I just came across this exercise suggested for seniors to build muscle strength in the arms and shoulders. It seems easy, so I thought I'd pass it on to some of my friends. 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 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. After you feel confident at that level, put a potato in each of the sacks; but be careful.