In the gym, there's always time to show off! Making comparisons with your former self, maybe; flexing with friends all hoping to be the 'best'... so get the cameras ready:   And encouragement to the young generation who are already developing their sporting capabilities:  

Latissimus dorsi - responsible for those sought-after 'wings' in serious bodybuilders. Consider too trapezius, rhomboid and those small muscles which comprise the rotator cuff. Also in a back view, we can admire the development of the rear and side deltoids.  We commend the increasing tendency for more and more fit guys to post their back views as well as chest and abs in normal 'flexing'. So let's be inspired to work harder on the bits we have to stand between two mirrors to see!    The last word goes to the young 'uns, as usual!