I must say these workouts are really challenging. I though my leg were very strong. I do at least 2 Cathe Leg workouts a week, plus running and step. These workout are really targeting deep in my glut muscles. I have never have pain like this ever! I can't even sit down, lol. I am trying to figure out which exercise is doing it and I think it may be the lunges using the dixie cups. Wow, this is a great series, I'm loving it! I love all the new push up sequences as well, very challenging.