Yes it does. As for squats are you going deep enough in your squats?
Lunges are also wonderful, in fact, they are probably more effective than squats. BBL has some isometric type moves that work. I don't consider P90X to be especially high impact although there is impact (jumping jacks, jogging in place, basketball shoots, etc...) but there are modifications and the program still works if a person chooses not to do ANY jumping.