Tony Horton’s “P90” system and its variants (X, etc) is awesome
We work out at the same gym and he has invited me to join him, but I am a lot older and my joints ain't what the used to be.
I stick with my rowing machine for cardio and stick with weights (20-30 lbs) for keeping my muscles in shape.
Sit-Rep beat me. I find Tim Horton's system good for my "system." :-)