Each of my posts starts with gathering source material. I hope that it will be an added value for both you and me, as I hope as a trainer, I will learn something new as well:) Apart from university textbooks and scientific articles on a given topic, I also do some research on the Internet out of curiosity. I was quite surprised when I read that stretching exercises should last a maximum of 15 seconds. And it's done! A strange idea, isn't it?

In the post below, you can read about stretching and flexibility training. I will try to introduce you to:

  • the difference between active and passive stretches.
  • why we need mobility
  • healthy stretching practices.

How do muscles work and why is passive stretching not the best?

Stretching is a specific form of training where understanding how muscles work is crucial for proper training selection and plan. A lot of you ask me: "Why does stretching hurt?" I answer that the pain is the result of our muscles tearing and my students are usually surprised. I will explain what muscle tearing is in a moment. Due to their structure, muscles can contract. They are made of small muscle fibers that can be compared to threads.

 Due to the type of fibers, muscles can be divided into:

  • type I - or "slow-twitch" muscles contract slowly and are more resistant to fatigue;
  • type II - or “fast-twitch" muscles contract quickly, but unfortunately they also tire faster.

During training, the slow-twitch muscles start working first, then the fast-twitch muscles follow suit. It doesn't matter if it's stretching, mobility training or how physically fit you are. The first type of muscles is always involved. What do we need this information for? To be able to stretch safely, you need to be aware of how your muscles work. All the muscles in the human body have the ability to contract or tense in different ways. Professionally, muscle contractions are called dynamic contractions. They are divided into 5 types.

Dynamic contractions:

  1. Concentric. They rely on a muscle "shortening” aimed at causing movement, e.g.: biceps femoris when preparing to jump.
  2. Eccentric. They rely on "lengthening" the muscle. Example: biceps femoris slowly disintegrating to side splits.
  3. Isometric. Otherwise called static contractions. The muscle tightens but does not move. Example: squeezing and relaxing the buttocks while sitting in the splits.
  4. Isotonic. Any contraction that changes the length of the muscle. This group includes both concentric and eccentric contractions. Isometric contraction is the opposite of isotonic contraction.
  5. Acoustic. Contractions having the characteristics of both isotonic and isometric contractions. This means that when performing a given activity, both types of muscle tension occur. Example: running, walking.

Phew, a lot of theoretical knowledge! Now let’s put it into practice. Using muscle contractions is essential during flexibility training. Unfortunately, still one of the most popular ways to stretch is the so-called passive stretching. It mainly consists of sitting in a given position for a certain period of time or being pulled by a trainer who sits on us when we are in the splits. Be careful with that. Passive stretching is based on eccentric muscle contractions, i.e. their lengthening. The current state of knowledge shows that this is not the best way to expand our ranges of motion, especially when it occurs alone, without other types of contractions.

Passive stretching is achieved by:

  • by entering the maximum range of motion and waiting for a certain period of time,
  • someone pulls us down, but we do not do any muscle work,
  • as a result, the muscle is elongated (eccentric contraction) and the muscle fibers are gradually "torn".

Relax, muscle tearing is not yet alarming. Muscle tissue has regenerative abilities. As a result of tearing, the tissue will build up in such a way that it increases its quality and length. Exactly the same thing happens during strength training! Does this mean professional weightlifters are incredibly stretched at the same time? No, it's not that simple.

Let's go back to the types of muscle contractions. During passive stretching, when we are straining the muscles, we are acting on an eccentric contraction. Our goal then is to stretch, for example, the leg by lengthening the muscle, and not increasing the strength by building up. A pictorial example is the slim legs of artistic gymnasts. Especially those from Russia and Ukraine often have an extremely small and flaccid structure - this is due to the use of mainly passive stretching, unfortunately many times by force.

Why can passive stretching be harmful?

  1. We do not enter the maximum scope by ourselves. When it happens in a form of our trainer pushing us, our body is often not prepared for it.
  2. The muscle is stretched but does not do any work. We are only expanding the passive scope in which we have no strength. Later, it often turns out that in elements where we do not press against a pole, a hoop or a silk - we cannot reach a full split, even though we sit in it on four yoga blocks on the ground!
  3. We lose the ability to maintain the tension of a given muscle in the maximum range of motion, which is associated with greater flaccidity. Ultimately, we also lose stabilization.
  4. By merely stretching passively, we don't stimulate our nervous system to work. By putting on regular loads, the body calms down the pain associated with passive stretching and stops noticing it. This can result in insensitivity and muscle tearing.

So is passive stretching wrong and should be avoided? 

No. Passive stretching can be detrimental if it is not balanced by other types of training. It is worth mixing it with mobility exercises, i.e. those that involve strength work of the muscles during stretching and work in the maximum range of motion. It also works the other way around - mobility training alone without passive stretching will not bring you as good results as with it.

So what is the difference between mobility and stretching?

You can see it fantastically on @robinmartinyoga ’s Instagram. Robin is a world-class yogi and practically her entire profile is devoted to showing the differences between passive elements (that is, those that are based on passive stretch) and active elements that are based on mobility.

What is mobility?

Mobility is the use of force in the maximum range of motion. Whenever I introduce this term, I tell my students - if we are able to do the splits, we should be able to hold it - standing, without using our hands. Similarly - we should be able to gradually slide into and get up from the splits. This is what it is all about. Mobility is the missing link between strength training and flexibility training - and unfortunately still little is known about it. Keep in mind that mobility training is very often associated with stabilization training (another underestimated aspect in aerial training). This, in turn, is crucial for our health and general condition, especially in the next dozen or so years or when we retire. However, we should remember that mobility training does not fully coincide in its assumptions with stretching training. Ultimately, they have slightly different assumptions and the truth is that the best results will be achieved by using both techniques: effective "strengthening" of our acquired ranges and their gradual deepening by passive stretching, but also force, using body weight or external weight.

I get a lot of questions: "Why am I not seeing progress despite stretching every day?" Let's say once and for all: everyone is different. There are people who will have better ranges after one flexibility training than others after six months of work and those who after 5 push-ups will be stronger than, for example, me - after 2 strength training sessions. Our biological capabilities vary. If a given training technique does not work, you have to look for a more effective one. I have to warn you! If you have only done flexibility training without mobility elements, your flexibility will decrease in favour of strength. If course, if you begin to stretch, your strength will decrease. That is why it is so important to look for your own recipe on how to find perfect balance between mobility training and passive stretching.

By the way, I know one who has been stretching their splits for two years without having sat in them even once. And guess what? It is impossible to do the splits without sitting in the splits ;) Mobility alone - is also not a good solution. Remember! Your own balance is key to success.

Emilia Dawiec