A strong upper body, wide shoulders, being physically fit and having greater hand-grip strength make men attractive to women, according to a study.
"Evolutionary psychologists have shown that womens mate choices use many cues of mens genetic quality and ability to invest resources in the woman and her offspring," said Aaron Sell from Griffith University in Australia.
"Among our ancestors, one variable that predicted both a mans genetic quality and his ability to invest was the mans formidability. Therefore, modern women should still have mate choice mechanisms that respond to cues of a mans fighting ability," said Sell.
"One crucial component of a mans ability to fight was his upper body strength," he said.
The researchers tested how important physical strength is to mens bodily attractiveness by showing women pictures of mens bodies and asking them how attractive they were.
The results, published in the journal Proceedings of the Royal Society B, showed that it was possible to almost perfectly predict how attractive a mans body is from three things: how physically strong he looks, how tall he is, and how lean he is.
The effect of strength was so large that none of the 150 women in the study preferred weak men.
Furthermore, looking strong was much more important for mans attractiveness than being tall or lean, researchers said.
"The rated strength of a male body accounts for a full 70 per cent of the variance in attractiveness," Sell said.
"The effect of height and weight on attractiveness may indicate that women are responding to cues of health or to the benefits that height and lean bodies have in protracted aggression, hunting and other aspects of fighting ability," he said.
Sell said while the women in their study preferred the strongest bodies, there was a sizeable dataset across many cultures that showed women did not always prefer the strongest looking faces.