You mean people left during the class?
Jumping jacks can be hard on knees too. I do "half jacks" anytime jumping jacks Re offered as an exercise (alternating the legs).
I've seen people get up and leave during classes that they don't enjoy, at the Y I go to.
i have cried but never left :)
Yes, people who are used to the regular instructor, Karen, who is off for a few weeks, didn't take kindly to Carolyn...
My knees are ok with jumping jacks - just the shoulder from last Sunday's fall. But I think it is improving!