Muscle Hypertrophy

Muscle Hypertrophy: How Muscle Building Really Works

Big muscles and lots of power: Hypertrophy is the goal of most strength athletes. Hypertrophy training promotes muscle building by increasing the size of the muscle fibers – provided you workout properly.

To get started, let’s first create a solid foundation – before we start with the practical implementation, a definition of hypertrophy: This generally means an excessive growth of tissues and organs due to the enlargement of the cells, especially as a result of increased stress.

You can imagine hypertrophy as an increase in the thickness of individual muscle fibers: their cross-section increases without the body forming new muscle cells. The prerequisite is that the muscles are used beyond their normal performance level. For you this means: Quietly leave your comfort zone during training, whereby the safe execution and technique still have priority.

What happens during hypertrophy?

There is no growth without training stimuli – this is especially true for athletes who want to increase their strength. Means: Your muscles must always be slightly overtaxed during training so that they gain volume.

What exactly happens in the body after a set of squats, biceps curls and the like? The overloaded muscle gets tired and small injuries to the muscle fibers, so-called microtraumas, occur. The good thing: Our body is extremely forward-looking and efficient.

During the recovery phase after training, the muscle fibers are repaired by storing new proteins – the building blocks of the muscles.

The damage is not simply patched up, but the fibers are additionally strengthened so that the muscles are prepared for new loads of this kind. The body adapts to the training stimuli and muscle growth occurs.

How long does it take to grow muscles?

Through hypertrophy training, the body first learns to use more muscle fibers than usual. In addition, the so-called intramuscular coordination, i.e. the interaction of the individual muscle fibers, improves. For example, as soon as you do a push-up, as the training progresses, more and more parts of your biceps and triceps are active at the same time.

The result: the muscle cross-section increases. Of course, this doesn’t happen after just one training session. Depending on your previous sporting experience, it takes several weeks for your body to master the exercise techniques and movement patterns and to adapt. So be patient and don’t give up. Continuity is a crucial success factor in muscle building training.

As soon as the “learning phase” is over, the desired muscle growth begins. After a few workouts, usually eight to twelve, you will eventually notice that you are making less progress. Your muscle building stagnates. Don’t worry, this is completely normal.

Once your muscles have got used to a training period, there is no longer any reason for the body to adapt. Now you can, for example, work with more volume, increase your repetitions or vary the pace of the exercises to set new stimuli. In the next step, a new training plan will provide variety and new success.

The biggest influencing factors of hypertrophy

The greatest levers for hypertrophy are exercise and your diet.

In addition to growth stimuli from training and a corresponding diet rich in protein and carbohydrates, there are other factors that have an influence on muscle growth:

Genetics: The composition of muscle fibers

Everyone has two different types of muscle fibers, the distribution of which in the body is genetically determined: The red ones (type I) are resistant to fatigue, so they work continuously, but slowly. For example, they are used in cadio sports and endurance training with higher repetitions.

White muscle fibers (type II), on the other hand, are fast and strong. You are challenged when lifting heavy weights or when quick strength is required, for example during sprints or jumping exercises. If you have more of these type II fibers, you can build muscle more easily through hypertrophy.

The hormonal balance

When muscles are to grow, different hormones are involved. The hormonal balance depends on age and gender, but also on the individual diet and lifestyle.

The male sex hormone testosterone has a strong anabolic effect, i.e. it builds muscle mass. Because of their higher testosterone levels, adolescents and men can build more muscle faster, easier and more than women.

Insulin is a metabolic enzyme that makes cell walls permeable to important macro and micronutrients. These include, for example, essential amino acids that help you get the most out of your training.

Insulin-like Growth Factor 1 (IGF-1) is an insulin-like hormone. The messenger substance promotes tissue growth in the body and at the same time suppresses muscle breakdown – a win-win situation for hypertrophy.

In contrast to testosterone, the stress hormone cortisol is a catabolic, i.e. muscle-breaking hormone. It removes proteins from the muscles and converts them into glucose. What ensured survival thousands of years ago is now inhibiting our muscle building. So try to avoid too much stress if you want to support hypertrophy.

What is the difference between hypertrophy and hyperplasia?

Hypertrophy means that the cross-section of the muscle fibers increases. They gain in volume without new cells being formed. Hyperplasia, in turn, means that the number of muscle fibers increases. However, this process in muscle building is controversial.

Hyperplasia describes a process in the body in which organs and tissues enlarge as cells multiply. In strength training, this may occur as soon as the hypertrophic muscles become too large and their cells can no longer be supplied with sufficient oxygen. As a result, cells would divide. However, this phenomenon has not yet been proven in humans. When it comes to muscle growth, the majority of experts and sports scientists refer to hypertrophy.

Which workout is optimal for building muscle?

Your goal is hypertrophy? Then there is no way around a well-structured training plan.

In general, it makes sense if your plan is based on the seven training principles of load control: Your training load should be strenuous and you should increase yourself at regular intervals. Change the training method every now and then, integrate new exercises into your training and allow yourself enough breaks for regeneration. Plus: Train regularly and continuously.

To support your muscle building, you can also use three strategies for yourself: metabolic stress, mechanical tension and muscle damage.

All three mechanisms can be combined in training or you can concentrate on one of them. As? We explain that to you:


Metabolic stress

Have you ever been to the point where your strength just isn’t enough for one last push-up? That your muscles burn a lot during training or even after? This is a sign of metabolic stress.

The more repetitions and sets you do, the more your muscles will swell. The blood vessels shrink and less oxygen reaches the muscle fibers. The result: the body produces metabolic by-products such as lactate and creatine – we perceive this as burning.

Fortunately, the torture is not in vain, because metabolic stress has been shown to have a positive effect on muscle building.

Practical tip: Train with high repetitions (15-20 reps per exercise) at an intensity of 60 to 70 percent of your maximum strength.

Mechanical tension

Mechanical tension describes the resistance caused by weights. You need to use force to hold the barbell or kettlebell. This in turn irritates the muscle and forces it to adapt.

Practical tip: We recommend low repetitions (8-12 reps per exercise) with a higher intensity of 60 to 80 percent of your maximum strength. Increase the training volume from time to time so that you can just manage eight reps in the last set.

Muscle damage

Damaging the muscle sounds unhealthy at first. Muscle damage is absolutely in our favor if we want to build muscles. If you lift heavy weights during training or if your muscles are under tension for a long time, microscopic cracks appear in the muscle fibers.

The exciting thing about it: While you regenerate, the body repairs this damage and your muscles grow. The greater the damage, the longer this healing process takes – and the more uncomfortable climbing stairs the next morning becomes.

Practical tip: Train with a lot of volume and low repetitions (6-8 reps per exercise) at an intensity of 65 to 85 percent of your maximum strength. Also lengthen the eccentric phase, i.e. the speed when lowering the weights.

The greatest possible effect is obtained if you use all of the mechanisms mentioned and integrate them into your training plan.

As soon as the muscles get used to the training stimuli, muscle growth stagnates. It is therefore advisable to adapt your training plan every two to three months – for example with new exercises, more volume and different set, repetition and break patterns.

Summary: Muscle Hypertrophy

  • Hypertrophy or muscle hypertrophy is understood to mean the growth in thickness of muscle fibers, i.e. muscle building.
  • The prerequisite for hypertrophy is that the muscles are challenged beyond their usual level of performance during training – by the intensity of the load, the repetitions and the speed of the movements.
  • A well-structured training plan and regular increases in performance are the basis for building muscle. Orientate yourself to the seven training principles.
  • There are three mechanisms that athletes can harness to cause hypertrophy: metabolic stress, mechanical tension, and muscle damage.
  • Hypertrophy takes place during breaks in training. Sufficient regeneration is therefore essential if you want to build muscle.
  • Athletes can support muscle hypertrophy by eating a balanced diet high in protein and carbohydrates, avoiding stress.
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