Just came across about some research about estimating the strength of people from photographs showing only their faces. It apparently works pretty well, and works just as well on those who train in the gym, but only when it comes to upper-body strength. Does not work as well on women.
Press release: http://www.ia.ucsb.edu/pa/display.aspx?pkey=1867
Interesting how this implies that being able to accurately estimate a man’s upper-body strength is more important for survival than being able to estimate lower-body strength. That would explain why you’ve got dozens of guys who don’t train legs for every one who doesn’t train chest.
On a related note, there’s also the recent paper about how broad-faced hockey players get more penalty minutes. http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=2570531