I agree with you Healthy Outdoorsman, and nice job on the video. Circuits are a great way to increase work capacity, decrease body fat and maintain muscle mass. I'm also a big proponent of bodyweight exercises. I use both as mainstays of my regimen.
That being said, I have actually brought longer endurance work back into my routine (as noted previously). I'm not a crossfitter but I did spend several years borrowing heavily from their stuff, as well as programing developed for combat athletes. What I learned was that if you continually train yourself for 20-30 minutes of intense work, your body will adapt to exactly that. Eventually I found myself sucking wind when the situation required ongoing endurance for an hour or more. Rob Shaul (of MountainAthlete.com and MilitaryAthlete.com) has addressed this quite well in some of his writing. After looking over his stuff, and looking my own deficiencies straight in the face, I responded by increasing my loads on strength days and increasing my mileage on running days.
Not a knock on circuits at all. I am a huge proponent. Just additional food for thought. Good conversation!

