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Everything you need to know about muscle hypertrophy


We go to the gym for different reasons, to gain muscle, strength and/or lose fat.

Whatever your goal, you need to know how hypertrophy works, its mechanism and how to use this knowledge to optimize your training.

What is hypertrophy?

Simply put, hypertrophy means "to grow". From a scientific point of view, hypertrophy describes the growth or enlargement of any organ or tissue. In the world of bodybuilding and fitness, hypertrophy refers to the process by which exercise creates and promotes muscle growth.

Hypertrophy occurs as a result of training if combined with proper nutrition, but it requires a secret ingredient: time.

Progressive overload: the key to hypertrophy

You've probably heard the story of Milo de Croton, he was an ancient Greek wrestler who developed enormous strength qualities in a unique way. He was the originator of one of the basic theories of strength and conditioning, known as progressive overload.

The story goes that one day, a calf was born near Milo's house. The wrestler decided to lift the little animal onto his shoulders. The next day, he came back and did it again. Milo continued this strategy for the next four years, putting the calf on his shoulders every day as it grew, until he was no longer lifting a calf, but a four-year-old bull.

The key principle to remember from The Tale of Milos is to start lifting light with lots of reps and gradually add weight as you progress. It's also important to be consistent, to allow your body to adapt.

What happens in practice? Basically, when your muscles are confronted with challenges they're not used to, such as strength training, they undergo trauma. This trauma is repaired in the hours and days following the workout and, in the process, your muscles rebuild stronger - and bigger - than they were before.

The 3 factors of muscular hypertrophy

Most scientific publications have come to the conclusion that muscle hypertrophy is the result of three main factors:

- Mechanical tension

- Muscle damage

- And metabolic stress

Let's take a closer look..

1. Mechanical tension

Mechanical tension is the tension that muscles receive when a weight is lifted. It is created by using a heavy load and performing exercises with full amplitude for a certain period of time. It is achieved in so-called short sets, and is the most important factor in hypertrophy.

Strength training therefore creates mechanical tension in the muscle. The more time spent under load, the greater the mechanical tension exerted. For hypertrophy to occur, sufficient time must be spent under tension.

However, tension alone will not induce maximum muscle growth. In order to stimulate hypertrophy correctly, the muscle must also be stretched to an adequate amplitude.

To sum up, if you want to promote muscle growth, you need to lift heavy weights, in a controlled manner, with full amplitude for a certain period of time. Simple enough, isn't it? Using good amplitude when exercising is also very important for building muscle and maintaining good flexibility. This activates more muscle groups and improves overall exercise efficiency.


2. Muscle damage

Muscle damage is an essential component of the hypertrophy process. These injuries occur during resistance training, largely as a result of eccentric and concentric contractions. The resulting muscle soreness is a very common sensation experienced by athletes after training. It's the result of micro-tears in the muscles following damage.

Both types of contraction cause muscle damage, but eccentric contractions (when the load is held - negative phase) cause more damage to the muscle than concentric contractions (when the load is contracted). This is why bodybuilders slow down the load in the negative part, or incorporate "negative" repetitions (intensification technique) into training programs. The appearance of muscle damage triggers physiological processes which then activate protein synthesis and the rebuilding of damaged muscles.

Exercise can produce these muscular lesions via a mechanical action, but also through an inflammatory process triggered as a result of these movements.


3. Metabolic stress

Lifting heavy weights to create mechanical tension works to create hypertrophy. But it's also accepted that lifting moderate to light weights, with more repetitions, i.e. long, light sets, also promotes muscle growth.

Those who do weight training or other sports have probably experienced the "burn" and "congestion" that comes with long, light sets combined with short rest times.

A number of things happen during these sets. Metabolic stress generates hypertrophy, mainly by inducing fatigue, which results in an accumulation of metabolites in the muscle fiber, such as lactate, hydrogen ions, etc. The resulting metabolic stress has an anabolic effect, leading to a hormonal response. The resulting metabolic stress has an anabolic effect, leading to a hormonal response. This increases the secretion of several anabolic hormones such as testosterone, growth hormone and insulin.

Metabolic stress therefore has a similar effect to mechanical tension on muscle hypertrophy. Mechanical tension and metabolic stress ultimately work together, but not in opposition to each other.


What to do with this information?

Hypertrophy occurs as a result of a number of variables - mechanical strain, muscle damage and metabolic stress. When combined, they have a very "anabolic" effect on the body. This translates into increased levels of testosterone and growth hormone, which play an important role in the synthesis of proteins needed for muscle repair and growth.

For results to appear, you also need to eat properly. Remember that the three cornerstones of muscle building are training, rest and diet. And genetics, of course. However, there's not much you can do about it.

Weight training makes you more muscular and stronger. You trigger complicated signaling mechanisms in your muscle cells when you lift weights. These signals tell your body to build muscle mass. After each workout, your muscle protein synthesis increases to the point where it exceeds muscle protein breakdown. Over time, this translates into significantly greater muscle mass and improved muscular strength.

In short, while your workout works for your muscles, it can't do everything on its own. If you don't provide sufficient energy and nutrients from your diet, your efforts will be in vain.

Once you've clarified this, how do you apply these principles to your bodybuilding training?

Easy. The easiest way is to mix long, light sets with short, heavy ones. Because you can build muscle with both. In practice, you can include them in the same session or separate them (heavy VS light session). If you mix them in the same session, start with short, heavy sets with a normal rest time, then add longer, lighter sets at the end of your program.

Hypertrophy VS strength: what's the difference ?

Strength training and hypertrophy training don't necessarily have the same objective or result. Most people think that bigger muscles produce the most strength. However, when comparing bodybuilding to strength training, strength-training muscles can have better overall muscle fiber quality without necessarily being as bulky.

Although greater muscle mass can provide a certain advantage in terms of strength, performance goals and training approaches differ depending on the desired result: more muscle mass or more strength.

In practice, if you start a bodybuilding program, you'll build muscle and strength at the same time. After that, you can choose either a strength program or a bodybuilding program, depending on what you're aiming for.

In terms of training, if your aim is simply to gain muscle, use a moderate load: 65 to 80-85% of your maximum on one repetition (1 RM), 6 to 12 repetitions per set, 1 to 3 sets per exercise. Rest should be between 30 seconds and 1 minute 30 seconds between sets.

For a strength objective, proceed as follows:

- For beginner to intermediate athletes, experts recommend training with loads corresponding to 70 to 80% of 1 RM, at least 6 repetitions per set for 1 to 3 series. 2 to 5 minutes rest between sets.

- For advanced training, 85% of 1 RM for at least 3 sets to maximize muscle strength. At least 6 repetitions for each set, with 2 to 5 minutes' rest between each set.

Posted in: Bodywork