I doubt the correlation is all that strong, if it exists at all. What's attractive to one person isn't attractive to another. There might be a sub-cult of women who go for muscular men, but it's probably an awful lot of work to become muscular, and then there's the problem of finding this sub-cult of admirers. Meanwhile the women who don't go for muscles lose interest in you, so it's like playing reggae instead of folk music - you'll just get the attention of a different set of fans but the numbers probably won't change much.
And there are so many other parameters, many that can't be altered.
I used to believe in the importance of some kind of "global attractiveness" that would have girls beating a path to my door, but gradually I started to think that compatibility was a lot more important. There might be something in the looks thing for people interested in one-night stands, but even then I think a lot depends on the taste of the individual woman. People aren't just a homogenous bunch of clones. Each person has their own preferences. Everybody has their own hopes and fears.
When I was in circulation I began to focus mostly on personality - both my own and theirs. I became more successful with women when I started to do that. It was a lot more about what I did than how I looked. And it seemed to me that when a woman liked me it was because I liked her - for better reasons that just wanting a girlfriend - and wasn't afraid to show that. Being cheerful, confident, and positive helped, but those qualities don't come to order very easily. Fake them at your peril unless you don't care what happens tomorrow.