Superman

...or Superwoman as the case may be. Ever wonder how he stood so straight with hands on hips, stretching the S accross his manly chest dripping with... ahem.. I mean, posture was perfect right? It's all that flying I tell ya - believe me, working the upper back will give you the upright stance of superheros:

Muscles Worked: Upper back
Time to Complete: 6-8 minutes
You will need: LIGHT dumbells (2-4 lbs) and a small towel

1. To start, lay on the floor with stomach side down; place a rolled up towel under your forehead so you can breathe (very important!)
2. Grab both dumbbells and extend your arms fully overhead (Superman position)
3. Slowly, without moving your legs, core, or head - raise your arms while keeping them straight - hold 2 pulses then release down (the total movement is small, about 15-20 degrees)
4. Perform a total of 10 reps, rest 30 seconds then repeat for 2 more sets

You can also do this with your arms in a "T" shape out the the sides.