I enjoyed the article Cord, I wouldn't agree with everything, but there was a lot of very good info in there. I particularly liked the advice on sprinting and the sled stuff. However, I'm sure that HIT is just as effective as calisthenics in circuits for high intesity endurance. It certainly seems like a great way of doing things if you like the great outdoors, however I certainly don't have enough space for a nice big tyre in my back garden. Still I see where the chaps coming from: the irregular shapes require a far more "total body" apoproach to lifting.