I came across this exercise suggested for recoverees, to
build muscle strength in the arms and shoulders. It seems so
easy, so I thought I'd pass it on. The article suggested
doing it three days a week.
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, 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
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.
Once you feel confident at that level, put a potato in
each
of the sacks.