The Science Of Muscle Growth
The scientific secrets of muscle growth (train smarter, not harder)
The word hypertrophy gets thrown around gyms like everybody knows what it means. Most, would tell you that it means the growth of muscle mass. Whilst this is true, it’s not the entire story. Read on to discover the science of muscle growth. If you understand what muscle growth is and how it occurs, you are able to manipulate training variables to induce the mechanisms of muscle growth.
Hypertrophy is a term borrowed from medical sciences. It means “the increase in size or volume of cells”. In the medical world, this could be an increase in any type of cell not only skeletal muscle.
Muscle Growth Science
In the fitness and performance world, hypertrophy is used as an umbrella term for muscle growth. However, there are several types of muscle growth that can occur.
This results in an increase in cell size and volume due to an increase in sarcoplasmic fluid inside the cells with no increase in muscular strength. The increased size accommodates for a higher glycogen storage within the muscle which, increases the muscle’s resistance to fatigue. This is a typical goal for bodybuilders because of the increased size of the muscle.
Hyperplasia or else, Myofibrillar Hypertrophy
This results in an increased number of cells. The actin and myosin filaments that make up the structure of your muscle are multiplied resulting in an increased number of cross sectional fibres able to produce force. This is a typical goal for weightlifters and strength athletes because of the increase in strength without the increase in mass.
THE VIDEO: The Scientific Secrets Of Muscle Growth (Train Smarter, Not Harder)
The mechanisms of muscle growth
Strength training generally creates a combination of both types of muscle growth with an increased resistance to fatigue and force production. There are three mechanisms to induce these two types of muscle growth.
During contraction, the muscle cells use glycogen as fuel to create ATP. The ATP molecule binds to the actin filament and this creates a contraction. This is created without the use of oxygen which, creates an ischemic condition within the muscle cell, an oxygen deficit. This metabolic stress induces an increase in sarcoplasmic volume, hypertrophy, so that it has a higher resistance to fatigue, increasing the size of the cells.
It’s the amount of tension placed upon a muscle unit. It can be increased by creating the highest amount of force either by increasing load or the speed of a contraction. As a result, the highest amount of motor units get recruited as well as muscle mass stimulating protein synthesis and therefore, growth.
With each repetition, the bonds between actin and myosin filaments break down. The damage within the muscle fibres induces the growth of more cells creating more cross-sectional filaments which, increase the force producing capacity of the muscle.
During any type of resistance training, if the imposed stress is high enough to elicit growth, there will be a contribution from each mechanism but never one mechanism in isolation.
For example, if we think about the mechanisms in use during traditional hypertrophy training (3sets x 8-12 reps, 1minute rest), we are doing a high volume of reps at around 60-75% 1rm. This type of training creates a high metabolic stress, moderate amount of muscle damage and low mechanical tension.
On the other hand, if we look at a typical strength training session, (5sets of 3 reps, 3 minutes rest), the muscle damage is high, the mechanical tension high to moderate but the metabolic stress low.
Use all the mechanisms for best results
If you are looking to build muscle and improve your strength and size, remember that there is more than one type of muscle growth and more than one mechanism to elicit growth. If you plan your training to focus on one mechanism, you will get the strongest response from that mechanism, however, the other two mechanisms will still be in play.
The number one rule to remember is that progressive overload induces growth. Gradually increasing your overall work done, elicits a response from one of the three mechanisms. Gradually increasing the number of sets and reps that you are performing at a given intensity, increases the metabolic stress and muscle damage. Gradually increasing the weights you are using, increases the mechanical tension and slightly increases the muscle damage. Manipulating the type of contraction and tempo of your movements can increase the amount of muscle damage you elicit during your training. For best results, your training should incorporate both high metabolic stress and mechanical tension. The muscle damage will increase as you progress with the other types of training.