I've had a nagging knee injury lately, and have not been able to ride my bike as much as I want, so I have given suspension training a try. I bought the Rip 60 suspension strap kit which promises to "fire your core". Sounds a bit idiotic, but after you can figure out how the hell to put the straps up, it tends to work pretty well. I see all kinds of these things popping up now, Lifeline, TRX, Fitdeck, etc. The Rip 60 came with some DVDs and a nutrition guide, so it is supposedly more inclusive, although I've noticed that the price has been dropping with each new product I see. I think they are ok, cheaper than a gym, but I am really itching to get back on the bike.