Biologically, men strive for a durable, toned physical figure to impress women in order to show they are the "healthiest" out of the others to reproduce with them, of course. Now, talking philosophically, why do men want physical strength when we've adapted from being unintelligent to sophisticated? I believe in order to not die from ideals and beliefs, men "muscle up" to stop those who are still ignorant from killing the intelligent/wise who cannot stand up to intellect and feel they must hurt to feel right and/or in power.
This is anti-socratic and it's just a theory to go a little deeper into biology and make it more philosophical.
You make a good point, janesix. Now that I've reread it, I realized it's still biological. It's philosophical, but mainly biological because it has to do with survival, and being physically stronger has to do with exactly that. Very insightful.