Why High Intensity Interval Training works so well HIIT

High Intensity Interval Training (HIIT) is a training program that utilizes short intense nearly max effort exercise, followed by a reduction in intensity recovery period. There are several different methods to the exercise method.

Sebastian Coe 2 time Olympic Gold Medalist

The first introduction of a form interval training was by Peter Coe. Peter Coe was the track coach of the famous Olympian Sebastian Coe. In these sessions Peter would have his son run 200M as fast as possible, then rest for 30 seconds, then repeat. VO2 max is the maximum amount a person's muscles can transport and use blood during incremental workouts. A person's VO2 max is indicative of their total personal fitness. This pushes the body beyond its VO2 max for short periods of time, then allows a short recovery to get some oxygen back to the muscle tissue just long enough to recover for the next intense effort. Using this method Sebastian Coe was able to win several Olympic medals including the gold in 1980 and 1984.
By pushing the body past the VO2 threshold for short periods of time this increases the VO2 threshold which as earlier discussed is indicative of total personal fitness.

Professor Izumi Tabata Perfecting his Method

Professor Izumi Tabata improved on the HIIT by introducing the Tabata method. This involves 20 seconds of Ultra intense exercise at about 170% VO2 Max, followed by 10 seconds of rest, completing this circuit 8 times for a total of 4 minutes of exercise. Using this method 3 times a week an already fit athlete can expect to see increases of about 2% in as little as 7 weeks.
So great right? Thanks for the history lesson, how does this help me? There are numerous different training programs out there that have a HIIT backbone as their structure. Bootcamp for instance, but probably the most well known would be CrossFit. CrossFit is essentially a well disguised version of HIIT with better marketing. And by better I mean HIIT doesnt have any marketing while CrossFit is sponsored by Reebok.

CrossFit does have remarkable results

This is why CrossFit has the amazing results that people find, whether it be from increased strength or balance, most CrossFit gyms or "boxes" as they are called have an atmosphere that lends itself to a social setting in which people all work out together at the same time each day, reach personal bests, for friendships and encourage each other, because of the great results and the fast friends formed, it becomes "addicting"
It amuses me to hear a CrossFitter say something to someone that has never done CrossFit like, "you wouldn't understand, it's a CrossFit thing" Ironically the CrossFitter does not understand it is a HIIT thing. But then again I tend to think most CrossFitters are meatheads. At least my friends are at my local box. Enjoy your WODs (Work Out of the Day)