Exercise for over 40s

I came across this exercise suggested for the over 40's to build muscle strength in the arms and shoulders.

The article suggested doing it three days a week.

1. Begin by standing on a comfortable, flat surface, where you have plenty of room at each side. With a 1kg potato bag in each hand, extend your arms straight out from your sides and hold them there as long as you can. Try to hold for a full minute, then relax.

2. Each day, you'll find that you can hold this position for just a bit longer.

After a couple of weeks, move up to 5kg potato bag. Then a 7kg potato bag and eventually try to get to where you can lift a 10kg potato bag in each hand and hold your arms straight for more than a full minute.

(I'm at this level).

3. When you feel confident at that level, put a potato in each of the bags.