High-intensity interval training (HIIT) is an advanced form of interval training. An exercise scheme with interchanging periods of short intense anaerobic exercise with less-intense recovery periods. HIIT is a form of cardiovascular exercise. Normal HIIT sessions may vary from 4–30 minutes. These short, intense workouts provide improved athletic conditioning, improved metabolism and improved fat burning.
HIIT training is a popular form of cardiovascular exercise when it comes to intervals based sports e.g. football, basketball, rugby etc.
A HIIT session often consists of a warm up period of your chosen exercise, followed by 3-10 repetitions of high intensity exercise with medium/low intensity exercise in between. Ending with a cool down period. The high intensity intervals should be done at near maximum intensity with the medium exercise being around 50% of your maximum intensity. There are no set time periods for HIIT training. A popular time frame is 30 seconds of sprinting followed by 15 seconds of jogging/walking.
A popular form of HIIT training is Tabata. Tabata training was initially used for Olympic speed skaters. It consists of 20 seconds of ultra-intense exercise followed by 10 seconds of complete rest.This is often completed over a 4 minute period which would consist of 8 cycles.