Saturday, October 17, 2015

The High Intensity Interval Training Revolution

I have been in the fitness industry for decades now, and too often I see the same people doing the same workout in the gym and getting the same results - that is - no improvement in their fitness or body shape.  Wasn't it Albert Einstein who said the definition of insanity was doing the same thing over and over again and expecting different results? Sometimes we just have to mix things up. 
The gym scene is one area in the fitness, health and wellness genre that often sees cycles and fads in 'new' training regimes "guaranteed to bring results" however, the things that actually do work are the "old school" methods that worked but disappeared into obscurity.  Think about for example, the rise of 'Crossfit'.  The exercises seen in a typical crossfit workout are not new - in fact they have been around for decades and pulled from various disciplines, most notably gymnastics - throw them all together and we have this fitness revolution rebranded as "Crossfit".
One thing is for certain - to gain any kind of change in body weight, body shape or fitness, the body needs to undergo a form of physiological stress.  If the body is not stressed enough, no changes will occur after adaption to the stress has occurred - that is, whilst there may be initial changes for a sedentary or untrained person who commences training, the changes will be short term. This does not mean the person will regress - it means that body weight,  shape and fitness are more likely to stay static if the training regime stays the same. One could argue that if that is the aim, then there is no reason to add any changes and I agree, however for the numerous people I know who come to the gym for that very reason - to reduce weight, change their body shape and increase their fitness further; they MUST do something different to elicit those changes. 
High intensity interval training (HIIT) has been around for decades, but because it hurts and because the myth was to burn fat we needed low intensity continuous training, it was largely left to track and field athletes to play with. Numerous studies have been done (Larsen & Jenkins; Essen et al; Billat) which show the benefits of HIIT over continuous low intensity training to improve fat metabolism (or the use of the energy system that promotes fat as the preferred fuel source). Getting into the science behind this is complex, so in lay terms; higher intensity workouts will improve fat burning and fitness. 
Back in 1996 a study was done by Izumi Tabata and his associates, where they used a protocol of 20 seconds high intensity exercise followed by 10 seconds of rest, repeating this cycle 8 times - a total of 4 minutes. The results were astounding, with significant V02 max improvements (the maximal rate at which your body can utilise oxygen - and often the measure by which we define "fitness'), AND significant improvements in anaerobic capacity - that is the ability to work maximally at a high intensity before lactic acid inhibits muscle contraction.  There are numerous physiological reasons why these changes occurred that are beyond the scope of this post, but you can access Tabata's study online and decipher the maths for yourself if you are interested in knowing why these improvements were made. They were incredible results for a 4-minute regime. This study has come to be known as the "Tabata Protocol" and has made a huge entrance into the fitness world recently even though it is 18 years ago that Tabata did his study!
So what might a typical Tabata work-out look like? It depends entirely on what you are training for, but let's just say you wish to offer your body something different to do in order to elicit the changes I wrote about earlier in this post. I recently offered my work colleagues a simple workout using the Tabata protocols that took 25 minutes, as follows:

  • 2 minute gentle jogging warm-up
  • Sprints (20/10/8x)
  • Push-ups (20/10/8x)
  • Jump squats (20/10/8x)
  • Step-ups with dumbbells (20/10/8x)
  • Burpee with star jump (20/10/8x)
  • 2 minute gentle jogging cool-down
Each set had a 30 second recovery before starting a new exercise. Such a workout is easy to do anywhere, requires minimal equipment and is completed in a short time frame. Most people would be hard-pressed to do more than 30 minutes of Tabata training, and in fact Tabata himself argued that 4 minutes a day was all that was required to elicit changes.
As a group fitness instructor, I have seen the rise of Tabata-type training enter the class format, with sections of Les Mills RPM and Body Pump classes utilising it as well as the advent of GRIT classes which capitalises on interval training techniques to gain favourable results. All in all, HIIT protocols are certainly the current trend for fitness improvement and as the studies I have mentioned here show, HIIT has been around for a long time and is likely to remain so due to the favourable results people get when including it in their training programmes.

1. Tabata I, Nishimura K, Kouzaki M, Hirai Y, Ogita F, Miyachi M, Yamamoto K. Effects of moderate-intensity endurance and high-intensity intermittent training on anaerobic capacity and VO2max. Med Sci Sports Exerc. 1996 Oct;28(10):1327-30. PMID: 8897392.
2.  Paul B. Laursen and David G. Jenkins, The Scientific Basis for High-Intensity Interval Training Optimising Training Programmes and Maximising Performance in Highly Trained Endurance Athletes, 2013.

3. Essen B, Hagenfeldt L, Kaijser L. Utilization of blood-borne and intramuscular substrates during continuous and intermittent exercise in man. J Physiol 1977; 265: 489-506 62.

4. Billat V, Renoux JC, Pinoteau J, et al. Times to exhaustion at 90, 100 and 105% of velocity at V . O2max (maximal aerobic speed) and critical speed in elite long-distance runners. Arch Physiol Biochem 1995; 103: 129-35 67


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