Ask the Coach: How often should I be doing HIIT training?

Coach,

I was curious which training styles you recommend? There's a lot of science and research that says HIIT training is awesome. How often should I be doing it? My goals are to increase muscle mass and at the most run a half-marathon. I am seeing some results in the two to three times a week range. I mix longer steady state workouts in one to two times a week for some endurance, then mid-range two to three times a week. So all in all, six days of cardio and strength training to fulfill my goals to compete in tri or duathlon. Any further guidance for ranges, workouts and frequency would be really helpful.

Thank you!

- Sean

Sean,

My answer to which training style I recommend is pretty simple: Do what you love to do, with an eye on your overall goals, while avoiding injury. It sounds like you have a balanced approach to your endurance training.

For those who may not know, HIIT Training stands for High Intensity Interval Training, in which high intensity intervals of 10 to 60 seconds are alternated with moderate or low-intensity intervals. The idea is to work a muscle to the point of fatigue and then back off and recover at least an equal amount of time, before repeating. It can involve various strength-training exercises and/or running. The basic benefits are that you can build fitness quickly, with shorter workouts, while burning a lot of calories.

I am very much in favor of overall fitness for endurance. Many of our runners and triathletes at Fleet Feet Sports attend Coach Hank’s FFXT Sessions, and they rave about the strength they are gaining, which carries over to their primary sport. The question is whether you are doing primarily HIIT strength workouts or HIIT running workouts. Since you mentioned building muscle mass, I am going to guess you are doing strength workouts.

For frequency, two to three times weekly sounds about right for strength HIIT workouts, but if you were doing run HIIT workouts the recommendation is much less: 2 HIIT workouts in 10 days. You can find many workouts online—just make sure you are starting easy and building with your reps.

A few more thoughts…

You have heard the saying, ”money is the root of all evil”? I can’t confirm that, but I do believe that high intensity is the root of all injury. It has to be limited in any training regimen, and you will need longer recoveries after a hard session. So avoid hard running and cycling sessions on subsequent days.

Building muscle mass and running half-marathons are not mutually exclusive, but there is a reason Kenyans aren’t invited to celebrity arm-wrestling tournaments. Strength will not develop long distance endurance, and long runs won’t give you explosiveness. Keep in mind that longer cardio runs also burn calories, so you may want to consult a nutritionist to ensure you are taking in enough calories to actually build muscle.

There is evidence that HIIT training in running, cycling and swimming can all improve your economy and form, but only if you maintain good form throughout the sessions. I would also be wary of carrying over any HIIT mentality to your racing.

Most runners have enough problems with pacing, (I was doing really well for the first mile then…blah, blah, blah), and the fact that you can tolerate high levels of intensity may result in aggressive racing tactics that will prove unsustainable. So if you are serious about your racing you may want to transition from HIIT intervals to longer tempo intervals as the season progresses.

- Coach Brendan