Begin by standing on a comfortable surface, where you have plenty  of  room at each side.

With a 5-lb potato sack in each hand, extend your arms straight out  from your sides and hold them there as long as you can.

Try to reach a full minute, and then relax.

Each day, you'll find that you can hold this position for just a  bit longer.

After a couple of weeks, move up to 10-lb potato sacks; then try 50- lb potato sacks and then eventually try to get to where you can  lift a 100-lb potato sack in each hand and hold your arms straight  for more than a full minute. (I'm at this level right now.)

After you feel confident at that level, put a potato in each of the  sacks.