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The definitive guide to muscle hypertrophy part 1

Der definitive Ratgeber zum Thema Muskelhypertrophie Teil 1

Having looked at the basics of muscle hypertrophy in the first part of this article, in this second part of this article we will look at how different types of training and diet affect muscle hypertrophy.

How strength training affects muscle hypertrophy

To understand how strength training affects muscle hypertrophy, you need to understand the three primary triggers for muscle growth (29):

  1. Mechanical tension
  2. Muscle damage
  3. Cellular exhaustion

Mechanical tension refers to the amount of force produced by the muscle fibers. When you move weights, you produce two types of mechanical tension in your muscles: "passive" and "active" tension. Passive tension occurs when the muscles are stretched and active tension occurs when they contract.

Muscle damage refers to microscopic damage caused by high levels of tension in the muscle fibers. This damage needs repair, and if your body gets the right nutrition and rest, it will rebuild these fibers larger and stronger to better handle future tension.

(However, it is still not clear whether muscle damage directly stimulates muscle growth or whether this is merely a side effect of mechanical stress, but until this is definitively clarified, muscle damage still deserves a place on the list).

Cellular exhaustion refers to a series of chemical changes that occur inside and outside muscle fibers when they contract regularly (30).

Scientific research shows that mechanical tension is the most important pathway for muscle growth. In other words, mechanical tension produces a stronger muscle-building stimulus than muscle damage and cellular exhaustion (31).

These three pathways of muscle growth are related to what scientists refer to as the "strength-endurance continuum," which works as follows:

  • Heavy resistance training with lower repetitions increases muscle strength and results in a higher amount of mechanical tension and muscle damage, but less cellular exhaustion
  • Lighter resistance training with higher repetitions increases muscle endurance and results in lower amounts of mechanical stress and muscle damage, but more cellular fatigue.

Based on what you've just learned, which training style do you think would result in more muscle gains?

Yes, that's right, heavy training with low repetitions because it produces higher amounts of mechanical stress and muscle damage than lighter training with lower repetitions (33).

This has been demonstrated in a number of studies. One example of this is a study conducted by researchers at the University of Central Florida (34). In this study, 33 physically active men with some experience of training with weights were divided into two groups who completed the following types of training:

  1. High-volume, moderate-intensity training performed four times per week and consisting of four sets per exercise of 10 to 12 repetitions each (70% of 1 RM).
  2. A moderate-volume, high-intensity workout performed four times a week, consisting of four sets per exercise with 3 to 5 repetitions (90% of the 1RM).

Both groups used the same exercises (which included bench press, squat, deadlift and shoulder press) and both groups were instructed to maintain their normal dietary habits and keep a food diary.

After eight weeks of training, the researchers found that the group that had completed the high-intensity training had built significantly more muscle and strength than the group that had completed high-volume training.

The authors of the study cited two reasons for the heavier training being superior to the lighter training not only in strength gains, but also in gains in muscle mass:

1. the muscles were exposed to greater amounts of mechanical stress. High-volume training, on the other hand, caused greater amounts of metabolic stress.

2. a higher activation of muscle fibers. And this, in turn, resulted in greater hypertrophy over a larger percentage of muscle tissue (35).

For this reason, your primary goal as a natural trainee should be to get stronger, which is especially true for the primary basic exercises such as squats, deadlifts, bench presses and shoulder presses. In other words, the more weight you can move, the more muscular you will become.

How nutrition affects hypertrophy

You probably know that you need to eat enough protein to build muscle effectively. About 2 grams of protein per kilogram of body weight works pretty well for most people under most circumstances.

What you may not know is that you also need to consume adequate amounts of calories. Technically, 1 kcal is the amount of energy required to heat 1 kilogram of water at one bar of pressure by one degree and the relationship between the amount of calories you eat and the amount of calories you consume is known as energy balance.

Energy balance greatly influences your body weight and body composition. For example, if you supply your body with less energy than it consumes, you will generate an energy (calorie) deficit that will result in weight loss if maintained long enough.

However, such an energy deficit will also interfere with your body's ability to build muscle protein, which will slow or even stop your muscle gains completely (36).

The physiology at play here is quite complex, but to make a long story short, when you restrict your energy intake, your body goes into an energy-saving mode, prioritizing certain bodily functions over others (37). And since building bigger muscles is not essential for survival and requires a lot of energy, it is quite low on the priority list.

In addition, a calorie deficit can reduce anabolic hormone levels and increase catabolic hormone levels, causing a systemic shift from muscle gain to muscle loss.

Last but not least, a reduction in calorie intake almost always includes a reduction in carbohydrate intake, which will result in reduced performance in the gym. And this is the reason why it is commonly believed that you cannot build muscle and lose fat at the same time. However, this is not entirely accurate. If you have just started training with weights and are dieting or starting to train again after a long break from training, then you can achieve the holy grail of fitness: a body recomposition.

However, the fact is that you will never build as much muscle mass with a calorie deficit as you will with a calorie surplus. And if you're a slightly advanced or more advanced exerciser, you're unlikely to build any significant amount of muscle while dieting.

So if you want to build muscle as quickly as possible, you need to make sure you're not in a calorie deficit - and this applies regardless of your diet strategy and eating plan.

No matter what type of diet you follow - low-carb, intermittent fasting, carb cycling, vegan diet or whatever - if you're in a calorie deficit most of the time, you'll struggle to build muscle and strength. If, on the other hand, you make sure that you are in a slight calorie surplus most of the time, then it will be much easier.

How genetics influence muscle hypertrophy

For many people, the term "genetic predisposition" has a negative connotation as it is often associated with things you want to change but can't, and the bad news is that muscle hypertrophy is often one of those things.

We all have our hard limits when it comes to how much muscle mass we can build. However, unless you're looking to become a bodybuilding pro or a competitive fitness athlete, you can build more than enough muscle to achieve the look and performance you desire.

However, you may still be wondering how much muscle you can build. Well, there are many physiological variables at play here, but you can get a fairly accurate estimate of your muscle-building potential by analyzing your bone structure.

Scientific research shows that people with larger bones tend to be more muscular than those with thinner bone structure (41). They also tend to have higher testosterone levels and build muscle faster when they start exercising (42, 43).

This means that people with a coarser bone structure have a higher genetic potential for gains in strength and muscle mass than people with a more graceful bone structure. But what qualifies as having a coarse bone structure and where are you?

Well, the best indicator of your overall bone structure is the circumference of your wrists and ankles. All things being equal, people with larger wrist and ankle circumferences tend to be naturally more muscular and have a greater potential for muscle growth.

If you're like me and you don't need to measure yourself to know that you have a narrow bone structure, then that's no reason to give up. Anyone can build a significant amount of muscle if they eat right and exercise properly - and you don't have to build as much muscle as you might think to achieve a body you can be proud of.

Most men only need to build 7 to 10 kilos of muscle to achieve an impressive body, and for most this is closer to 5 to 7 kilos (or less). Once you've achieved this, simply reducing your body fat percentage is enough for better definition.

How cardio affects muscle hypertrophy

If you've been in fitness long enough, you'll have heard the following more than once:

If you want to be lean, weak and frail, do more cardio. There is some truth to this statement - cardio training can indeed impair muscle hypertrophy - but it's not so cut-and-dried.

Cardio training hinders muscle growth in two ways:

  1. In the short term, cardio can interfere with gains in strength and muscle mass by increasing fatigue, which makes it harder for you to push yourself harder in your workouts with weights.
  2. In the long term, cardio can impair your strength and muscle gains by interfering with cell signaling associated with muscle hypertrophy (44).

Good evidence for the first point can be found in a study conducted by scientists at the University of São Paulo (45). To see how performing cardio training before heavy weight training affects muscle growth, the scientists divided the subjects into three groups:

  1. The first group performed four sets of partial repetitions of squats with as many repetitions as possible at 80% of the maximum weight for one repetition (1RM).
  2. The second group performed 30 minutes of HIIT training on a cycle ergometer (one minute of easy riding followed by one minute at maximum effort), which was followed by the same leg workout.
  3. The third group performed 30 minutes of HIIT training with sprints (same protocol), followed by the same lower body workout.

After each training session, the scientists calculated the total volume of training with weights for each group and found that the first group (no cardio) performed better than the other two groups.

Muscle growth was not measured in this study, but based on much of what we have covered in this article, it is reasonable to assume that the first group would also have built significantly more muscle and strength if the study had continued over a longer period of time.

As for the second point - disruption of cell signaling - it should be mentioned that training with weights induces a cascade of cellular, genetic and hormonal changes to repair the damaged muscle fibers and make the muscles bigger and stronger to better cope with future training sessions (46).

Cardio training, however, stimulates a much different set of cellular adaptations that result in the muscle becoming smaller and more resistant to fatigue rather than bigger and stronger (47).

The exact mechanisms at play are beyond the scope of this article, but the short version is as follows:

Too much cardio training suppresses the normal levels of anabolic signals elicited by training with weights, which reduces gains in strength and muscle mass over time.

In other words, the more cardio training you do, the harder it is to become more muscular and stronger (48). Furthermore, the longer your cardio training sessions are, the more pronounced these effects will be (49).

However, it would be wrong to say that cardio has no place in your training plan. First of all, cardio has a number of health benefits that you are unlikely to get from strength training alone (50).

Secondly, there is some evidence that regular cardio training may help you recover faster between sets of your weight training sessions, which in turn may help you get more work done per session (51).

Thirdly, cardio training during muscle building could make it easier for you to lose fat during the subsequent definition phase (52).

The good news is that scientific research shows that you can minimize or even eliminate the negative effects of cardio training on muscle hypertrophy by following these steps (53):

  • Keep your cardio workouts relatively short (30 to 60 minutes max).
  • Do not perform too many cardio training sessions (three to a maximum of four per week)
  • Use less strenuous forms of cardio training such as cycling, swimming and rowing instead of running.
  • Do your cardio workouts after your weights workouts.
  • Do your cardio workouts on separate days (or at least a few hours apart from your weights workouts).

Stick to this plan and you should have no problem building muscle while incorporating cardio into your training program.

In the next part, we'll look at a 5-step plan that will help you put everything you've learned in the first two parts of this article into practice to maximize your muscle gain.


By: Michael Mathews

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