Interval Training (Part 1)

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Interval Training was the buzz word for the last few years.

I’m happy to say that the buzz and foreign association people used to have with it is gone, and it’s become a staple in the fitness world.


Because it works!

Want to learn all the stuff you won’t find on Wikipedia?…

Before I begin, some people will refer to interval training now as as ‘High Intensity Interval Training‘ or HIIT, so if you see me use that acronym, you know what it means.

Part 2 and 3 will be a brief overview of all the ‘types of interval training’ you are bound to find on Google and a slew of protocols you can actually try.

What is Interval Training?

[toc]Simply put, interval training or HIIT is a type of training where you do a period of higher intensity work — generally a higher intensity than you could tolerate for more than a few minutes at a time, but not exclusively if you consider aerobic intervals — and pair it with a period of rest or lower intensity work.

The amount of work to rest can and will vary depending on the desired training outcome, and the measurement of the work to rest can change too.

For example the Work:Rest can be even, like 30 seconds on: 30 seconds off, or it could be staggered for different training outcomes like 15 seconds on: 45 seconds off, or it could be a distance; 100m on: 300 m off.

You’ll also see me use 3:1 or 1:6 in describing different protocols below, which always means work to rest ratio (work:rest), but you’ll always see me record the unit of measure.

For a quick look of a few different interval protocols used to train the three major energy systems, please see this article.

Why Interval Train?

Recently at a fitness conference, I witnessed a noteworthy and reliable cardiac rehabilitation specialist give a presentation on the interval training they were using in their cardiac clinic to help people recovery from conditions like heart attacks, peripheral artery disease, angina, stroke, etc…

Now if you know anything about cardiac rehab, you know this is generally considered a faux pas.

By far the most common exercise recommendation for cardiac rehab patients is monitored long slow aerobic training.

Unfortunately this the norm and there is, in general, a strong fear about eliciting higher intensity training on an already stressed cardiovascular system, even though I’ve never personally read any unequivocal proof that higher intensity interval training causes these cardiovascular problems, or that they should be considered dangerous in anyway.

It remains a popular assumption, even in the medical community, that high intensity is bad.

I disagree.

From a practical stand-point, if you’ve ever seen or worked with someone recovering from a cardiac issue, it looks exactly like interval training already because they can only tolerate a certain amount of work for so long anyway before they simply must rest.

What do most fitness professionals already recommend for people who want to start running?

Walk-Run protocols.

What are walk-run protocols?

Interval protocols…

…Getting back to this particular researcher and cardiac car specialist, he confirmed my thoughts.

He asserted that the fear of using interval training in cardiac rehab settings isn’t supported in any of the research he’s seen either, actually I think he summed it up best:

For most of these people, all they can do is a form of interval training anyway.

From a practical point of view, most of our lives are already spent in a constant state of interval training, and it makes a great deal more sense that when trying to get fit, interval training is probably the way to go.

If for no other reason that to keep the quality of your work output high, and allowing rest when you need it.

It is far easier for instance to learn how to run well, using an interval protocol, because it permits rest.

Rest keeps a higher quality output going for longer, making interval training overall, probably safer, less taxing and more effective.

Remember Work + Rest = Success

A History and the Science

Interval training’s rise to popularity got it’s start with a Lavel Study published in 1994.

The often misquoted study, was heralded as ‘yielding 9x‘ the amount of fat loss when compared to steady state cardiovascular exercise or ‘long-slow-distance’ cardiovascular exercise that required twice as much work.

This is not entirely true, the results actually revealed 3x the results with half as much work.

The reason it got inflated had more to do with a fudged mathematical formula applied to the difference in duration of exercise and the changes in body composition as measured by anthropometry.

The study is often criticized because less than a kg of total weight loss was present after 15 weeks of training, however, you couldn’t deny that it still worked better than steady state work, and it sparked enough interest to open the flood gates of research.

One might also assume given other research that fat loss would be dependent on the starting point, and no doubt would have been accelerated by nutritional intervention in combination with exercise intervention.

Since then the famous Tabata Study, published in 1996, and it’s follow-up, published in 1997, showed us that we could significantly improve anaerobic and aerobic fitness, with a mere 4 minutes of training per session.

Whereas the long slow steady state cardio comparison, only improved aerobic fitness and not by much over this much faster protocol.

Now contrary to what many people believe, this study — and actually most studies done in regards to interval training — was only applied to markers of energy system development, and not weight loss or fat loss.

More recently, the work of Dr. Steven Boutcher, in Australia, did start to look at fat loss.

His research has given an implication that 8 seconds on, 12 seconds off, might be the best protocol for fat loss, if only compared to the 3 other protocols he used, over the short-amount of time he experimented with them, so more research is obviously needed.

I would argue that there could never be a ‘best’ protocol, in that the body eventually adapts to whatever you throw at it, and you would have to mix the protocol up eventually to continue to make progress.

As I’ve indicated before in my work, this seems to occur generally anywhere between 3-6 weeks depending on ability or experience.

Even in regards to the initial Lavel study, I would be willing to bet had they not done the same thing for 15 weeks, there would have been better results across the board, though difficult to actually research a singular variable in this way.

However, that being said, it seems that interval training can lead to positive hormonal changes, fat oxidation (post-workout) and improvements in both aerobic and anaerobic fitness.

It also seems to preserve muscle mass and manipulate metabolism in a positive light, which means better results in less time overall.

The problem with research is the need to isolate variables, though isolation of variables (like trying to isolate a muscle) is nearly impossible to do, research can still at least shed some light on what I think we should already know.

The leanest athletes on the planet are involved in intermittent power sports, not long-slow endurance sports.

Sprinters for example very rarely work hard for more than 25 seconds (200 m or less roughly) and they look like this:

On the left is a marathoner.

Anyways, visually I know who I prefer to mimic, with my training.

Getting Started

What you are about to read in Part 2, is a huge overview of a lot of different types of intervals, there are more than you know, believe me, it took me a while to write this, just because I kept thinking of other ways I’ve utilized interval training protocols over the years.

Just when I thought I was finished…

…There was more.

But before you begin, what criteria do I have for Interval training?

If you’ve never done it before, or have and possibly ended up injured — injury with interval training is typically a result of too much too soon, a mobility issue, a strength issue, or generally a lack of ideal homeostasis, all of which can typically be addressed with other sound training principles — doing it, then you probably want to ease into it gradually.

Many people ask about the safety of Interval Training.

Isn’t it more strenuous on the body?

Shouldn’t you have a strong aerobic base first?

As it turned out above, probably not…

Though I generally don’t recommend doing more than 30 minutes worth of it at any given time, and very rarely more than three times per week. 

That being said I played basketball and volleyball for years (both Interval-esque sports), and many of our practices, training sessions and games, would be 1-3 hours long of a start-stop form of practice for 4-6 days a week.

With good nutrition, a lot of sleep, appropriate progression leading into it (starting small and working up to greater volume) and an appropriate amount of variance in intensity, you could probably do more, but I just rarely see the need from a typically ‘gym’ viewpoint.

Often the point, as you’ll see, of interval training is to spend less time in the gym, not more, while getting better results.

I used to recommend that everybody work up to at least 20 minutes worth of long slow aerobic work at a rate of perceived exertion of about 6 or 7 out of 10 — 10 being the hardest you feel you could possibly work.

Ironically enough though, this usually meant starting with running for 1 minute, and walking for one minute, then adding a minute to the run every time you felt capable until you could run for 20 minutes, which if you haven’t already guessed it by now, is an Interval Protocol!

Basically I was always recommending intervals to build an aerobic base anyway, but if you want to be extra cautious then you could continue to follow that principle, but I’ve since switched my point of view.

What do I recommend now?

Depends on the type of exercise typically, but a good time-based starting protocol is 10 seconds on, 50 seconds off (typically a 10 second sprint, followed by 50 seconds of walking) or 15 seconds on, 45 seconds off.

Now there may be technical issues in someone’s ability to run, but I actually find it easier to teach people how to sprint, than to run at sub-maximal speeds, so interval training like this allows a lot of time for coaching while you catch your breath.

Rest permits again, high quality work output consistently, which helps ingrain better movement patterns, which leads to more effectiveness for not only technique but also in building a conditioning base.

Try it for 5 minutes even, then gradually work up to 20  total.

Continue to (weekly or monthly) increase the amount of work, and decrease the amount of rest, until you can work at a 1:1 ratio, and then switch the protocol up entirely, consider a distance based protocol, fartlek, or something else you see in the follow-up articles.

So 3-6 weeks from now, go to a 15 seconds on; 45 seconds off protocol.

Then 20 seconds on, 40 seconds off, then 25 seconds on, 35 seconds off, until you get to 30 seconds on, 30 seconds off.

Remember to should switch things up roughly every month, so this means you have to change the type of interval protocol you’re working on as I note above, or the energy system you’re trying to develop, and in many cases a hybrid of both of those changes.

Look out for Part 2, which is a juggernaut of a resource…

See this article again for more info on energy system development.

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