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!  

...should be doing this most days of the week, actually...   Indeed. Let's focus on the training from here on, rather than the sweat! We'll finish with a salute to the kids who REALLY want it - 12yo Logan first: Then a 13yo...  Ibrohim in Uzbechistan like his battle ropes: