OK, this is how I feel after level 3 of 30 day shred!!! OMG! Ever done walking push ups?? WOW. This level has quite a bit more impact moves, and more activities done on your knees. My knees were screaming b/c I have popped both of them out of joint before, so this level was a bit too much for them. I finished level 3 but I must say I'm more ticked off than happy I worked out. Not because I couldn't do it physically, but because I was frustrated at having to stop 3 or 4 times b/c of my knees. I have some knee pads, so I'll try those next time, but for now, I think I will stick with level 1 and 2. I enjoyed those much more!! Now on to the couch to watch Biggest Loser!!!