A popular regimen based on a 1996 study uses 20 seconds of ultra-intense exercise (at 170% of VO2max) followed by 10 seconds of rest, repeated continuously for 4 minutes (8 cycles). In the original study, athletes using this method trained 4 times per week, plus another day of steady-state training, and obtained gains similar to a group of athletes who did steady state (70% VO2max) training 5 times per week. The steady state group had a higher VO2max at the end (from 52 to 57 ml/kg/min), but the tabata group had started lower and gained more overall (from 48 to 55 ml/kg/min). Also, only the Tabata group had gained anaerobic capacity benefits.
On Monday, I tried and could only go up to 4 cycles before I could go at maximum intensity no more. On Wednesday, I tried again and this time I made it to 5 cycles before saying "Na mas". It is quite incredible how exhausting even 120 seconds of high intensity exercise can be. The main thing is to be able to go at high intensity for all cycles. The moment you feel yourself faltering is the time to stop. I'm going to keep at this for a while to see what benefits follow.