Tabata intervals consist of 20 seconds of maximum intensity exercise, followed by 10 seconds of rest. The cycle is repeated 8 times (= 4 minutes). Tabata protocol can be applied almost to any exercise, but its recommend to use an exercise that activates alot of muscles. Tabata method is very demanding and you should consult your doctor before beginning tabata interval training.
Studie that shows the effectiveness of Tabata training:
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.