know you regardless of what their first impression of your CV was. So likewise, at the sports club the men have got to know the OP's personality and an attraction has had a chance to form which there wouldn't have been time for when passing someone in the street or swiping on Tinder - situations where looks are everything.
How confident and relaxed you are also helps, in a sports club you are all having fun together - that builds attraction too.