Simulating the Butterfly Stroke?

Butterfly stroke does broaden your shoulders but it takes a lot longer if your over say 22-24. The weights sounds like it should work, but it won't work as well as actual butterfly stroke. Doing the stroke would take twice as long as someone say, 25, and then add the fact that you're not doing actual butterfly, it will take you four times as long to work your shoulders as a younger person. Basically, Your bones have really slowed down growing, and are becoming brittle, so it's a lot harder to make the bone stretch and grow to broaden your shoulders. It will take four months to broaden as much as a younger person in one month. Hope this helps.