- 7 August

Gaining muscle can be a challenging process. You’re putting in the effort, but not seeing your desired results. So what’s missing in your game of #gainz?

Our resident Resistance Bands Fitness Expert, James Grage, breaks down the science of #gainz with the Three Principles of Muscle Building (or Hypertrophy).  By understanding these principles, you will be better equipped to reach your fitness goals in bodybuilding and beyond.

To explain the principles of muscle building, let us first understand the significance of PROTEIN. In dry weight, our muscles are comprised of 70-80% protein, with protein acting as the main building block of muscles. When we create a buildup of proteins though protein synthesis, we call that ‘building muscle’.


Protein synthesis is defined as the process of which your body utilizes the amino acids in protein to build new muscle, get stronger, and recover from exercise. Throughout the day, your body alters between one of two states:

  • In an anabolic state, there is a build-up of proteins via protein synthesis – this is when we build muscle
  • In a catabolic state, our body is breaking down muscle as a source of fuel – this is when we lose muscle

When the buildup of muscle protein synthesis exceeds muscle protein breakdown, muscle building occurs. Think of it as balancing your financial budget: Income – Expenses = Balance.

With the understanding of our goal to build muscle is through triggering Protein Synthesis, let’s look at the ways to get us there.




The first trigger to muscle hypertrophy is Mechanical Tension, or the force that stretches or pulls a material. In this case, that material is our muscles, and that force can be free weights, machines, resistance bands, or anything else that gives us opposition.

How does mechanical tension build muscle?

Though there are several schools of thought for one specific method, something most experts agree on is this; when there is stress to the muscle, the body reacts by creating more proteins. This process makes the muscle stronger IF THERE’S ENOUGH STIMULUS.

You may think the greater (or heavier) the force, the more mechanical tension – which is true but only to a certain extent. To trigger hypertrophy, we must consider our X-Factor of Time Under Tension (TUT), in other words, how long you are holding that particular load or force.

For example, if you are doing a bicep curl that takes you one second to curl the weight up, one second to hold, and two seconds to lower, then that is a total of 4 seconds of tension per rep. With 10 reps per set, the total TUT would put you at 40 seconds (with the ideal TUT being 30-70 seconds per set to trigger hypertrophy).

This is why strict, disciplined form and rep speed is so important. Without the proper TUT, you are not triggering hypertrophy, no matter how many reps you do.

bicep curl down position/bicep curl under tension


If you’ve experienced “The Pump”, or that burning sensation moving through your muscles when you’re training, then you’ve experienced our second trigger to muscle hypertrophy, Metabolic Stress.

Metabolic stress is a physiological process that occurs during exercise in response to low energy that leads to metabolite accumulation in muscle cells*. Under normal circumstances, when our muscles have plenty of energy and oxygen, they work aerobically. On the contrary, when we perform short bursts of 1-3 minutes of high-intensity exercises, such as HIIT or resistance training, our muscles start to work anaerobically. This is due to a lack of oxygen. As a result, this forces the body to use a different energy pathway through glucose, with lactate and metabolites building up in the muscle cell. For this reason, our muscle cells begin to swell, giving us the physical sensation of what we call “The Pump.”

What triggers metabolic stress?

A primary trigger of metabolic stress comes through Occlusion Training, or restricting the flow of oxygen coming into the muscle. You may have seen this in the form of people wrapping their biceps when weight training. This wrapping approach is one way that can artificially trigger that “pump effect”. This is due to not enough blood going out through the blood vessels, yet a good deal of blood coming in through the arteries. While you don’t need to wrap your biceps exclusively, you can reap the benefits of occlusion training in the form of:

  • Proper Volume (Increase the reps / Increase fatigue)
  • High Interval Intensity Training (HIIT)
  • Proper Resistance at the top of each range of motion



Remember when you got after it on #legday and then had a tough time getting down the stairs for the next 5 days? It’s happened to the best of us! That prolonged soreness is a prime example of Muscle Damage.

Muscle damage occurs as a result of micro-trauma to a muscle during working. This micro-trauma causes the muscle to become inflamed, which gives us the physical sensation of “extreme soreness”. This introduces our third principle of hypertrophy: Muscle damage is necessary for building muscle.

NO PAIN, NO GAIN right? Well, yes and no.

When we discuss triggering protein synthesis and building muscle through muscle damage, there is a caveat. When protein synthesis is stimulated, muscle protein synthesis rates split between two processes: muscle growth and muscle repair.

Muscle growth is when we add a building block of protein synthesis to our wall of #gainz. While at the same time, when muscle fibers become damaged, we also utilize these blocks of protein synthesis for muscle repair.

These fibers can be damaged to a variety of degrees. On the low side, achieving our goal of micro-trauma. On the more severe side, overtraining and destroying the muscle. In this case, more is not always better. The key here is finding that sweet spot. There is such a thing as stimulating muscle growth with just the right about of micro-trauma without overtraining. Remember, our precious amount of protein synthesis is finite, and we want more of it going towards building muscle than repairing it. In other words: STIMULATE, DON’T ANNHAILATE.

What triggers muscle damage?

One of the best tools we have in our arsenal to stimulate muscle damage is through ECCENTRIC TRAINING.

A popular example of an eccentric training technique is through “Negative Reps”.
You may have seen this in the form of a spotter helping a lifter on the “up”, or concentric movement, with the lifter having slower, full control of the “down”, or eccentric movement.

This is beneficial for two reasons:

  1. We are 20-30% stronger on in an eccentric contraction vs concentric. For this reason, we can control a greater load on the eccentric movement. The greater the load, the greater the potential for muscle damage during those reps.
  2. When we perform eccentric contractions, the muscle is lengthening. Stressing the muscle in an elongated position is similar to stretching a rubber band. The longer we stretch our rubber band, the greater chance it has of damaging. Likewise, the more we elongate the muscle, the greater the chance for muscle damage.

Eccentric Bicep Curl / Concentric Bicep Curl

When you integrate these principles into your training routine, paired with a sustainable nutrition plan, you will be better armed to achieve your muscle-building goals. For a complete muscle-building 90-day program incorporating these techniques and more, take a look at James Grage’s 90-Day BUILD Program on TA2.