Forging fitness through words

Concepts 101: Fitness Science (Part 2/2)

This article is a continuation of PhysicalBLUE 101 and is an expansion on the #2 Concepts. This is part 2/2.

These concepts of fitness science could easily have research papers written about them and their applications (and there are!). Though it may seem long, this is actually a highly condensed list of highly advanced concepts. Most of these will have longer individual articles dedicated to them in due time – once I release them, I will be sure to link them to each of the titles below.

Fitness Science Concepts 101 List

Part 1

  • Non-Exercise Activity Thermogenesis (NEAT): Calories burned while doing activity unrelated to exercise can have a profound effect on fat loss and muscle engagement.
  • Continuous Muscle Engagement: The importance of consistently activating muscles, even on rest days.
  • Aerobic vs. Anaerobic: The difference, and the foreshadowing, of oxygen’s huge role in exercise.
  • Isotonic vs. Isometric: The difference, and how it can affect the type of muscle you may or may not want – lean and long versus bulk and short.
  • Compound Movements: Multiple muscle engagement, why they are important and how they can help.

Part 2

  • High Intensity Interval Training (HIIT): How combination aerobic and anaerobic exercises in rapid succession can completely rewrite the book on fat-loss.
  • Afterburn training: Marketing lingo for new workout routines that are monopolizing on HIIT in creative ways. Here I will explain the concept of afterburn, massive calorie burn after exercise.
  • Plateauing and Muscle Confusion: The concept of your body acclimating to exercises and receiving decreasing marginal returns. How to combat the plateau effect through exercise variety, the main concept behind P90X.
  • Exercise Dividing: Splitting workouts to two separate times of the day. How you confuse your body into burning reserves on the first round and tap into fat stores to finish the second.
  • Stretching & Warm Ups: Extremely important and oft overlooked steps.
  • Sleep: How much you need and it’s role in muscle repair.

This article covers Part 2

High Intensity Interval Training (HIIT)

This is a money maker concept. Literally, there are dozens of pay-for programs out there that utilize the concept of high-intensity workouts to create a weight loss exercise regimen. Lets dive in to see what they know.

What is HIIT?

High Intensity Interval Training (HIIT), sometimes referred to as High Intensity Intermittent Exercise or HIIE, is training that alternatives back forth from aerobic to anaerobic exercise.

It is perhaps most commonly seen in distance athletes like runners or cyclers. An example would be 8 minutes of slow to medium pace then 2 minutes of fast pace then repeat several times. Interval periods vary, intensities vary, nothing is cut in stone except the fact that it goes back and forth between the two.

What is all the rage?

Well, after years of research (and even more currently on-going), it has been shown that there are huge athletic benefits of interval training. Not only is it a great fat burning tool, but it has the ability to improve speed times and distances based on its affects towards what is called the VO2 max, an indicator of the maximum volume of oxygen our body can transport to our cells. If you are or want to be a long-distance runner, this is something you should absolutely look into and an individual article will be written into VO2 max as well.

However, lately the concept of HIIT has been translated into non-distance workouts. These are workouts that mimic the concept of HIIT but without the running and the cycling and compacts it into a more manageable level, especially for those of us who despise cardio workouts. These are where workouts like InSaNiTy come from, and oh my god, these things are no joke! They will push you to the absolute limit, but I will go more into that in the next section, Afterburn Training.

Afterburn Training

Afterburn training is actually the same exact thing as HIIT, it simply focuses on marketing an effect that occurs after completing interval training. And that is the fact that HIIT workouts are responsible for burning a large amount of calories long after the workout is actually finished.

The same effect occurs after any type of exercise actually, but no known workouts have a more dramatic effect than HIIT training. As with any other workout, your body will expend a certain amount of calories towards muscle repair. It will break down lipids and use energy to heal micro tears and tissue damage that occurs during exercise. After HIIT, when individuals complete a rigorous set of aerobic and anaerobic rotations, the body seemingly goes into frenzy to repair muscles and burns a significant amount of calories for what can be a very long time, 36 hours in some cases.

Why does this ‘afterburn’ happen?

Well, there is a lot of misconstrued information out there about this, but the real answer to this question is still under a lot of research. It is an interesting dynamic that people have learned how to make gains from doing exercises but the science hasn’t quite figured out why it is so successful.

Here is what we do know

Make sure you have read the aerobic v. anaerobic section above or else this might be difficult to understand.

Disclaimer: most of this is supported by research but there a few of my own concepts that I introduce myself in order to ‘stitch’ together the picture/fill in the gaps.

When you push your body into anaerobic conditions, your body is operating without oxygen, so you create an oxygen deficit. But by shifting back to an aerobic exercise immediately after the anaerobic burst, some, if not all, of that oxygen deficit is maintained, since the oxygen that you are breathing is going directly to the aerobic exercise.

Put this in the eyes of evolutionary biology. Our ability to run helped us either pursue our prey during a hunt or flee from a predator in a bad situation. When our body allowed, it provided us energy based on our oxygen availability from every time that we inhaled a breath of air. But it also developed an emergency energy source for extreme situations where we need to exert ourself, I am referring to anaerobic exercises. Lets say you are a particularly confused hunter and you accidentally throw your spear at a black bear that you mistook for Bambi. Realizing your mistake when the bear growls and charges at you, you take off in a hurry. Your body is suddenly receiving all these commands saying, ‘move these muscles god dammit‘, so it does so, but it will quickly realizing that you are not pacing yourself at all, you must be in danger. What it does at this point, by converting to anaerobic exercise, is making an investment, on margin. For those of you that skipped finance, an ‘investment on margin’ refers to making an investment with money that you don’t have. Your body is reasoning that, ‘hey, I don’t have enough oxygen to do what I want right now, but I will use my reserves to produce energy for the time being and pay off my oxygen debt later‘. Now lets say that you safely escape the situation, you immediately slouch against a tree and breathe heavily. That is your body absorbing as much oxygen as it can to restore your immediate reserves. Once that initial panting stage ends and you regain your breathe your body is actually still paying off its oxygen debt. But it because it is so innately talented at math and finances, it has created a long-term payment plan. In plain English: the human body, instead of huffing and puffing, is now siphoning some of the oxygen from your rested breathing towards your muscle repair.

Now, back to HIIT, all of the same principles apply except that you never slouched against a tree to regain your breath. In fact, your body went back to an aerobic balance which demanded all the incoming oxygen meaning that your oxygen debt or deficit still needs to be paid off. But then, to your body, something crazy happens – you starting sprinting… again. Did this idiot piss off another bear? Whatever the case, your body makes its best effort, as it always will, to give you what you need, which is why we are capable of completing HIIT. Yet something happened to get there, namely, your body is now in trouble with the oxygen mafia loan sharks because it is not paying up on its dues.

Once you complete a HITT session, you have racked up a large disproportion of oxygen and your body has to struggle hard to repair those muscle glycogen reserves and repair those muscles. This is where a large bulk of the burned calories come from in Afterburn training. However, there are some extreme cases where up to 90+% of the calories burned in an exercise occur afterwards and it just doesn’t seem like it all can come from an oxygen deficit – maybe it does, maybe it doesn’t, when research does catch up though you can be sure I will be here to report it!

Whatever the case, the truth is that it does work. We have strapped up participants and studied exothermic reactions as they perform HIIT and the evidence is all there, we just simply aren’t sure why yet. But the way I see it is, someone left $50,000 in cash at my doorstep for me, I will try to find out why someone gave it to me, but I’m also going to use it!

If it is still unclear to you, picture this…

Here is a graph demonstrating the basic concept.

For simplicity: VO2 (volume of oxygen transported to body) is treated as a constant 30 liters per minute here, when in reality it will fluctuate. The same is true for oxygen demand which is also going to fluctuate based on your specific movements.

Example Oxygen Deficit Graph from High Intensity Interval Training (HIIT)

As you can see, through the process of switching in and out of anaerobic exercises but always maintaining an aerobic interval in between, your body accumulates a deficit of oxygen that it has to ‘correct’ in the hours after the workout.

Summary and how to proceed

So now that you have a better understanding of how HIIT can cause calorie ‘afterburn’, you can start to see how this type of training can really blast your fat stores. By burning up calories from one workout even while you are sleeping or going about your day. This is why monetized programs have sprouted up left and right trying to make a buck on understanding this concept. They give you thought-out workout plans to execute in one neat plan in order to shed fat. A big up and coming one is the InSaNiTy workouts by trainer ‘Shaun T’ which adds a huge bit of flair in their creative workouts (they are indeed insanely difficult to do), but they still operate under the basic premise of HIIT.

You are can get creative on your own and make your own HIIT regimen, or, in the next few months once I am able to produce more articles for PhysicalBLUE, I will be releasing an HIIT program of my own. Keep in tune by following PhysicalBLUE either through facebook, twitter, RSS, or the e-mail newsletter.

Plateauing and Muscle Confusion

Plateauing or plateaus refers to the concept where our body becomes prepared for workouts we do regularly and gains from doing them begin to level off. It refers to a situation where if you woke up and did 100 pushups every single morning for a year, your body will hit a plateau where it can easily perform the 100 pushups and you will cease to make any gains.

Now, there is no exact algorithm that allows us to determine how long it takes for our body to achieve a plateau because it is attributable to an individual’s unique physical design. It also depends on frequency of your exercises and how diverse they are. The generally accepted rule of thumb is about 2-3 months.

In order to continue losing fat or building muscle or whatever gains you may be after (endurance, performance), you need to avoid these unassuming plateaus. This slightly blends into what I explained above with isometric movements and fiber recruitment; your body learns how to perform a specific movement using its ever-readjusting economy of energy. When your body goes at a mystery workout, it has to overcompensate for the ‘what if’ factor, it is not sure what it will need to complete the exercise. Subsequently, it turns out that it was correct and that the new workout challenged your muscles in ways it was unprepared for, which results in muscle repair, muscle strengthening, and/or other improvements based on whatever exercise you are performing. After repeating this routine however, your body gets better and better and preparing itself for the workout until it is 100%, at which point, gains become sluggish.

Think of it this way

You are having a big house warming party at your new place and 20 of your friends are coming over for food and drinks. As the host, you need to get to the grocery store and buy everything you need. The problem is, you have never prepared food for this many people and on top of that, some of them are big eaters and some of them are picky eaters, how in the world are you going to make sure that you are able to host everyone? You end up buying a bunch of everything just to cover your bases, you go home and you cook up a bunch of recipes reasoning that the more types of food you prepare, the higher chance the people will be satisfied. Now the hour has arrived and people are trickling in to your house, everyone is excited about the food but then the wrench in the gears, your friend’s wife is vegan! Even though they insist against it, you are determined to satisfy your guests so you make a quick run to the store to get appropriate food for her. Everyone ends up having such a great time that you invite them over for another party next week. This time however, are you going to forget to prepare for a vegan? No.

Do you see how this applies to muscle plateaus? Your body is over-preparing when you are performing workouts you have never done, but as it does them and is able to repair itself, it becomes better prepared for the next time around. The only difference is that this isn’t as simple as a house warming party, this is about maintaining countless cellular reactions in your muscles to charge your movement. Still, over time, your body continues to forge itself and becomes accustomed to that specific exercise.

The worst thing you can do

And it happens to so many people, is to not understand this concept. How many people do you know that spend so much time in the gym but yet they never really look all that different? Maybe you are one of them! Tough I can’t be certain without specific details, it is very possible that you or they have been nursing an exercise plateau since day one. Some people do nothing else except use an elliptical machine, thinking that it is as simple as calories eaten – calories burned = gain. It isn’t. To make real gains you need to mix up your workouts and be doing exercise movements that your body has not acclimated to. If you aren’t, you are opening door to decreasing marginal returns.

What is Muscle Confusion?

Plateauing and Muscle Confusion are the main concepts behind Tony Horton’s P90X program by Beachbody, LLC. Muscle Confusion is the process of eliminating muscle plateaus diversifying workouts. Doing the P90X program will put you through everything from basic lifting, cardio, stretch workouts, plyometrics, yoga, martial arts/boxing, it is really some other worldly stuff.

So here is the overall theme, if you are trying to make gains, repeating the same workout is not enough. You need to switch it up for your body in order to make breakthroughs in fitness because that is the only way that you are going to fire up your metabolism and force muscle repair – you have to be giving your body exercise that it is less equipped to handle, that is how you get it burn energy via fat in attempt to strengthen your weaker forms.

Cardio Dividing

This is another item that is difficult to find information on, Cardio Dividing is a term that I coined for doing two cardio workouts in one day. It is different from two-a-days, which I will go over in a separate article, in that it is only for cardio and it requires a few unique aspects of the workout.

When you do a long session of cardio, runing, biking, or swimming, you are exhausting your sugar reserves and fatigue your muscles. This is normal. So say you did 45 minutes of cardio at 1pm, showered and cleaned up, but then did another 45 minutes at 8pm, what happens? Well, your immediate energy reserves have not replenished yet and your muscles are still somewhat fatigued, so when you do your second workout your body has to dig deeper to fuel you. Quick search on Google and you’ll find that there are dozens of studies that have shown that breaking up workouts yield more calories burned and higher fat loss over a period of time, but not many of them explain why.

So then, why?

Well it comes down to what I began to mention above, your muscles are out of energy reserves. When it has no immediate energy, where does it go? To your stored energy, aka fat deposits. A research study I read years ago in university measured the results of two groups of participants, the control group performed a 60 minutes session of cardio and the experimental group performed two 30 minute sessions of cardio with an hour rest in between. They found that with the experimental group, not only was the total amount of calories burned higher, but that in the second session, somewhere around 70% of energy came from stored lipids. They theorized that the process of heating up the body to exercise took a large amount of calories and that doing it twice was where the bulk of additional calories came from. I disagree completely that it was responsible for the ‘bulk’ of additional calories and believe it has more to do with the calories involved different types of energy burning (stored fats vs. available energy from digestion). The interesting aspect of that case was the spike in fat burning – that is, after all, what we are looking for!

What I propose is this:

If you have the time to do so, try to Cardio Divide, split up your sessions into two a day with rest period in between. Furthermore, I want you to apply the concepts that we learned above with HIIT, you need to maximize the absence of reserves in the second workout by pushing yourself in the first one. By depleting your local glycogen stores and perhaps some of your high energy phosphates, you will be setting yourself up for an emergency situation in the second workout where your body has to ramp up the energy harvest from your body fat.

Stretching & Warm Ups

Stretching and warm ups are a very important part of any routine I recommend to someone, it is all about increasing oxygen flow and taking care of your muscles, tendons, joints, and ligaments.

I have written a separate article, Warm Up 101, that goes over this process in much more detail. It is very important that you be taking advantage of these exercises because they can make a huge difference, prepping your body and elevating your heart rate before beginning a workout help adds explosiveness to your movements and ramp up oxygen delivery by way of elevated VO2 max.

As for stretching, if you have want to decrease soreness, build fuller and more rounded muscles, elongate your muscles, and/or just take better care of your body I highly recommend it.


Please don’t make me explain this… by now, after reading all of the above, you know that your body is a complex machine and an ultimate process of staying in shape is to be able to recharge your body, engage in muscle repair, and reduce fatigue. That means sleep. The correct amount to get is not too little, and not too much:

Goal: Give your body what it needs by sleeping 7.5 – 8 hours a day.

Last words

Concepts 101 is a very dense section of information. It is okay if you haven’t completed understood everything I have explained here because technically, understanding just one of these concepts, however small, is enough to help you. As you keep up with PhysicalBLUE, articles will be released that go into extra detail and elaborate on each of the concepts above. If there is any specific concept you would like me to cover first, please send me an e-mail because your comments absolutely will affect what I write up next!


You completed the PhysicalBLUE Concepts 101 section

If you haven’t read it yet, you should move on to Nutrition 101: Part 1.

1 Comment

  1. Cornelia Shike Cornelia Shike
    17 May, 2012    

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