This is for older people!!!

Younger people try it at their own risk.
This is working well for me.

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 Three days a week.
Begin by standing straight, 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.

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 a100-LB. potato sack in each hand and hold your arms straight out for more than a full minute.

After you feel confident at that level, start putting a couple of potatoes in the bags.