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In the fitness world, we always hear about “shocking the muscle” and how it is needed for muscle growth. When people say this, they are referring to the fact that we must consistently change the routine we engage in order to stimulate muscle growth. This statement acknowledges that the muscle is smart, it has “memory” and will adapt to any and everything we throw at it. As a result, people change their routines sporadically essentially gaining no traction and even if they do gain some sort of traction and they eventually hit a wall. The rhetoric surrounding this phrase of “shocking the muscle” is so misleading to some people that I thought I might clear some things up by touching on the basics of the principle of progressive overload and hopefully contribute to the death of the term “shocking the muscle.”

  • Neuromuscular adaptation
  • The Principle of Progressive Overload: You’re Not “Shocking The Muscle.”
  • Four Ways to Overload

Neuromuscular Adaptation

When we begin any type of training, we are clumsy, slow, weak and easily fatigued during the first session of training. The following session we get a little more coordinated, faster, stronger and our stamina increases. The following session we are spot on with our coordination, speed, strength and stamina, our times to complete a certain circuit or movement has improved significantly throughout the weeks and we feel like an expert. What causes us to adapt to the training so fast? Our nervous system is amazing. It has the ability to adapt to stresses placed on the body over time and if we train it hard enough, we have the ability to push it to heights as high as we can imagine. The thing is that it quickly adapts to anything we throw at it so we must outsmart it and consistently place new challenges in front of it.

There are two main components that make up neuromuscular adaptation: Motor neurons, neuromuscular facilitation or “muscle memory.”

neuromuscular junction

Motor neurons: Motor neurons are nerve cells that start from the spinal cord/central nervous system and stop at the muscle fibers in a spaced called the neuromuscular junction. At this junction, a neurotransmitter called “acetylcholine” is secreted and causes the muscle to contract due to signals sent from the brain. This signal, motor neurons and neuromuscular junction makes up what we call the “efferent pathway.” The efferent pathway is responsible for involuntary(breathing), and voluntary(strength training) muscle contractions. Every time we work on a new movement in strength training, the brain has to tell the muscle fibers via the efferent pathway how to contract in order to perform the movement.


Neuromuscular facilitation: This is a means by which the neuromuscular system learns motor skills, hence why we never have to re-learn to walk everyday. This is also called a motor engram. When the brain consistently sends signals to the muscle, eventually the pathway is ingrained into the system and therefore, little to no effort is needed in order to maintain the ability to execute the movement.

With these two great components built into our beautiful, complex bodies, we have the ability to become increasingly skilled at whatever we attempt. Overtime, the nervous system comes up with increasingly efficient ways to fire motor neurons in order to recruit the appropriate muscle fibers to perform a lift. Frequency of the lift performed dictates how efficiently the muscle fibers will be recruited and fired.

The Principle of Progressive Overload: You’re Not “Shocking The Muscle.”

This is the term that is preferred over “shocking the muscle.” Using the term “progressive overload” implies a better understanding of what is happening to the body on a neuromuscular level when it undergoes rigorous strength training. The body only understands one thing when it comes to getting stronger, volume. There are many ways to get bigger and stronger, I’ll talk about four that I personally use in regards to volume. They are simple and basic concepts that can be applied to any routine without running the risk of developing a short attention span due to the sporadic switching of movements.

Four Ways to Overload 

  1. Increasing the number of reps
  2. Increasing the number of sets
  3. Increasing the amount of weight
  4. Increasing frequency of training

These are just four ways to overload the neuromuscular system and stimulate growth via volume. Notice I didn’t include changing the movements. Maybe changing the movements will have some sort of overloading effect, I don’t know, I’m not a scientist, but I do know for sure the aforementioned ways work, especially when built around The Big Four.

Before we go into these four ways, what is volume? When it comes to strength training, volume is calculated by multiplying the number of sets done, by the number of reps done in the set(s) by the weight. Volume is the accrued amount of pressure the body feels from the stimulus of strength training.


for a particular movement, 4 sets of 8 reps @ 225lbs/102kg = 7,200lbs/3266kg, 7200lbs/ 3266kg is the total volume done for a particular movement that day. If we wanted to get meticulous, we can do total volume for the session which would be the sum of the volume for all of the movements completed that session. Changing each of the components that constitute how to calculate volume influences the volume.

Increasing the number of reps

Lets use one of the greatest mass builders in history as an example to demonstrate the power and logic behind progressive overload, the squat. Say we have a beginner, his name is Joe and he is able to squat 135lbs/61kg for 3 sets of 6 reps on his first leg session. He pushes through, grinding his way through this intense squat session barely hitting these numbers. The next squat session he bangs out 3 sets of 7 reps. Did he progressively overload? Lets do some math.

On his first session Joe hit 3 set of 6 reps @ 135lbs/61kg = 2,430lbs/1102kg

On his second session he hit 3 sets of 7 reps @135lbs/61kg = 2,835lbs/1286kg

Controlling for amount of sets, weight and maybe even the color of his pants on both of those sessions, the only thing he changed was the amount reps he did. He most certainly progressively overloaded and therefore has gotten stronger from one session to the next just by increasing the amount of reps he did on each set.

Increasing the number of sets

Now, our friend Joe could have went about it another way by increasing the number of sets he performed. From session to session he could have went from:

3 sets of 6 reps @135lbs/61kg = 2,430lbs/1102kg


4 sets of 6 reps @135lbs/61kg = 3240lbs/1450kg

In this case, he moved more volume from session to session therefore he progressively overloaded and stimulated growth.

Increasing the amount of weight

This probably the most popular way to progressive overload because of the amount of ego involved. People love to brag about how much weight they can move. If our friend Joe is like any of these people, he would want to increase the amount of weight he does each session. (It also depends on what Joe is training for, if he is training for a powerlifting meet or a sport involving moving the most amount of weight at one time then this is the appropriate method to use combined with the other methods for accessories but that’s for another topic. In this article we are going to stick with dealing with progressive overload in regards to showing how we can stimulate growth.) From session to session it would look something like this:

3 sets of 6 reps @135lbs/1102kg = 2,430lbs/1102kg


3 sets of 6 reps @140lbs/64kg = 2,520/1143kg

In this case, he moved more volume via adding more weight from session to session. In these above examples so far, there were some apparent degrees in how the numbers changed from one method to the next. The most stressful on the body would be to increase the amount of sets done each week but then again these are theoretical examples and the numbers reflect that.

Increase frequency of training

I do not know many people who train this way but I can imagine this would be a method that is tailored to the long game when it comes to strength training, someone who has been training for five years or more. Increasing the frequency of training or even just one lift is a way to progressively overload. We can imagine that someone who squats once a week, every week for a year at specific numbers can then start to squat two times a week every week for the next six months to a year or so and then increase from there to squatting 3 times a week for 6 months to a year. Again, I do not know anyone who really trains like this unless they are doing some sort of full body routine.

What we’ve learned

Today we learned that neuromuscular adaptation is the body’s way of adapting to external stimulus placed upon it. The two components of this beautiful mechanism consists of the use of motor neurons and neuromuscular facilitation in order to learn and execute a lift in the most efficient way possible. Knowing this information we use the principle of progressive overload to keep the body from plateauing in strength. Progressive overload allows for us to get stronger overtime, increasing our strength over time and developing muscle maturing overtime. We learned four ways to take advantage of progressive overload: increasing the amount of reps we perform, increasing the amount of sets we perform, increasing the amount weight we use and increasing the frequency of sessions throughout the week. Most importantly, we learned that using the term “principle of progressive overload” is a better, more appropriate term to use. Rather than saying “shocking the muscle” which makes us sound uncouth and barbaric, we say “the principle of progressive overload” because it makes us sound all cool and sciencey!

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