December 30, 2020In Uncategorized14 Minutes

Cheap or Resistant?

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 I became aware of this video thanks to my brother, a professional basketball player, who, showing it to me, expressed his disbelief not so much for the technical performance (for heaven’s sake I think he never achieved 105 consecutive triples even in his best dreams , although he remains an excellent shooter…) but how much for the physical one. He says to me: “But how does he do it, he doesn’t even seem to get tired?” Of course, shooting a basket is not typically recognized as an act of who knows what energy expense, but repeating it more than a hundred times in the space of five minutes, I believe, can very well be considered an activity of a certain intensity. Seeing him repeat this gesture with such naturalness aroused in him the idea that he was (and of course he certainly is) an extremely physically trained athlete. But for my brother, one of the most skilled of the least skilled basketball players (forgive me the joke… perhaps), does shooting 100 times consecutively “cost” as much as Curry?

We normally refer to sporting skills in quantitative terms. That player is good because he makes many baskets, assists, rebounds, etc… or in more “physical” terms because he runs many kilometers, performs many sprints, many changes of direction, etc… We tend to think about quantity, the more trained you are the more things you do. But the quality? Where do we put the efficiency of a movement? How important is it to develop cost-effectiveness in terms of performance optimization?

And so, thanks to my brother’s inspiration, I tried to give a bit of a picture (certainly in a summary and non-exhaustive way) of this concept, which in my opinion is very important, from which to draw many methodological ideas: the economy of movement.



Motor consistency is defined as the ability to achieve the performance goal more and more often through practice. And I think Stephen Curry’s video is a great example of developing motor consistency. In the article “All roads lead to Rome” we discussed the relationship between consistency and variability. The athlete who slavishly repeats the same gesture in the exact same way is often considered good. In reality, international research on motor learning is full of evidence that shows the opposite. High-level athletes are those who are able to vary the shooting method the most (micro-variability) through the use of greater degrees of freedom of movement, while achieving the performance result in an increasingly consistent manner (reducing macro-variability) .

In this article, however, I would like not to talk about the “technical” aspect, i.e. the ways in which this result is achieved, but about the “physical” one. What happens from this point of view to the best players? Is there a relationship between skill level and energy expenditure? Are the most skilled players also the cheapest?
The answer, I can already tell you, is positive and there are many references in international research.
Below I will give you the analysis of one of the articles, in my opinion, more complete and interesting on the subject, namely the Review by the authors W.A. Sparrow and K.M. Newell entitled “Metabolic energy expenditure and the regulation of movement economy” published in 1998 in the international journal “Psychonomic Bulletin & Review”.



The article is truly exhaustive on the topic and I invite you to read it for further information. Below we will focus only on what are defined as the effects of learning on economics, but it is only part of what the authors explain on the topic in question.
In the article the authors demonstrate the concept for which “energy saving” is a fundamental principle that supports the learning and control of motor skills. The human organism spontaneously tends to seek the lowest energy expenditure. In its process of adapting to the environment, it develops, through practice, the ability to reduce energy expenditure while simultaneously managing to improve its competence.

The concept of motor efficiency is defined by the authors as the relationship between the mechanical work developed and the metabolic energy sphex. Consequently, for the same amount of work done, the person who spends less energy is more efficient. And it is precisely this concept that is associated with that of economy, which refers precisely to the quantity of energy spent, coming from food sources and transformed thanks to metabolic processes. One movement is more economical than another when it requires less energy expenditure.



Adaptive movement patterns emerge as a function of the organism’s propensity to conserve metabolic energy, on the one hand, and the demands arising from constraints imposed by the organism, the task and the environment, on the other” ( Sparrow & Newell, 1998).

This beautiful definition by the authors reminds us that sporting ability is nothing more than a behavior that emerges from the interaction of three fundamental factors, such as the organism with its peculiarities, the environment in which the task is developed and the characteristics of the task itself. Motor skill can therefore be defined as the ability to coordinate and control movement to achieve a goal within this interaction.

Why is it said that constraints influence the economy of movement?
If we talk about the constraints imposed by the characteristics of the organism we could say that our “structure” influences energy expenditure. An interesting study by Cavanagh and Karm (1985) demonstrates how athletes of identical body mass but with different characteristics of the lower limbs (more or less thin legs) when running at the same speed, and consequently subjected to the same environmental and task constraints, develop different energy expenses.
If we instead talk about the constraints imposed by the environment, it is immediately easy to think how much meteorological characteristics (an example of environmental constraints) can influence, all other characteristics being equal, energy expenditure.
Task constraints, on the other hand, refer to all those rules imposed by the game, or to characteristics of the game itself such as the use of tools, means of transport or other equipment, which effectively limit performance.

Figure 1 shows a conceptual framework that shows the interaction between the various constraints that we have quickly described and how they influence the economy of movement


An organism’s movements are defined as emerging from the interaction of environmental, task, and organism constraints. The adaptation process is guided by the criterion of minimum energy expenditure, so that the constraints of the task and the environment are satisfied with the minimum metabolic cost” (Sparrow & Newell, 1998).



In the vision of movement as a process of adaptation to the environment and the task, the authors define human learning as one of the main aspects to observe (but not the only one).

Figure 2 highlights what happens through practice in the relationship between energy expenditure and performance. Through training, athletes are able to reduce error, increase movement consistency (see Curry’s transformations in the video, and any other demonstration of sporting skill developed with a high level of achievement) consequently raising the level of performance by decreasing at the same time the energy expenditure necessary to achieve it.

In support of the theory of the economy of movement associated with the level of ability, many studies are conducted, first on animals and then on men, among which I believe that the one by the authors belonging to the Asami group (1976) who examined the relationship between skill level, metabolic expenditure, and ball kicking accuracy.
Figure 3 shows the relationship between energy expenditure, ball kicking velocity, and mechanical efficiency, calculated by dividing the kinetic energy imparted to the ball by the net metabolic energy expenditure. From the two curves shown at the top of the figure it is clear that the metabolic energy spent required to kick the ball was lower for the subjectsmore skilled.
When football accuracy is investigated, an interesting aspect occurs: for both groups, skilled and less skilled players, the greatest accuracy occurs at 80% of the maximum speed recorded, which coincidentally, coincides with the percentage of speed at which the best mechanical efficiency is recorded.


The study by Peter J. Brancazio, published in 1981 in the American Journal of Physics, entitled “Physics of Basketball” in which after a long and complex examination of shooting in basketball, the author concludes that the most skilled players also appear to be those who shoot most frequently using trajectories that require the least force and have the highest probability of success. The ability of the best shooters is therefore highlighted not only in making the greatest number of baskets but also in selecting the most economical trajectories.



One of the main concepts that can be summarized from reading this interesting review is the one identified by the authors as “economy-learning” or “efficiency-learning” principle, a principle for which through practice the organism minimizes energy expenditure to achieve the movement goal.
How is the economy trained? Often among technicians who work to improve performance there is discussion about the importance of physical qualities understood as increasing the abilities of athletes. But how much does knowing how to move on the pitch matter in terms of movement quality? How much does knowing how to do things well have an impact on delaying the onset of fatigue? Within team sports, characterized by strong technical elements that are decisive for performance, I believe that reproducing in training what happens in competition in terms of quality (training following the principle of specificity) can only increase the possibility of impacting the energy cost of movement and consequently indirectly increase the performance potential of an athlete. Training in specificity means respecting the characteristics of the context of the competition, providing, in addition to the purely technical expression of motor skill, also that process of perception-action which forces the athlete to continuously take information from the environment in which he competes, a process itself which requires expenditure of energy for which it is better to develop economy.




December 30, 2020In Uncategorized14 Minutes