I shot a High Country Bow that was a horse, old , strong , and really out of date , but it did bring meat home. I used fingers and copper pin sight's . All I can say is lower the poundage and have fun. Check strings for fraying to be safe . As far as future goes, try a release, string loop round pin gaurd on your site and a peep that divides string into 2 parts not 3. These up to date parts really help in accuracy and confidence.
Cant really help with the exercise's , but I have an article on low poundage compounds for folks that have to take care of their shoulders. 60 pounds is usually good enough for most med size game. .
Found it . The mag is called "Bow and Arrow Hunting(.com). June 2006 Volume 44 No.5. If you cant find it let me know , I'll highlight its main idea's if you like.
Welcome back to the world of bow hunting.