What is Interval Training?
Interval training on a turbo trainer is a series of specified intensive exercises for short periods of time with recovery periods in between. The objective is to raise your Lactate Threshold so that you can ride harder for longer thus improving your speed and endurance.
Usually in world of turbo training the length of intervals are based on specific times whereas out on the road they can be based on specific stretches of road identified by certain features such as lamp posts, signs, climbs etc.. This is usually called Fartlek training.
Recent research has found that High Intensity Interval Training (HIIT) where short intervals of maximum efforts with very easy recovery periods in between, have resulted in improvements in endurance. However these put the body under a lot of stress as the efforts are close to, or above, the anaerobic threshold.
The recovery periods are done at endurance pace or below. They are ideal for turbo training as a HIIT session need last only 45 minutes.
How High Intensity Training works
The intense efforts use the anaerobic system which produces an excess of lactic acid. During the recovery interval the body uses oxygen to re-process the lactic acid for further energy production and in this way the Aerobic system is developed. Over time the body will become more efficient at using oxygen to deal with the lactic acid and will be able to exercise for longer at a higher intensity thus reducing the rate of fatigue and muscular pain.