I understand how you feel, but I have to admit that my jumping has improved tremendously since I started with Cathe all those years ago. I remember my first workout was Body Max 2, and I couldn't do the two-foot jump onto the step in the power circuits; I stepped up instead. I couldn't do the power turning squats either, and just did uneven squats. Now I can do the entire workout with no problem.
Basically, I just tell myself do what you can, go lower or modify if it feels like you should, and see how it works out. Lowering the step to 1 riser enables me to finish RWH Lower Body Circuit, and I don't feel one bit bad about it. I am at the point now where I am thinking about adding the second riser after the first cardio segment the next time I do it. (I just can't see myself keeping up with the power box followed by the over and over jumping if I have two risers.)
Yesterday I did Cardio Slam, and tomorrow I have Plyo HIIT 2 (I am doing the Strong and Ripped rotation), and I am actually looking forward to the challenge!
Pace yourself, do what feels right, and give yourself credit for your gains... But if you never want to jump, that's ok too!
