Thanks, I'll have to keep an eye out for that book. For the record I'd give you a cc if I could. When you do talk more about this would you also address whether there is more benefit to skipping at different points in your workout (before, during or after) and whether there are drawbacks to doing long sessions rather than short with breaks. I wouldn't think the interval principal would be a factor since you have to keep going the whole time and can't vary the intensity all that much...beyond a certain point anyway. Maybe I'm wrong about the intensity though. I used to skip as part of my warmups but now i'm at a new gym and they rarely have us do it so I usually just do a 10 minute session after the coaches finish with us.