"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." -from random site about Tabata, Google search.
Other source:
"Tabata Training was developed by Izumi Tabata (imagine that) at the National Institute of Fitness and Sports in Tokyo, Japan. They did a study on comparing the effects of moderate intensity endurance(aerobics) and high endurance intermittent training(tabata training intervals) on VO2 max and anerobic capacity.
To cut to the results of the study: the moderate intensity group training program produced a significant increase in VO2 max of about 10%, but had no effect on anaerobic capacity. The high intensity group improved their VO2 max by about 14% while anaerobic capacity improved by 28%. The study was done over a six week period. Both groups working out 5 days per week."
It seems very good for endurance, but my guess is that the explosiveness in the exercise should also help build bigger muscles.
(the anaerobic muscle types)
I have no scientific data to base this upon, just deduction from what I learned while in school.
But based on what I could find on the web, it seems good both for building muscle and for endurance. (probably not
the most effective for building huge muscles, but for a composite muscle mass with a combination of endurance and explosive strength. Which theoretically should be far more attractive than the largest muscles (also according to the women I've discussed this with) considering the whole biological attraction theory (e.g. the stuff Gunwitch goes through in "Gunwitch Method 2":
http://www.gunwitch.com/seduction/gwm2.html )
