Here are just a few moves of what I do with the P90X plyometrics. It's a great leg and cardio workout!
Lately my knees and hips have been killing me from all the running that I've been doing outside. If you turn up the volume you can actually hear just how much my knees and hips pop. This is why it's so important to try and land gently when jumping. My joints have never hurt me after plyo... Just running!