Koko Bow,
Bowfit, is, in my humble opinion, the best thing since sliced bread.
Last spring, I sustained an arm and shoulder injury while on professional training. I found, to my horror, that I could not pull my bow. Period. The motion was painful and the strength was not there. Pretty disheartening.
Anyhow, I got the bowfit as a last ditch stand and started working out with it a few times a day. Maybe 5 minutes per session. Initially, there was a bit of pain to slog through but after a few days I got my strength back and after a few weeks, no pain whatsoever. After that, I was pulling my bow again no problem.
I swear by this device. It is worth its weight in gold. And no, I do not get a commission! When I find something good, I like to tell folks about it. You can adjust the weight of the pull simply by doubling up the cord. It is simple and extremely effective.
Hope this helps you out.
Robert