How do you tell if someone has a strong back and shoulders just by looking?

[Cicero]

On p90x it said something about getting a good looking back and shoulders or something how do you tell though?

[senior.2013]

Yes, like the picture where you can tell the muscles from the rest of the body/skin. Its kinda like abs.

[slappy]

good luck with P90 i did it for a bit and it worked great

[Silicate Wielder]

Cool, i can retract my shoulderblades to where they touch but i do feel strong muscles in my back never botherd to see if i have a strong back. my schoulder muscles are increasing in size though.