This was the workout for the morning and I am beyond thrilled that I was able to do it with the following modifications: On the Jump, Side, Turn and Tuck, I instead did the thing where you have one foot on the step and do like a box jump. Front, side, back side. I think Cathe does them in Strong and Sweaty Boot Camp too. On the Fast Feet Shuffle, I do them facing the step instead of straddling the step and on the sprawl and jab, I always do the burpee part on the step because its higher and you don't have to go down as far. I was even able to raise the step height to 4 risers per side when the time came. I wore my knee brace and didn't have any twinges or discomfort. So, because I had to self diagnose/treat my knee problem, I don't know if its that my knee has gotten better or if the brace is really helping provide support and stability. Regardless, I'm going to keep using the brace! IMO, HIIT 40/20 is the toughest of Cathe's HIIT workouts. For some reason, the double leg lateral jump just takes it out of me and even though its the next to the last exercise, I always have to take a longer break before the wide jumps on the step. It felt good because that workout packs a lot of intensity into just 30 minutes.