My shoulders felt better after the first class and continue to improve. The stiffness is better. I find that I am fairly flexible compared to the others in the class (including the instructor...at least in the activities she has us do), but I have trouble shifting my weight, doing anything with more than one set of body parts at a time...legs and arms, really? And I have very little core strength and upper body strength. I knew about the upper body strength limitations, but I didn't know about the core. Staying upright and walking doesn't really address the core.
Also, I'm worried I'll make my knees worse. I guess I should ask about jumping jacks and knees. There is a woman there who has had knee surgery and I've been watching her adaptations, but she did do some of the jumps so I tried it.