The SAID Principle: How to Design an Effective S&C Program

Physical training can change the body. Over a long period of time, experts in physical exercise and training have been shaping the types of loads, training frequency, volume or intensity, among others, to offer the population the perfect combination to achieve a high level of sport. We know that if the organism is “threatened” by external stimulus, it adapts and prepares itself in case it gets that stimulus again. This adaptation is what improves our muscle mass, our cardiovascular system or our bone mass. When coaches design a strength and conditioning program, they consider all these variables and apply training principles that allow for improvement.

One of these principles that has been studied the most in Exercise Science and that could be said to be the main cause of the organism’s improvement is the “General Adaptation Syndrome” (GAS) or also known as “Specific Adaptation to Imposed Demand”. Both principles, although with different names, come to explain the theory of Hans Selye, a well-known physiologist of Austro-Hungarian origin in which stress is defined as the way that allows a modification of the structures of the organism.

Before starting with the development of this post I would like to emphasize that it is a term difficult to find in scientific literature. In fact, if we enter “Specific Adaptation to Imposed Demand” in the PubMed search engine, we do not find any result that tells us about this principle. However, on the other hand, years later one of the best-known books among exercise professionals was published in which this principle was discussed in the book “Super training” by Verkhoshansky and Siff (1). The principle known as SGA comes to say that the body will change based on the stimuli that we give it.

Let us take a remarkably simple example. If through repetition we make the body understand that it must have a strong heart, lungs and muscles to last 30 minutes running at 4:30 minutes per kilometer, the body will improve its ability to take in oxygen, to process it in the lungs, to send it through blood perfusion to the muscles and to use it in the best possible way by the muscles. On the other hand, if we make the body understand that 4 days a week it must move 100 kg of weight overhead and do an “overhead” squat, the body will improve the recruitment of muscle fibers, will adapt the neuromuscular system so that the nerve signal reaches the motor unit as quickly as possible and recruits the greatest number of fast fibers, and will modify its structures to have more fast twitch fibers available. That is to say, the adaptation of the organism will depend on the stimulus we give it. That said, in today’s post we are going to analyze what is based on the principle of EMS and what are the best tools for the coach to develop a training program according to this principle.

What Does the EMS Depend on?

If we are going to talk about strength training and physical conditioning, we must first be clear that there are two main adaptations to strength training. When we go to the gym and decide to repeatedly overcome a resistance, we are causing two types of adaptations in the body.

Neural Adaptations

We must understand that our muscles work thanks to the nervous stimulus created in the brain, which travels through our spinal cord and our nervous system to our muscles. Let us not forget that strength starts in the brain. This is why people with neural problems or with limitations in the nervous system cannot produce strength correctly (2). If we take this into account when we talk about EMS, one of the first adaptations of strength training will be the adaptation of the entire neural system so that the sending of information is much more efficient.

In fact, it is already known that one of the first adaptations of training is this improvement of the nervous system and… How do we know? It is quite easy. When a person starts training in the gym, we see that the first day he lifts, for example, 10 kg on a biceps machine, but after a month, although his muscle mass has not changed, he manages to lift 20 kg. In other words, the first adaptation that has occurred is that his motor units (those responsible for recruiting fibers) have been activated and have managed to recruit a greater number of muscle fibers. And recently a systematic review with meta-analysis has analyzed specifically in which areas of the brain adaptations to strength training occur (3).

Muscle Adaptations

On the other hand, we all know that strength training together with good nutritional planning makes it possible to increase the body’s muscle mass. In other words, strength training generates an adaptation of the muscle tissue and when the tissue we have is not capable of overcoming an external resistance, the body must create more muscle tissue to overcome it. If for a month, I try to perform ten repetitions of the biceps with 10 kg and I do not succeed, possibly the second month of training I will succeed. The organism will have taken charge of creating more muscle fibers or of thickening the ones I already have so that I can move the resistance about which we have talked.

In this sense, muscular adaptations are given by the number of muscle fibers, by the size of the fibers or by their composition. A part of Sports Science oversees studying the structural modifications that occur in response to different stimuli. For example, a study by Botella and collaborators focused on analyzing the changes that occur in muscle mass in the face of moderate-intensity aerobic training or high-intensity aerobic training (4). In the same way, there are trainings that focus on the increase or improvement of type I fibers, type IIA fibers or type IIX fibers (5).

What Principles Should Be Applied to Generate an EMS?

For a training program to achieve the expected results, there are a series of principles with which it must comply. It is useless to have a great training plan if when I am going to apply it to an individual it does not work for me because of that person’s physical characteristics or social behavior. In other words, I can have the best training in the world, but if I fail to understand the peculiarities of my individual it will never be effective.

In fact, without meaning to, we have already alluded to one of the principles that can never be missing in any planning: Individualization. We will now name the series of principles that are essential for the development of a good strength and conditioning program.


As we have already mentioned, we must consider the person we have in front of us. That is to say, it is not the same to make a strength planning for a 60-year-old person as for a 20-year-old person. It is not the same to prepare for a person who wants to reduce his fat % or for a person who wants to increase his maximum strength. And planning for a triathlete is different from preparing for a woman who gave birth less than a month ago.

Strength training must be tailored to the specificities of everyone, and only in this way will we achieve the first principle of training. In addition, the individualization of our training programs will allow us to segment the service as a trainer. I can know what type of training is more demanded by a 40-year-old man or by a 20-year-old young man.


We have already referred to this principle in the previous section. As we have expressed previously, it is not the same to prepare a triathlete than an administrative woman. First, the objectives are going to be different and so are the sport modalities. While one wants to improve strength endurance, the other wants to improve general physical conditioning and change body composition. This principle tells us that if people have different goals, the training will be different.

Before I go on to the training principles that support EMS, I would like to point out that in recent years the training and fitness industry has shifted dramatically towards all-purpose strength training. So nowadays, whatever your goal (i.e., improve your back pain, win a marathon, reduce fat %, run faster or stay in shape) strength training is recommended.

From my point of view this polarization of training is not at all good for the population. We should not send extremist messages that only value one part of training. It may be good for a 65-year-old woman to work on maximal strength, but it doesn’t have to be the only way to train. If that woman prefers to go for a walk with a friend every day, we should help within that cardiovascular exercise planning and include a strength component such as walking uphill or stopping for 5 minutes during that walk and climbing a bench. Strength training is proving to be more important every day but let’s not be reductionist and forget about other forms of training that are especially useful and fun.


In the world of strength training is known as progressive overload which means that we must gradually increase the training load if we want to continue to improve. Like all adaptations of the organism, when a stimulus that causes an adaptation isn’t generated again, this adaptation stagnates.

So, returning to the example above, if I have been lifting 10 kg for a month and there comes a time when moving them seems easy, if I do not adapt that load and do not progress in it, stagnation is assured. We must continue to stress the body little by little so that it continues to adapt, and we can continue to benefit from improved performance. Does this mean that we must always progress? No, in fact, there may come a time when our body is fully functional and efficient, and it is not necessary to keep progressing in weights or stimuli. There may come a time when maintenance will be sufficient for good health and performance.


To conclude, I would like to make a summary of what the EMS or SAID is and invite all our readers to apply the previously mentioned principles in their planning.

Let’s remember that the SGA or SAID is a way of calling the way in which our organism adapts to the stimuli to which we submit it. That is to say, if we want to improve some physical capacities, we will have to stress the organism in that direction so that little by little it learns. Today we have given examples related to muscular strength, but it can be used for any objective we have. Let’s take as an example the performance of “the pine tree”. The first time we do it we will not be able to hold it because our structures are not adapted for it. Our neuromuscular system has not adapted. If we gradually subject the body to the same stress, the time will come when it has adapted and will allow us to maintain the vertical for a longer time.

The same is true for strength training and neural and muscular adaptations. Remember that if you want your training planning to allow a good SGA you must follow the training principles discussed during this post: individualization, specificity and progression or progressive overload.

Unai Adrián Pérez de Arrilucea Le Floc’h


  1.     Verkhoshansky Y, Siff MC. Superentrenamiento: Paidotribo; 2011.
  2.     Le Vay D. Anatomía y fisiología humana: Editorial Paidotribo; 2008.
  3.     Siddique U, Rahman S, Frazer AK, Pearce AJ, Howatson G, Kidgell DJ. Determining the sites of neural adaptations to resistance training: a systematic review and meta-analysis. Sports Medicine. 2020;50:1107-28.
  4.     Bishop DJ, Botella J, Granata C. Rebuttal from David J. Bishop, Javier Botella and Cesare Granata. The Journal of Physiology. 2019;597(16):4121-2.
  5.     Wilson JM, Loenneke JP, Jo E, Wilson GJ, Zourdos MC, Kim J-S. The effects of endurance, strength, and power training on muscle fiber type shifting. The Journal of Strength & Conditioning Research. 2012;26(6):1724-9.



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Unai Pérez de Arrilucea Le Floc'h
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