Kenneth Jay's Viking Warrior Conditioning, dramatic title excepted, is quite possibly one of the best academic studies available on conditioning with kettlebells.

The focus is on VO2max training; the maximum volume of oxygen intake provided by the cardiovascular system. In a nutshell, this is how much oxygen your body can use during activity. The more, the better!

VWC uses the kettlebell snatch as the exercise of choice and provides five progressive protocols for boosting your VO2max capacity.