As I explained in Part I of this series of articles on exercise intensity, Exercise Intensity: the #1 Key to Building Muscle, Part I; Exercise Intensity Defined, exercise intensity is simply “the amount of contraction that you generate in the working muscle, per unit of time“.
So when it comes to strength-training, weight-training and bodybuilding, the more contraction that you generate in the working muscle per second, the harder the muscle is working, and the higher the intensity is; and thus the greater the muscle growth stimulation. And the greater the muscle growth stimulation is, the more muscle you’re likely to build.
So for maximum muscle growth, you need to generate “maximum contraction per second”, which is maximum intensity, for any strength-training or weight-lifting exercise that you do.
And as I explained in Parts I and II of this series, there are two types of contraction relevant to strength-training and building muscle: resistance-induced contraction (RC), and dynamic contraction (DC). So you have to maximize both types of contraction simultaneously throughout the entire exercise, in order to generate maximum intensity in the working muscle, and thus build “maximum muscle in minimum time”.
And overall in Parts I-IV of this series, I covered the “5 factors” that determine exercise intensity. And each one of those 5 variables can significantly affect the intensity of any strength-training or weight-training exercise that you do, and thus the anabolic result that you obtain from that exercise. So I provide a summary of them below:
The “Big 5” Factors That Determine Exercise Intensity and Muscle Growth
1) the amount of weight that the muscle is actually working against
2) the amount of leverage that the muscle is working against, if any
3) the rep tempo ( or rep cadence), which is the “speed of execution” of the reps; if reps are done, as opposed to static holds
4) the amount of dynamic contraction generated in the muscle
5) the amount of time it takes, to do all of the above
Note that #1-4 pertain to the “amount of contraction” that you generate in the working muscle. Specifically, #1-3 refer to the “amount of resistance” that the muscle is working against; and thus the amount of resistance-induced contraction (RC) generated in the muscle.
And #4 refers to the “amount of dynamic contraction” generated in the muscle. And last but certainly not least, #5 pertains to “how much time” it takes to generate all that muscular contraction from #1-4.
So by now, you should know that there’s a lot more to exercise intensity and building muscle than just the “amount of weight” that you lift. And since all 5 of those variables are required for any correct, complete definition for exercise intensity, as it relates to weight-training and muscle growth stimulation, you should use them as criteria to evaluate any definition for exercise intensity that you find; if your plan is to use that definition to build muscle. Especially if your goal is to build “maximum muscle in minimum time”.
An Analysis of Some Commonly Accepted Definitions for Exercise Intensity, As it Relates to Weight-Training and Muscle Growth Stimulation
In Part I of this series, we analyzed the definition for intensity handed down to us by Mike Mentzer, one of the bodybuilding greats of the 20th century. And as I explained, Mentzer’s definition, although incomplete and insufficient for practical application, is potentially one of the best definitions for intensity that’s been given to us.
So now let’s analyze some of the other most frequently accepted definitions for intensity, using “the Big 5” as criteria, and see how they size up:
1) “Intensity is the percentage of your ‘1 rep max’ ( 1 RM), that you use to perform a weight-training exercise”.
Some of you may know this definition as the correct and ideal definition for intensity, as agreed upon for years by experts in the fields of strength-training, weight-training, bodybuilding and exercise physiology.
Well, good luck using a definition like that to achieve maximum intensity, and build “maximum muscle in minimum time”. I can assure you that it’s just not going to happen; regardless of what the “experts” say. And that’s because this definition has serious shortcomings.
First, your “1 rep max” means the “maximum amount of weight that you can possibly lift, only 1 time”. So this definition is simply saying that the heavier the weight is that you lift when doing an exercise, the higher the intensity of the exercise; and thus the greater the muscle growth is likely to be.
But as you can see, this definition for intensity is very incomplete. It includes only one of the “5 factors” that determine intensity: the “amount of weight” used for the exercise. And as I’ve emphasized in this series of articles, and as you can see from reading the list of the “big 5” above, there’s a lot more to intensity than just the “amount of weight” that you lift, or use for the exercise.
Now, you can use this definition for intensity successfully if “powerlifting” is your thing. And that’s because powerlifters aren’t concerned with how much intensity they generate in a muscle, or how much muscle they build; at least not when they’re powerlifting.
The sole purpose of powerlifting is simply to “lift the heaviest weight that you possibly can”, any way that you can. So basically, when you’re powerlifting, the “amount of weight” that you lift is the only factor that really matters. And that’s why powerlifters are often not as muscular as bodybuilders; regardless of how much weight they can get up.
But if muscular hypertrophy is your goal, following this definition for intensity will limit your severely. In which case, you’ll probably never build or develop the body you want. And that’s because when it comes to building muscle, all 5 of those factors I listed above can play an important role.
And even the one factor that this definition for intensity does include (the weight factor) isn’t addressed adequately. And that’s because the definition fails to specify that when it come to the weight factor, it’s “how much of the weight that the muscle is actually working against” that ultimately determines how much resistance-induced contraction (RC) is generated in the muscle; and thus the level of intensity achieved. And that’s not necessarily the same as the amount of weight lifted or being used for the exercise.
As I stated in Part IV of this series, whenever you do reps, the amount of weight that the muscle is actually working against fluctuates, sometimes dropping down to zero, at certain points in your range of motion. So at those points, you would have zero resistance, and thus zero resistance-induced contraction (RC); regardless of how much weight you lift or use.
And that causes the resistance, and thus the amount of resistance-induced contraction (RC) to fluctuate; which then causes the intensity to fluctuate.
Yet amazingly, this definition for intensity doesn’t even take resistance into account. And that’s a big shortcoming. Because ultimately, it’s the “amount of resistance” that the muscle is working against, not just the “amount of weight” being used, that determines how much resistance-induced contraction (RC) is generated in the muscle.
It’s very important to remember that “resistance” and “weight” are not the same. And the “amount of weight“, as important as it is, is only one of “3 different factors” that can determine the total amount of resistance that the muscle has to work against.
In fact, that explains why it’s possible for you to achieve a higher level of intensity and build more muscle, by using a lighter weight, than you would by using a heavier weight; depending upon “how the weight is used“.
And “how the weight is used” is determined by what happens with the other 4 factors that determine intensity: leverage, rep tempo ( a.k.a. “rep cadence”), dynamic contraction (DC) and time.
The bench press is a good example of this fact. The bench press does enable you to lift more weight than does any other chest exercise. But it does not enable you to achieve maximum intensity, or even high intensity, in your pectoral muscles; regardless of how much weight you lift. And that’s because of the changes that occur in those 4 other variables that determine intensity.
For example, the amount of leverage that the chest muscles have to work against is a lot less for the bench press than for other chest exercises, like say, the dumbbell flye. So that lowers the resistance significantly when doing the bench press, for any amount of weight that you use. And that, in turn, lowers the amount of resistance-induced contraction (RC) generated in the chest muscles, and thus the level of intensity achieved.
Plus, you can only generate a relatively small amount of dynamic contraction (DC) in the pectoral muscles when doing the bench press, due to the limited range of motion. You can’t even get close to your points of maximum dynamic contraction (DC) when doing the bench press, as you can when doing a chest exercise like the pec dec. Which means that you can’t even come close to achieving maximum intensity, or even high intensity in the pecs, when doing the bench press; regardless of how much weight you use. For more on that, read my article The Overrated Bench Press; Dethroning the King of Chest Exercises.
But obviously, the “experts” who came up with and decided upon this definition for exercise intensity didn’t know about those other 4 factors that determine intensity.
And yet another problem with this definition for intensity is that it implies that you have to lift weights or do reps, in order to generate intensity. So does that mean you can’t generate intensity when doing isometrics or “static holds”, simply because you’re not “lifting weights” or “doing reps” for those types of exercise? No, of course you can!
The fact is, any time you have contraction in a muscle, you have some level of intensity. Lifting weights and doing reps is not required to generate intensity in a muscle. And the correct definition for intensity would be one that is universal in application, in that it’s relevant to all types of strength-training and weight-training; whether you do full-range reps, partial reps, static holds, isometrics, or simply flexing your muscles.
Yet amazingly, this inferior definition for exercise intensity, in spite of all it’s shortcomings, has been accepted by the experts for many years; and it still is!
So now that I’ve proven the experts wrong in this regard, there’s an important lesson to be learned here: experts are not always right about everything; even in their own area of expertise. We know this to be true without a doubt, because the experts in any field don’t always agree with one another. So obviously, some of them have to be wrong! And they have a right to be wrong. Because even though they are “experts”, they’re also human beings; just like you and me.
2) “Intensity is the ‘amount of weight’ that you lift per unit of time, as you perform any weight-training exercise”.
This definition for intensity is actually better than the previous one, in that it includes one more of the 5 factors that determine intensity; which is time. And any good, complete definition for intensity must include the “time factor”.
Aside from that improvement, however, this definition has many of the same shortcomings as the previous definition. For example, it doesn’t include leverage, rep tempo or dynamic contraction.
So this definition too is incomplete, and insufficient for achieving the goal of generating maximum intensity, and thus maximum muscle growth.
And there’s more: taken literally, this definition implies that you should go through the eccentric phase of motion as quickly as possible, in order to maximize intensity. But actually the opposite is true. The only way to maximize the intensity during the eccentric phase is to “slow the weight down”, as much as you can.
And the more slowly you cause the weight to move during the eccentric phase, the harder the muscle has to work, to resist the pull of gravity. And the harder the muscle has to work, the more contraction is generated in the muscle, per unit of time. And thus, the higher the intensity is. But this definition for intensity fails to account for this fact.
This definition for intensity could be greatly improved, by substituting the word “resistance” for the word “weight”. Then we would get this:
“Intensity is the amount of resistance that the muscle has to work against, per unit of time, as you perform any strength-training or weight-training exercise”.
This modified definition includes 4 out of the 5 factors that determine intensity, since resistance is determined by weight, leverage and rep tempo. So it’s much better than the original definition.
But it’s still incomplete, because it leaves out dynamic contraction, which plays a significant role in determining how much intensity you generate, and how much muscle you build.
3) “Intensity is the amount of energy expended when performing an exercise”.
In regards to practical application, this definition for intensity is somewhat of a joke. How can you measure or quantize the “amount of energy” that you expend when performing an exercise? Obviously you can’t.
So when using this definition for exercise intensity, you have no way of knowing what your current level of intensity is, for any exercise. Thus, you have no way to track your progress with this definition. You have no way of knowing if your “level of intensity” for any exercise was higher or lower, than the last time you did that exercise. And you have no way of knowing if you’re achieving maximum intensity or not; or even high intensity.
This definition for intensity can be improved by defining exercise intensity as “the amount of energy that you expend per unit of time, when performing an exercise”. That would be a significant improvement, because at least it would include the “time factor”, which is essential for any complete definition for exercise intensity.
Nonetheless, “energy” still can’t be measured or quantized when you’re working out. So in it’s current or modified form, this definition is so useless, that it hardly warrants further discussion.
Amazingly, I found it on the website of the venerable Wikipedia. And if you do a search with the words “exercise intensity”, you’ll always find this inferior definition for exercise intensity right near the top of the first page of the search results!
4) “Intensity is the ‘degree of effort’ exerted, when performing an exercise”.
This definition suffers from the same shortcomings as the previous definition. How can you measure or quantize “effort”, when you’re performing an exercise? Obviously, you can’t.
So you would have no way of knowing exactly what your current “degree of effort” is for any exercise, when using this definition for intensity. Which means that you would have no way of knowing exactly what your current level of intensity is, for any particular exercise. And that means when trying to use this definition, you can’t apply the Rule of Progressive Intensity effectively, to achieve prolonged, sustained, maximum muscle growth.
Furthermore, what exactly is meant by the word effort? Well, as I explained in my analysis of Mike Mentzer’s definition for intensity, “effort” can mean 3 different things.
Effort can mean:
1) an attempt to perform a task
2) the energy expended to perform a task
3) the immediate result of the attempt made, or the energy expended to perform a task
So which of those 3 is this definition for exercise intensity referring to, when it says “degree of effort”? It doesn’t specify that. And even if it did, none of those 3 can be measured or quantized anyway.
Furthermore, what exactly is meant by “degree of effort”? Does it mean the “amount of effort” made? Or better, does it mean the “amount of effort” made per unit of time? This definition for exercise intensity doesn’t specify any of that either.
And when we evaluate this definition for exercise intensity by sizing it up against the “big 5”, we find out how useless it really is, when it comes to practical application. It says nothing at all about muscular contraction (which is covered in #1-4 of the 5 factors listed above), and it doesn’t include time (which is #5 in the list above).
I’ve covered a lot in this massive series of articles on exercise intensity and muscle growth stimulation; probably more than anyone in history has ever done.
So are we finished? Have I told you everything you need to know about exercise intensity, as it relates to strength-training, weight-training and building muscle?
Not quite. There’s actually one more very important fact that you need to know about exercise intensity, that even the experts almost always neglect; or even don’t know about. I’ve alluded to it several times in these articles, and it’s this:
Whenever you do reps (repetitions) of any kind, the level of intensity constantly fluctuates; sometimes dropping down to zero. And that’s simply because whenever you perform reps, the “amount of muscular contraction that you generate per unit of time” constantly fluctuates; sometimes dropping down to zero. This is inevitable, whenever you do reps.
And that brings us to the fact that there are actually two types of exercise intensity that you need to know about, in order to build “maximum muscle in minimum time” from your workout sessions. There’s:
1) momentary or instantaneous intensity
2) average or overall intensity
So which one of those two is more important, for the purpose of maximum muscle growth?
That will be the topic of the next article in this series,
Comments” Questions? Care to agree or disagree? Feel free to do so!