High Intensity Interval Training aka HIIT training is all the rage and there are many different HIIT training protocols available, but to produce the best results it is important to understand how to manipulate the Work/Rest Ratio. The Work/Rest Ratio is the ratio of time spent working in the high intensity interval to the time spent in the recovery interval and there is no one ideal Work/Rest Ratio. In fact there are three distinct methods you can use to design interval training programs based on how you manipulate the Work/Rest Ratio.
Fixed Work, Fixed Recovery
This is the most common method and often used for group training because it keeps everyone working together. In this method the amount of time spent in the work phase is fixed as is the amount of time in the recovery phase. For example the ever popular “Tabata” Protocol is a fixed work, fixed recovery protocol using 20 seconds of work and 10 seconds of recovery done 8 times. Another example is the Sprint 8 protocol which uses 30 seconds of work and 90 seconds of recovery. In addition, all MX4 programming uses this method either for a 60/30 work/rest ratio or a 4 to 1 Minute Work to Rest Ratio during Density Workouts.
Needless to say there are endless variations of fixed work, fixed recovery interval protocols and each one feels different and allows for a different level of relative intensity. The advantage of these type of protocols is that they are very simple to design and very easy to track using a simple timer, and if using heart rate monitoring you can adjust the actual work intensity and recovery intensity based on individual heart rate response. Also this is a very easy way for a trainer to manage a group as mentioned previously.
Fixed Work, Variable Recovery
In this method the amount of time spent working
is fixed, but recovery time varies based on heart rate response. This method is a more individualized way to do HIIT training where each work interval begins after the heart rate slows to a predetermined point correlated with a specific level of individual recovery. The advantage of this method is it can be customized to each person based on their goal, age and current fitness level. An example would be doing a 1 minute work interval with a fit 20 year old and setting the recovery threshold at say 120 beats per minute (a relatively low exercise heart rate for a fit 20 year old). So he would work as hard as he can for 1 minute then go into recovery and stay in recovery until his heart rate slows to 120 beats per minute.
Variable Work, Variable Recovery
This method varies work time AND recovery time based on preset work heart rates and recovery heart rates. For example using the same example of a fit 20 year old you might set a goal work heart rate threshold at 180 beats per minute – meaning that you keep him working hard until his heart rate hits this work threshold and then immediately begin recovery. Then you would keep him at a reduced work rate until he hit a predetermined recovery heart rate threshold such as 120 beats per minute. This is a highly sophisticated and highly individualized way of exercising with precise management of work and rest customized to the individual.
Have some fun and experiment with each of these to prevent plateaus in your workout progress!