New Muscle Growth Theories: Part Two!

As we learned last month, there is an extensive amount of activity involved in the growth process. The muscle damage theory alone is not solely responsible for muscle growth but as noted it is the most widely supported. Learn why.
Note: This is part two, click here for part one!

As we learned last month, there is an extensive amount of activity involved in the growth process. The muscle damage theory alone is not solely responsible for muscle growth but as noted it is the most widely supported in spite of some of its shortcomings. The muscle damage theory leaves gaps in the issues regarding hypertrophy stimulus but what we will see in the Substrate Accumulation Theory is that some of these holes will be filled.

It should be noted again that either theory by itself does not give the complete picture of muscle growth. However, when the combination of both theories are taken into consideration we end up with a much more complete understanding of the growth mechanisms. When we examine the Substrate Accumulation Theory we find that its basis is soundly related to the Muscle Damage Theory but extends the interaction and subsequent reactions that extend our understanding deeper into the post activity involved as a result of the damage that occurred during the exercise.

The Substrate Accumulation Theory

The Substrate Accumulation Theory states that through intense muscular exertion (such as heavy weight training); there is a resulting accumulation of metabolic by-products. These by-products cause a release of other various hormones. The effects of these hormones sets up the perfect environment to stimulate muscle hypertrophy.

What really happens when this theory is applied is really quite enlightening. We would all agree that heavy exertion, like that involved in weight training, requires a great deal of energy. In order for our bodies to meet the demand of this effort it accelerates the metabolism to fuel the muscular contractions. We experience an increase in respiration and heart rate. Our body temperature increases along with our blood pressure.

As the muscles fatigue, our energy levels decrease and lactic acid begins to build in response to the exertion. These are the obvious physical and metabolic changes we experience. We also know that anything that requires an action has a corresponding reaction. In this case, it is the generation of by-products and other chemical substances that inter-react in a symphony of complexity throughout the central nervous system.

The most predominant by-product that comes to mind is lactic acid. There have been studies done recently that appear to support, at least in part, the Substrate Accumulation Theory. They show that lactic acid has the ability to stimulate the production of testosterone. It is also speculated that there may also be a corresponding effect on the release of growth hormone. Through intense effort in addition to the stimulation of the central nervous system there is also a release of Beta-antagonists from adrenaline hormones like epinephrine and norepinephrine.

In several studies it has been proven that Beta-antagonists can be potent anabolic agents. You see where this is going? The interaction of the resulting chemical production that was induced during exercise has a domino-like effect on chemical changes that resulted directly from the muscle damage and the subsequent production of by-products that followed.

One of the important points here is that there has to be sufficient stimulus of the muscle in order to trigger these reactions. The body will respond only if the stimulus intensity is high enough to produce the activation of the growth mechanism to induce the muscle hypertrophy. When we take a look at the training methodology and techniques we find that it is the combination of both the Muscle Damage Theory and the Substrate Accumulation Theory that produce muscle hypertrophy.

My belief is that given adequate stimulus to cause muscle damage there is always the adequate creation of by-products that generate the corresponding chemical reactions. There are certain training techniques which have a predominant basis which may favor one theory over the other but keep in mind that both theories work together to produce muscle growth. Let's take a closer look at a few training techniques and how they might apply to these theories.

Eccentric Contractions

An eccentric (negative) contraction involves the slow and strict stretching of a muscle under resistance. An example would be slowly lowering the weight during a set of curls. We need to examine the effects of the muscle contraction at the filament level of the muscle, specifically, the relationship between the actin and myosin filament. Examining the muscle at this low level of activity we would see that the lengthening of the muscle as the filaments slide over each other is much more damaging than the prior concentric (shortening) contraction.

The muscle is designed to produce its force during the concentric (positive) phase of the contraction, not the eccentric. I bet you've heard that in order to get the most out of a rep you should follow the 2-4 rule. Come on now, you remember this from the beginning days of bodybuilding. Wasn't it one of the hundreds of Weider Principles, like Weider Principle #2 or something?

The principle stated that when performing a rep one should take two (2) seconds on the positive (concentric) phase of the muscle contraction and four (4) seconds on the negative (eccentric) portion. The emphasis here is to promote the greatest amount of muscle damage.


Plyometrics is a form of training used much more in the development of strength and power. Plyometrics involves the rapid contraction of the muscle immediately following an equally rapid stretch. The theory behind this training is that when rapid contractions are performed immediately following a stretch, there is a greater recruitment of muscle fiber as a result of what is called a stretch reflex. The stretch reflex causes the muscle to actually contract as a result of the preceding rapid stretch.

The addition of the voluntary contraction induced through the reflex action itself increases the amount of force in the contraction above that of a normal contraction. An example would be to take the vertical jump.

If the vertical jump is performed after a preceding approach step, the height is greater due to the rapid stretch from the approach step than it would be if the vertical jump were performed by itself. This type of training results in mostly muscle damage.

Inverted Pyramids (Drop Sets)

Inverted Pyramids are performed by selecting a weight you can do a higher number of reps with and upon failure; you drop the weight usually twenty-five (25) to fifty (50) percent and immediately perform another set to failure. This can be done in a singular drop or in multiple drops depending on your preference.

The idea here is to bring the muscle to failure several times to recruit more fibers, which results in increasing the production of by-products and lactic acid. Remember what we said earlier about the anabolic effect due to chemical reactions on the release of testosterone and growth hormone release. The major emphasis of this training technique is to maximize the stimulation of the metabolism to produce the greatest metabolic release of hormones.


This training technique was given to us by Mike Mentzer. It was developed to increase training intensity through one set of eight (8) to ten (10) reps at nearly your one rep maximum. The set is performed with a weight that is approximately ninety (90) to ninety-five (95) percent of your one rep maximum. One rep is performed at this weight, followed by a 15 to 20 second rest followed by another rep. This continues until you have performed eight (8) to ten (10) reps.


Calculate Your One-Rep Max (1RM)

Weight Lifted
Reps Done

= One-Rep Max

95% 1 RM
90% 1 RM
85% 1 RM
80% 1 RM
75% 1 RM
70% 1 RM
65% 1 RM
60% 1 RM
55% 1 RM
50% 1 RM


Enter the amount of weight you lifted (Lbs/Kg) and the number of reps you completed. Your One Rep Max (1 RM) will appear at the bottom left, and your various percentages of 1 RM will appear on the right side.

The really cool thing is that this is a great way to maximize the intensity for the greatest size and strength benefits all in only one set. This technique incorporates the greatest amount of muscle damage with a very high production of metabolic by-products.


This training technique incorporates several different exercises for the same body part into one set. This is a great way to increase intensity in a workout as well as shorten the duration of the workout at the same time. Sets for the particular body part are performed back to back with no rest in between sets. If you were training triceps, you might perform a set of close grip bench presses immediately followed by lying triceps extensions or triceps press-downs.

Several different exercises for the same muscle may be incorporated in this fashion if desired. It should be mentioned that this type of training could lead to overtraining if performed too frequently. The main focus of this technique is to stimulate the metabolism to chemically induce the greatest release of chemical producing hormones.

As we have seen through the discussions of both of these theories there are several different factors which are involved in the production of muscle growth. The Muscle Damage Theory coupled with the Substrate Accumulation Theory offers insight into the complex and multi-faceted processes, which are involved in the growth of muscle tissue beyond normal levels. Through studies that gather data such as this, researchers can gain a more complete understanding of the many different functions and changes the body undergoes.

These adaptive processes and how we can stimulate the growth mechanisms to work in conjunction with the natural biological and physiological mechanisms to produce hypertrophy in muscle tissue is an interesting yet complicated process. We are in an era that is seeking the answers to questions like these that will hopefully result in a more complete understanding of what makes us tick. The incorporation of different training techniques into personalized protocols requires patience and persistence.

Although bodybuilding is a science, self -experimentation and an in-depth understanding of theories like these provides greater insights into the workings of the human body and how we can best utilize its many remarkable capabilities and complexity of function to further our physical health and muscular development.

The only limits you have are those that you perceive and place upon yourself.

Note: This is part two, click here for part one!

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