I just picked up a bowflex. On my non workout days I want to do cardio. i workout every other day using a bowflex. On my off days I have been speedwalking on the tread mill. I've heard that running isn't that great especially if your trying to build muscle. Should I even be speed walking? Thanks for the help. Matt *Edit* I was just doing some reasearch on circuit training for the bowflex, I bleive it's called HIIT. Can this replace the cardio workout? Also will this interfere with heavy weight lifting? Using this plan I'll be on the bowflex 6 days a week and only on the bowflex.