S.I.T. – Summer Interval Training!

Posted on May 31, 2010 by

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Courtney Townley

If you have been hanging around the Genesis community for even a short amount of time, you have, undoubtedly, heard the training phrase “high interval training”.   Those of you deep in rotation have been up close and personal with this type of training and those of you in fueling or just embarking in rotation are probably aware that there is a strong possibility that intervals will be a part of your training future.   The intent of this article is to clarify what interval training is and why we do it.
High interval training is a method of cardiovascular training that alternates precisely measured high intensity exercise periods with periods of active rest.   Those of you introduced to interval training through the Genesis program are probably most familiar with the 1 minute of intense exercise followed by 2 minutes of active recovery protocol, but the ways in which interval training can be varied are many.
This type of training has been used for decades among athletes to help condition them for competition, but within the past several years, interval training has found its way into mainstream health and fitness programs because of the benefits that it so clearly provides to cardiovascular conditioning and calorie expenditure.
Certainly, because of the intense nature of interval training, it is not appropriate for the untrained client to perform, which is why a gradual progression from doing no cardio to establishing a cardiac base to performing steady states is introduced in the Genesis process before a participant graduates onto the more grueling interval work.
A lot changes in fitness theory year to year as the chemistry of the body and how it responds to different stressors, including exercise, is far from being completely understood by the scientific community.  One irrefutable fact, however, is that in order to lose fat, the amount of calories expended needs to be greater than the amount of calories consumed.   Roughly, a 3500 calorie deficit needs to be created to lose about one pound of fat.  We also know that the body uses 2 primary fuel sources during workouts, carbohydrates and fats.  When performing low to moderate intensity (under 70% of max heart rate), long duration aerobic type activity (better known as steady states to the Genesis community) carbohydrate is initially used as fuel, and as the workout progresses, fat is metabolized.
During anaerobic activity (without oxygen), short bouts of intense exercise (think interval training and weight training), the body uses primarily stored sugars (carbs) as fuel.  However, studies have shown that this type of exercise burns more total calories because, not only do you burn calories during the workout, but you increase your resting metabolic rate for up to 24 hours post exercise due to excess post-exercise oxygen consumption, which ultimately helps you burn more fat stores in the long run.
Excess post-exercise oxygen consumption, or EPOC, is basically a fancy term for the process by which our bodies utilize calories after an exercise sessions to put us back into a pre-exercise state. Simply put, EPOC is the energy our bodies require to recover from exercise; the more intense the exercise the greater duration of EPOC.  This means your body will continue to burn calories at a higher rate for hours after you leave the gym.  Steady states, on the other hand, done at lower intensities for longer durations of time have been shown to have little or no effect on EPOC.  So while steady states done at moderate intensities do burn a significant amount of calories during the workout, the resting metabolic rate is the same post exercise as it was pre exercise.
Interestingly, heavy resistance training and circuit training have both shown to increase the EPOC effect on the body, as well.  For more information on this, check out the article, Exercise After-Burn: Research Update, by Chantal  A Vella, Ph.D. and Len Kravitz.
Other benefits of interval training include:  increased heart and lung capacity, better physical adaptations to steady states (you use less energy for longer exercise periods), less time spent exercising, reduced boredom, more speed, and more power for fitness and athletic endeavors.
Again, it is worth repeating that interval training is only appropriate for individuals who have been conditioned to do them along a fitness progression and steady states are a vital part of that progression.   In other words, don’t panic if you aren’t doing interval training!  By doing steady states during fueling or even rotation, you are preparing your body to be conditioned for interval work down the road.