 Subconsciously, upper body strength is most correlated with the ability to kill another man. Men before weapons, you remember Homo sapiens about between two and 700,000 years old. So there's many, many thousands of generations of your ancestors. Men killed with their fists, a lot. And so men who had wide shoulders and muscular arms were very powerful. And so if you don't have a good face and you ain't tall, get a strong upper body. It's very attractive to women.