For those of us getting along in years, here is a little secret for building your arm and shoulder muscles. You might want to adopt this regimen! Three days a week works well. Begin by standing outside behind the house 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. If you can reach a full minute, relax. After a few weeks, move up to 10-LB. potato sacks and 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, start putting a couple of potatoes in each of the sacks, but be careful not to overdo it.