Hi April,
I agree with everyone else, that Imax will greatly improve your
fitness level. That takes time too, though. I have had Imax for over a year and I just made it through the entire plyo lunge sequence for the first time last week!
Also, I went up to 8 inches for a little while and started having foot and ankle pain. At that point my step instructor told me that I should go back to a lower step height.
So the higher step is not for everone.
By the way, how tall are you? I notice Rhonda stays on a tall step even when Cathe says to go down, but she is very tall. If you are shorter, you may not want to go up.
One more thing, I have found that drinking green tea about an hour before my workout (before I leave work) increases my performance.
Hope this helped!
Cari