Pritchard: Today’s most popular conditioning method; HIIT (column)

Jimmy Pritchard
Better Version of You
Jimmy Pritchard is the director of strength and conditioning for Ski & Snowboard Club Vail and is a certified strength and conditioning specialist through the National Strength and Conditioning Association.

One of today’s most popular conditioning methods is coined high intensity interval training, or HIIT.

Its touted benefits include increased post exercise oxygen consumption, leading to what is in layman’s terms is known as the “afterburn” effect, as well as a shorter overall workout in comparison to a steady state aerobic bout.

It is difficult to refute claims that HIIT does provide some of these benefits, however, many individuals lack the understanding of how to structure such programming and disregard the importance of still including low intensity steady state conditioning into their overall program.

What is HIIT?

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Due to the fact that HIIT serves as an umbrella term for several different training methods, it can be difficult to pin an exact definition. Classically, it has be defined as a brief bout of intense exercise followed by an intermittent rest period for several rounds.

Altering the work-to-rest ratio ultimately determines which energy system is being targeted. The all-too-common 1:1 work to rest ratio of 30 seconds is frequently chosen, leading to circuit training rather than high intensity intervals.

How should you structure HIIT training?

HIIT training should not be viewed as one specific method; what must be contemplated, rather, is the goal of the training session. If the goal of a session is to do sprint intervals, a 1:5 to 1:20 work to rest ratio should be used. This means if you execute an all-out sprint (95-100 percent max intensity) of 8 seconds, the rest period necessary before beginning another set should be a minimum of 40 seconds and err closer to 160 seconds for full restoration of the ATP-PC system.

If insufficient time is allotted between intervals, lactic acid will accumulate and the ability to execute at the highest intensities will ultimately drop. Consequently, this explains the major fallacies with following an often prescribed 1:1 work to rest ratio of 30 seconds, as one will not be able to sprint that long and ultimately end up using the anaerobic lactic system shortly followed by the aerobic system to fuel their work. A firm understanding of how the human bodies energy systems work as well as the time for fuel substrate restoration is when positive adaptation is desired.


One last but often overlooked point in regard to energy system training is how it effects the overall training program. High intensity work can often be demanding on the central nervous system.

If one desires to integrate HIIT work into their program, they should start with the minimum effective dose and only add more when necessary.

Maximum strength work, sprinting, power and max speed workouts all place high demand on the body both physiologically and neurologically. They are excellent modalities to make positive adaptations and more resilient athletes, when proper rest is allotted. High intensity work should be complimented with an appropriate dose of low intensity work to facilitate recovery and prevent burnout. Firmly understanding all these principles will ultimately lead to truly effective high intensity interval training.

Thanks again as always for reading and have a nice week.

Jimmy Pritchard has a Bachelors in Science in exercise science from Colorado Mesa University and is a certified strength and conditioning specialist through the National Strength and Conditioning Association. He is the director of strength and conditioning at Ski & Snowboard Club Vail. Contact him at 970-331-3513 or

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