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  • Daniel Kamenetzky


The training process design starts with crafting the performance stories of our players from the data that constantly is collected during games and practices. The strategic data integration and its analysis should uncover the most critical needs of our players.

As I mentioned in my past article, there is a discussion between proponents and detractors of the use of data for soccer. The story only can be told close to reality when data collected is strategically integrated and conceptualized to create new objective information and knowledge. Therefore, both sides are right but incomplete in their perspectives.

To present an example of how to integrate data and create players’/teams’/clubs’ stories, I continue with the analysis of the Club Chivas from Mexico. In this article, we will start to analyze the relationship between body composition variables and the specific work in each field position. We start with the Goalkeeper.

Some of the most important and well-agreed goalkeeper characteristics are:

1) Coordination capacity to be able to perform complex multilateral techniques.

2) Speed, to make those techniques immediately available with perfection under stress in unexpected situations.

3) Strength to jump, sprint, and tolerate intense body contact with other players.

4) Mobility to perform extreme movements with maximum amplitude.

5) Endurance to be able to perform hundreds of technical repetitions a week in training and competition.

6) Attention and focus to constantly track the ball and players to anticipate the game and guide and manage his / her own team (leadership position).

7) Mental relaxation to tolerate stressful situations of aggression and intensity. Receiving a projectile and/or a player at high speed and put the body to stop them, requires imperturbable behavior with high physical capacity.

A biology rule indicates that the organism’s structure design limits what it can do, and what the organism most often does stimulates its structure’s “design”.

In soccer, the design of the training process will determine the physical and intellectual demands that will stimulate and direct the player’s body structure and capacity development. The observation of particular characteristics in top-level players shows the organized and purposely designed process of training (biological and intellectual stimulation!). If correctly crafted and controlled over the 8-10 years of academy process, the result will be similar in most players and in accordance with the specific tasks to be performed at the professional level (field positions).

In the case of the goalkeeper’s body composition, we can see in the pictures below that many characteristics are similar even though they are from different countries and therefore developed under different methodological models. In general, they are very lean, with a minimum stature, and great muscularity. These body variables are critical to performing the specific task of this position at the highest level. A failure to achieve similar characteristics immediately will create limitations in the player’s performance.

With the earlier perspective, we will analyze now the goalkeepers' body composition values published in the article “Anthropometric and Body Composition Profile of Young Professional Soccer Players” published in the Journal of Strength and Conditioning Research in 2020 by Marıa F. Bernal Orozco and collaborators

This example will help the coaching and managerial professionals to understand how integrating few variables will give unique insight when designing the training process and selecting prospects for the first team.


With a simple graph that compares the skinfolds of the three divisions of the Chivas Academy, we can rapidly start creating a profile of the club’s goalkeepers and infer their most probable capacities. As we discussed in the previous three articles, we are comparing each skinfold value with a Canadian general population’s database by age and sex. Remember that the comparison group (black thick line “0” in the graph) includes youth of different physical capacities. We then expect that at the highest competitive soccer level, the skinfolds be at least 2 standard deviations to the negative side (down in our graph), preferable 3 to 4 standard deviations negative. Players with that level of adipose tissue will “look like” the pictures above.

1. We can see that the goalies at each level have most of the skinfolds’ values above the media. This indicates that the professional players have more adipose tissue than the general, non-competitive population.

2. The skinfolds’ value for each anatomic location remains almost constant during the years of professional development. Therefore, we can infer that the training process was not taking into account this important factor even though it clearly was evaluated.

3. We can also infer that since the player was carrying an excess of body weight, most goalkeeper's tasks probably suffered some limitations. For example, we can estimate that the jumping height and speed of movement were lower than other professional keepers of the same experience and competitive level.

4. It is also possible that those players will become fatigued sooner than the competitive level requires, due to the extra effort that the muscle mass has to do for carrying the extra weight. Therefore, many other performance aspects might become compromised: accuracy, attention, decision-making, among other cognitive and physical capacities. Those intellectual and functional variables decrease in efficiency when the physiological fatigue increases (for example high levels of tissue acidosis decrease coordination capacity at the central and local levels).

5. Because of the consequences associated with the Chivas Goalkeepers’ body composition, the risk for injuries increases severely. Flexibility and endurance get compromised. Each action requires a higher metabolic effort. Focus and coordination decrease. Those changes create a “snowball” of physical limitations that affect each other increasing the risk of errors that could lead to physical and/or physiological damage.

The above-mentioned observations might increase in severity when integrating other body composition variables (such as muscle mass), biomechanics analysis (such as jumping and landing techniques), conditional capacity (such as strength), and other performance areas.


What measures the Academy should take during the player’s formative years, to prevent the analyzed inadequate body composition structure and its most probable performance side effects?

1) The coaching staff should consider permanently the information provided by the nutrition department and integrate it with all the other performance variables that should be collected constantly.

2) Generate permanent controls of the variables that are “away” from the “expected” values indicated in the “Academy’s Curriculum” (assuming that there is one!)

3) Design physiological training models according to the player’s body composition and towards the established desired level. In this case, goalkeepers need a higher volume of aerobic work to improve the fat metabolic system (yes! They need to run also!)

4) Control the nutritional behavior and structure of each Academy player. This is critical and enforceable at the professional level. Each player has to eat what the nutrition specialist designs and recommends.

5) Generate an Academy database that congregates every performance variable for each player over the years.

6) Analyze periodically the accumulated data for the curriculum’s redesigning, improvement of the talent selection model, restructure of the training strategies and change of competitive strategies.

The analysis of each soccer player's position can be done as presented. Of course, the more variables collected and the more creative the analytics team is, the more advanced the Academy will become. It's clear now that the talent development process should not be left to the subjective perception of the professionals in charge. It is mandatory to succeed, the utilization of rational resources and strategies.



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