I've opened a LOT at gyms. I open everywhere. Only issue is if she rejects you or gets a weird vibe then you'll feel weird. I've conditioned myself not to care and I'm friends with the staff usually so it wouldn't matter and most of the regulars at gyms I go to are my friend.
I've gotten either 1 or 2 lays from cold approaches at the gym. Statistically very low. I've gotten countless numbers and "yes" to hanging out and to going on a date, but never managed to get the girls to meet up. So you can do it. But I am also very fit and am clearly there to work out and don't **** around so they can see that I don't talk to people or waste time or socialize, which I am thinking matters, but am guessing.
Being very fit does help though. I look like a small time model. I'm about 20% away from looking like a legit fitness model. Strangers come up and ask me for work out advice or how to look like me. It sucks when they ask about my good abs though, because I don't have an answer to that. It's just genetics for me and I've always had it.
Interesting Note: I'm Asian and asians also have 6 packs, while white guys are known for having bigger arms.
White girls like 6 packs if they like the asian guy and he isn't a passive ***** (most asian guys are this).
Asian girls like white guys because of their bigger arms as most asian guys don't have bigger arms.
This is an observation I've confirmed a lot of times.
My 6 pack just to note isn't a weak one due to being skinny, which is what most Asian guy's 6 packs are from, but girls usually can't distinguish it, and some girls like the very skinny look, I personally don't like or want to be super skinny so I'm never going to be intentionally that.