Have They Found the Perfect Interval Formula?

In the fitness world, buzzwords come and go almost monthly. One that seems to have some real staying power, though, is high intensity interval training, or HIIT. Although it’s not really a new idea, HIIT has really gained ground in the past few years with the rise of standardized forms like Crossfit, Tabata and the Little method. Even with these programs, though, a universal formula for an effective HIIT workout has been sorely lacking.

A group of Danish researchers set out in 2012 to define the perfect formula for HIIT and their work produced some intriguing results worth considering.

The 10-20-30 Study

At the beginning of their research, the team, led by Dr. Thomas Gunnarsson experimented with different ratios that are already at use in other HIIT methods.

Starting with 30-second sprinting bouts, which is a common approach, they found that, although this produced powerful results in their subjects, it’s also a very demanding. Eventually, through trial-and-error, the team fell on 10-second intervals.

It’s not really surprising that the 10-second sprints produced benefits but the exact depth of those improvements has caught many experts off-guard.

Over the course of the 7-week study, veteran 5K runners cut a full minute off their time and 1500-meter runners reduced their time by an average of 23-seconds. And these reductions all happened while slicing their weekly mileage by half. As an added selling-point, these highly effective workouts only took about 20 to 30 minutes.

Workout Details

At its core, the 10-20-30 program is modeled after the Fartlek approach by involving short bursts of running with the speed adjusted by how you’re feeling.

A typical workout following this new protocol would look like this:

  1. A 10-minute warmup. The runners in the original study ran just 3/4 of a mile for their warmup, with no regard to time.
  2. Jog for 30 seconds, run for 20 and then sprint for 10. Repeat this same pattern four more times, follow this routine for five straight minutes.
  3. Walk or jog for 2 minutes as an active rest.
  4. Repeat steps 2 and 3. Cycle through these intervals two or three times. Runners in the study eventually worked their way up to four of these sets.

The original study didn’t list any sort of cool-down but a 10-minute walk is generally recommended to wrap-up your workout.

Because this approach allows you to adjust the speed of each interval, whether it be jogging, running or sprinting, and the number of times you repeat the pattern, it’s easily adapted to your fitness level.

Expert Reception

In general, most experts who reviewed the research found no problems with the study methodology or the program that the study produced. A few authorities have questioned the effectiveness of this type of workout for elite-level athletes.

Others have expressed doubts regarding the trustworthiness of the touted benefits since the subjects used were all experienced runners. These detractors feel that those benefits are to be expected by runners who suddenly shift to an easier training method.

Overall, however, both anecdotal and expert reports have supported the use of 10-20-30 intervals.

Have you been able to incorporate 10-20-30 into your workouts? Please share your experience in the comments.

Sources

http://www.acefitness.org/certifiednewsarticle/2944/have-researchers-discovered-the-ideal-hiit-formula

http://www.ncbi.nlm.nih.gov/pubmed/22556401

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