Principles & Mechanisms of Muscle Building

In this article, I share 3 mechanisms (1) and 10 principles of muscle growth.

Do read through this article on ectomorph bodybuilding first, as it contains a technical explanation of muscular hypertrophy/the growth process which will help you understand this article better.

Understanding is key here.


1. Three Mechanisms of Muscle Growth


Muscle Growth Mechanism #1 – Muscle Tension

Weight lifting

This is otherwise also commonly known as progressive overload – loading your body with weights that it is not accustomed to so that your muscles will grow so as to adapt to the increased weight.

For a more technical explanation of the muscle growth process, check out ectomorph bodybuilding.

Do it in a gradual manner, starting from something you can handle first. Do remember that as you progress to heavier weights, it can get much more taxing on your body/central nervous system and recovery might take longer.

One tip that always works for me is to take a deload week (either low weight and reps or totally abstaining from the gym).

For beginners, focus on mastering the technique and posture above all else.


Muscle Growth Mechanism 2 – Muscle Damage

Muscle damage is also known as micro tears or trauma to your  muscle fibers.

Without the damage, inflammatory molecules will not be released and your immune system will not activate the satellite cells to repair your muscle cells (check out the previous link for the process).


Muscle Growth Mechanism 3 – Metabolic Stress


This is also known as sarcoplasmic hypertrophy.

You know metabolic stress has been attained when you feel the “burn” or “pump”.

Traditionally, sarcoplasmic hypertrophy has also been referred to as non-functional, as it is theorized to increase the size of muscles without increasing the contractile proteins (they produce force/strength) in muscle fibers.

This is a myth in two ways.

Firstly, you can’t achieve sarcoplasmic hypertrophy alone. Sarcomere hypertrophy will also occur, and this process increases the contractile proteins and thus strength (2).

Secondly, research has been showing that sarcoplasmic hypertrophy brings about increased hydration of the cell which may mediate a hypertrophic response and increase contractile hypertrophy (1).


2. Three Principle of Muscle Growth


Muscle Growth Principle #1 – Be Specific

Your ectomorph workout training stress has to be specific. In other words, focus is key here.

If you want to be good at running long distances, you run more. Similarly, to increase muscle mass, you have to lift heavier or do a higher volume of work.

Focus intensively on bodybuilding, don’t try to do everything else that may or not be related to bodybuilding or which may jeopardise your efforts.

Muscle Growth Principle #2 – Form and Technique



Form and technique are your foundations. They will help you achieve the maximum benefits from your workout.

The correct form and technique will also reduce your chances of injury dramatically.


Muscle Growth Principle #3 – Moderate Reps and Heavy Weights


The stress has to generated with moderate reps and heavy weights.

Few reps: 1-5
Moderate reps: 6-12
Many reps: >12

From Brad Schoenfeld’s review of the bodybuilding literature, he found that maximum gains in muscle hypertrophy are achieved by training regimens that produce significant metabolic stress while maintaining a moderate degree of muscle tension (1).

As such he recommends a rep range of 6-12 (to achieve metabolic stress) with heavy weights (to achieve muscle tension).

This is a good range to start, although I argue that everyone’s bodies are made up differently and will react to different training styles/sets (2).

Try out the different styles and find the most optimal one for you.


Muscle Growth Principle #4 – Short and Intense

Your ectomorph workout routine must be intense.

An intense workout for mass will make you exhausted, overload your central nervous system, and this in turn spurs the release of more testosterone and growth hormones which will do wonders to your muscle gains.

Note: This doesn’t mean training to failure on every single set!

Keeping the workout short (around 45 mins) will also ensure you do not burn too much calories and also leverage on the levels of anabolic hormones released (they peak at about the 27 mins mark).

Stay longer, and catabolic (muscle destroying) hormones are released increasingly.


Muscle Growth Principle #5 – Time under Tension

This principle is also known as time under tension, how long you put your muscles under tension.

A common mistake I witness is that gym goers tend to do their sets REAL fast. This is bad, why?

One, they don’t really work their muscles since the time under tension is short.

Two, there are three phases of muscular contraction – eccentric, concentric and isometric. By doing quickly, you don’t hit some of muscle fibers which can only be hit at specific phases.

1. Muscle mass accumulation phase (at least 40 seconds)

For instance, if 1 bench press rep takes you 4 seconds, then do 10 reps for 1 set. Most amateur gym goers don’t make sufficient muscle gains because they rush through sets, or because they have poor form.

2. Muscle mass intensification phase (at least 20 seconds)

In this phase, a shorter time period is due to heavier weights but fewer reps. This is to target the higher threshold motor units.


Muscle Growth Principle #6 – Adopt a Balanced Approach

Have you realized that most exercises done in the gym only require you to move forward or backward?

Like all things in life, success comes about with balance. Train all parts of your body, and train from all angles. This will reduce your chances of injury and you will be able to build muscles faster.


Muscle Growth Principle #7 – Don’t Neglect Dumbbells

Dumbbell work requires stabilization of the joint and exercises the muscles for greater ranges.

Definitely incorporate dumbbell work into your ectomorph workout routine if you haven’t done so.


Muscle Growth Principle #8 – Variety

charles poliquin

You have to vary the exercises in your ectomorph workout to break through weight lifting plateaus.

To recruit more muscle fibers and maximize muscle gains, do something differently! It can be anything, rep speed, exercise, numbers of sets, order of exercises, etc.

As famous strength coach Charles Poliquin once said, “A program is only as good as the time it takes to adapt to it”.

Muscle Growth Principle #9 – Recovery

You must recover before doing the next workout routine. Your muscles grow during this period, and not when you are in the gym!

And only when you recover can you progressively overload in your next gym workout routine.

Muscle Growth Principle #10 – Use a Training Journal


This is the most UNDERRATED principle of muscle building.

As they say, you can’t change what you don’t measure.

A journal will help you keep track of your progress, and this will help you to adjust your training schedule and weight loads accordingly.



(1) Schoenfeld, B. (2010). The mechanisms of muscle hypertrophy and their application to resistance training. Journal of Strength and Conditioning Research, 2857-2872.

(2) Cameron J. Mitchell, T. A.-V. (2012). Resistance exercise load does not determine training-mediated hypertrophic gains in young men. Journal of Applied Physiology, 71-77.


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