Take a moment to inspect something just managably heavy at the store. Hold it at arms length and very slowly bring it toward you as if you are having trouble focusing on the fine print on the packaging. Raise it up and slowly turn it as if you are trying to see it in just the right light. Heft it in one hand and then the other.

Stop when your arms begin to tremble and put it back. Do it in various aisles or departments as the opportunity presents itself.

Work your way up the sizes. After you are doing watermelons, tires, and cases of water one-handed, move on to a different exercise regime.