I thought id let y'all in on a little secret I've found for building up my arm and shoulder muscles. If you adopt this regimen, 3 days a week works well.Ok so I start by standing outside behind my house and, with a 5 pound potato sack in each hand, extend my arms straight out to my sides and hold them there as long as I can. After a few weeks I moved up to 10 pound potato sacks, then 50 pound potato sacks, then finally I got to where I could hold 100 pound potato sacks in each hand and hold my arms straight out for more than a minute. Next, I started putting a few potatoes in the sacks, but I would caution you not to overdo it at this level.??