I just think the study has been blown out of all proportion and it is used by people to bash steady state work and say all you need to do for aerobic and anaerobic training is 4 minutes of hard work, which I think distorts the study.
The first thing people tend to forget is that the HIIT group did one session of 30 minutes LSD work a week in addition to the intervals
Secondly to quote the study:
“Average VO2 max in group one was 52.9 (LSD group) in the second group it was 48.2 (HIIT Group)”
So the LSD group had a larger VO2 at the start, so they had a better aerobic system to begin with and would be less likely to see improvements in the 6 weeks
Also whilst the HIIT group saw good increases in VO2 mas in the first 3 weeks, in the second three weeks as tabata himself said “no significant changes were observed."
Whilst the LSD group saw smaller but steady increases over the whole 6 weeks.
So the study proved that HIIT causes better short term adaptations but they stall after a few weeks whilst LSD leads to slower but more steady progress
Also he only tested VO2 max for aerobic fitness, if Tabata had measured other variables such as changes in cardiac output and stroke volume, resting heart rate, anaerobic threshold, velocity at anaerobic threshold, etc. you would have got a different result
I also don’t like how people use tabata for bodyweight stuff, weights etc, the original study used the bike and subjects were very carefully monitored, once pedal speed dropped below a certain point the training was stopped as it was no longer considered beneficial, this is very different from simply trying to work as hard as you think you can doing burpees or running
Overall I think the study was useful but has been blown out of all proportion and used as an excuse not to do LSD work, threshold training or any other longer term aerobic training etc