This is interesting because I have always found plie squats to be very easy, no matter what amount of weight I use doing them, I could do plie squats until the cows come home...and then milk the cow while still doing more plie squats. It must be simple body mechanics...these are 'easier' for some people than other's.
And the plie jacks are no problem either. I wonder if I have Susan Harris to thank for keeping my inner thighs toned. I still do that floor exercise where are sitting on the side of your hip, sort of, both legs extended, bend left knee and place foot on floor, place a dumbbell on right inner thigh and then turn toe/leg 'out' to a sideways position (this is very hard to describe) but anyway, once you're in position, lift that leg. This was The Firm Volume One. Great leg workout in that vhs.