Hmm ginnifer, I'm not sure! I mainly do them on my knees, but I think if you can manage 1 or 2 proper ones in a batch that's good going. Although I use my knees, I make sure I can feel both my core and my arms being worked. I've always been useless at proper pushups!
Geeklove, Turbofire is a lot of fun and does cover things like core etc. but not really on the same DVDs. JM is more comprehensive in that strength, cardio and abs all gets worked in the same workout (for Shred, Ripped etc.).
Turbofire is a fantastic cardio workout, and actually I guess the core is worked a fair bit with lots of knee raises and standing crunches. What I really like are the HIITs in amongst the workouts - which are 1 minute drills where you go all out cardio, then rest for a minute. HIITs are apparently really effective for calorie burning.
It is very choreographed and it took me quite a few gos to get the hang of it... and it is of course very expensive!
I would say it might be a bit iffy if your knees give you problems, as there is a lot of twisting and jumping.
That's a bit of a vague description but ask me anything else you want to (or wait for CHST to come back from holiday and ask her as she has turbofire too and may well explain it better!)
Didn't fit anything in today but did cycle 6 ish miles very slowly
Need to get some more in before I head off on holiday so am thinking of a double JM session tomorrow, if I can manage it, as I haven't done her stuff in ages!