A simple google search of the name “tabata” results in many articles about the tabata sequence.  Below is the one of them:

The Tabata protocol is a high-intensity training regimen that produces remarkable results. A Tabata workout (also called a Tabata sequence) is an interval training cycle of 20 seconds of maximum intensity exercise, followed by 10 seconds of rest, repeated without pause 8 times for a total of four minutes. 

Credit for this simple and powerful training method belongs to its namesake, Dr. Izumi Tabata and a team of researchers from the National Institute of Fitness and Sports in Tokyo, Japan. Their groundbreaking 1996 study, published in the journal Medicine and Science in Sports & Exercise, provided documented evidence concerning the dramatic physiological benefits of high-intensity intermittent training. After just 6 weeks of testing, Dr. Tabata noted a 28% increase in anaerobic capacity in his subjects, along with a 14% increase in their ability to consume oxygen (V02Max). These results were witnessed in already physically fit athletes. The conclusion was that just four minutes of Tabata interval training could do more to boost aerobic and anaerobic capacity than an hour of endurance exercise.

The workout for today was two 1 mile repeats followed by a four minute tabata sequence of sprinting.  The miles were to be run at about 5K race pace with a 400 meter recovery jog between them.  The tabata would follow after that.  We broke up into two groups for the miles.  The first group would run between 5:30-5:40 and the second between 6:00-6:10.  The 6:00 group started first and the other group followed about 100m behind.  Bill took the second group through in near perfect pace.  For me, it felt way too fast.  The first 200 I thought was too hard and ended up being a second slow because I had backed off a touch.  I quickly adjusted pace and got back on track.  The rest of the mile went systematically according to plan.  We (Bill, Terry, Rich and I) finished in 5:34.  I was surprised we ran that fast.  It didn’t seem all that tough.  The next mile would tell the tale.  After only a lap of recovery we were started again in the same fashion as the first.  This mile started out a little bit quicker but very much controlled.  Our splits were very consistent and again we all finished in exactly 5:34 for the second mile.  It hurt quite a bit more than the first one, but I was surprised we were able to hit it perfectly.  Another recovery lap and we were deciphering this tabata workout.  Terry gave us the low-down.  20 seconds of all out effort (i.e. sprinting on the track) with 10 seconds recovery [eight times] for a total of four minutes.  Once we started, the first two or three were not that bad.  But then the rest of them started to drag on.  I was completely anaerobic and praying for more rest.  Once the timer went off to start to recover, it took a few seconds to actually come to a stop.  By that time you had 7 seconds until the next all-out effort.  It hurt.  I’m not sure if I’ll notice a 14% increase in my VO2 max, but any improvement is welcome.