I love 30 Day Shred but it wrecks my knees :(. I've tried everything - modifying the high impact parts of it, wearing supports on my knees etc etc but they just can't hack it.
So, I'm looking for something equally tough on the rest of my body but much, much gentler on my poor old knees - any recommendations? If it helps, it's mainly my abs and thighs that I need to work on.