Well, I tried my first kettlebell and heavy club Tabata training yesterday, and boy and I aching for it today.
For those unaware of the Tabata protocol of training, it is essentially a form of interval training, with very specific intervals. It was originally aimed at athletes seeking a gain in anaerobic capacity, but works very well for HIIT training of any kind. The protocol is 20 seconds of max effort work, with 10 seconds of rest, for 4 minutes. In order get your intervals totally accurate, I fully recommend using a gymboss personal timer, and working to the beeps!