Pretty much all has been said here by somebody or other. Here's what I have done to work up to 85#'s. I do have several bows from mid 60's to the 85# so I don't try and do it all at once, but I could if I wanted to. I keep the heavy bow strung all the time, right where I will see it and whenever I notice it, I will draw and hold it as far back as a can, without forcing it, yanking it back, is a sure way to hurt yourself. Even when I get to the point where I can draw and hold it at full draw for 10-15 seconds, I will stop at 1/3 and 2/3rd's draw and hold it there for 10-15 seconds. After I do that as many times as I can without forcing it, I switch hands and do the same thing left handed. You are much less likely to have problems if you develop both sides equally AND you will develop faster, since ANY exercise helps the whole body, hench crosstraining. When I start out, I only draw the bow every third day at most. Exercise dosn't build muscles it tears them down, BUT when they rebuild they rebuild stronger, but it takes about 72 hours for that to happen. After the muscles get built up where you can shoot the heavier bow, I shoot it almost everyday, but not to the point where I am having a hard time drawing it and if the muscle hurt the next day or day after, I go run up and down the mountain or do some situps or some other exercise not involving my arms. After a couple months, I can draw and hold 85#'s with out any trouble, both right and left handed 10 or more times in a row.