Constraints, Variability, Academic Theory, and Player Development in Soccer

Connecting Academic Theory to Training Session Design

I wanted to begin the conversation about coaching and player development at the very foundation, and for me, this starts with connecting of academic theory to practice session design. There are two main academic theories that are used to explain skill acquisition and decision-making, they are the ecological dynamics theory and the cognitive processing theory. I subscribe to the ecological dynamics model because it can be quantified mathematically, and it makes more logical sense to me, especially in a sporting context. My entire soccer methodology is built upon the theory of ecological dynamics, so it is important to grasp the basic concepts of ecological dynamics in order to understand my practice session design.

Basics of Ecological Dynamics

Light reflects off an object, the reflection of light plus the rate of change provides us with real-time information. If a person throws a baseball at your head, the ball will reflect light, as the ball gets closer, the reflection of light from the ball becomes bigger (rate of change). The information from the reflection of light will tell the person the speed and direction of the ball that is propelled towards their head. This formula works when the object is moving and the performer is stationary, when the object is stationary and the performer is moving, and for all the combinations of performer and object movements. The person who had the baseball thrown at their head will automatically couple their physical actions in real-time to the information from the reflection of light. Ultimately, the person will move their head, coupling their physical actions to the current information from the reflection of light and its rate of change. People do not need to be trained to move their heads out of the way of the baseball, this is purely the interaction between the human and the environment. This can all be proven by mathematics using the theory of “Tau” formulated by David Lee. The environment itself is information-rich, it holds all the information the athlete needs if they are attuned to the right areas.

The next part of the theory of ecological dynamics relates to the decision-making process. Ecological dynamics tells us that players are not making decisions based upon the retrieval of past memories, or by saying if A + B then the player executes action C. The game is so fast that players need to change their intentions for action many times in a fraction of a second. When Xavi is dribbling trying to penetrate the defense, his intentions for action are always changing, as invitations for action are opening and closing at ultra-fast speeds. Ecological dynamics views decision-making as a real-time feedback loop between the environment and the athlete.  Information from the environment specifies invitations for action, which are called affordances. These invitations or opportunities for action are athlete-specific and emerge and decay quickly in the game. Let me give you some examples to illustrate the point more clearly. A player who can do a bicycle kick may look at a crossed ball as a chance to perform a bicycle kick. But a player who has never done a bicycle kick will look at the same crossed ball, and not see that opportunity for action, because they don’t have that skill or affordance. This is the difference between player affordances, perceived affordances, and opportunities for action. A slow player will not see the same opportunities for action compared to a faster player when dribbling the ball. Ecological dynamics understands that the environment itself holds all the information needed for players to make decisions in real-time. If we accept that players are constantly perceiving, and in real-time opportunities to perform actions open and close specific to each athlete, then we see decision-making as a very fluid in-the-moment process, it is not something that is based upon memory, calculations, or patterns. Also, players who are perceiving the same affordances opening, we call that a “shared affordance”. If Messi sees space for the striker to run into, and the striker sees the same space, and they both coordinate their physical actions to exploit the defense together, this is called a shared affordance.

The ecological dynamics framework views athletes and sports teams as complex adaptive systems that operate in conjunction with the environment in a circular loop. The sport of soccer is complex, dynamic, and chaotic in its purest form, but it does have limits to its randomness because it is a goal-oriented game with rules. The game is not meant to be separated into pieces and taught in sections. If you are separating the four moments of the game (attacking organization, attacking transition, defensive organization, defensive transition) and training them in isolation, it becomes less game-representative. The information the athletes are perceiving is less real than the actual game, and the coupling of the physical actions to this information is not as useful. The goal is for players to practice in environments that are “game representative”, not separated into individual moments, and allow players to couple physical movements to high-quality game representative information from the environment.

Principles of Play

When you connect academic theory to practice session design it is also important to consider how the practice session connects to the principles of play. If you do an internet search for defensive and attacking principles of play, you will find a variety of principles. Toronto FC in the MLS, established 16 different attacking principles of play. In my opinion, the players do not need to be able to name any of the principles of play. Giovinco, Toronto FC’s best player, spoke limited English, and from day one was their best player. Did Giovinco know the 16 attacking principles of play? Did he retrieve those principles of play from his memory in real-time to make decisions in a split second? Not a chance, he just played. It is very important to understand that words and verbal instruction are often a very poor way to teach the game of soccer. It’s way more important that players can “do it” than explain it. Almost all youth players can tell you that they must spread out in possession, but the reality is they do not do it. The words actually mean nothing because they do not translate into action. This is the difference between knowledge of and knowledge about. Of course, there can be power in words, but you must use words as a trigger, nothing more. I personally don’t think any player will ever benefit from 16 attacking principles of play, it will always be just words. Let me leave you with a few examples; when a coach gives a “high-five” to a player, it conveys a message that is so positive, that it carries energy that no words can describe. The is no way to describe how it feels to contact the ball correctly when using different techniques. This type of feedback between the player and the environment can’t be put into words. When a coach moves a player into a different space on the field, it changes the player’s perception, the new perception can’t be described, it can only be experienced. Hopefully, you can see where I am coming from now.

My thoughts on the principles of play are the following. The principles of play should be very simple ideas that the coach can guide the player’s attention naturally to in a training session. The principles can also be carried out using constraints in training sessions. Let me provide you with examples of both.

Example of the principle of width in attack: The coach notices the attacking team is outnumbered in one area of the field, while there is space to play on the other side of the field. The coach can stop the game for a brief moment, asking where is it less crowded on the field, where is there more superiorities for us, and where might there be a better chance to score from. By questioning the players, the coach is able to focus the attention of the players to another area of the field, making them more attuned to switching the point of attack. The principle of play may have been using width in the attack, but the players didn’t need to know the actual term, what they needed was to view the situation from a new perspective, attending their perception to a new area of the field. The second example would be to use constraints to create width in an attack. Creating two wide channels on the field that the outside backs must occupy in possession, guarantees the attacking team’s shape has width. Using constraints to create width can include making the attacking team play into both channels before they can score, as either the winger or wingback must occupy the wide channel in possession.

When you connect academic theory to practice session design, remember to connect the principles of play by attuning the player’s attention. I prefer using simple principles of play without using a lot of sub-principles. Soccer is a game of manipulating time and space and many of the sub-principles can be explained using that one idea.

Attacking Principles: width, depth, mobility, penetration

Defending Principles: delay, pressure, cover, balance, & compactness

Constraints & Variability

A major part of connecting academic theory to practice session design involves the use of constraint-based training. Essentially a constraint takes away absolute freedom from players, it makes some actions possible, while other actions are not possible, so players must explore alternative solutions to be successful. Constraints change the player’s perception, thus changing the invitations for actions. I use constraints for four different purposes  1) To invite and bring about specific actions you want to see more of from your players. 2) To change perception 3) To amplify errors 4) To create flexible problem solvers who explore many options to succeed. Constraint-based environments can be unpredictable and unstable with lots of complexity. Variability is another word that applies to constraints. If you are always looking to change the environment then that variability is always making the players adapt by searching for new solutions or by adapting or creating a new technical solution. Variability plays a major role in player development. Variability and constraints can also be observed in donor sports like Arena Indoor Soccer or Futsal. These smaller and faster types of environments can shape player development in ways the regular 11v11 game outside can never do.

The actual game itself will present many constraints that will help shape the player’s solutions, but practice session design will be the coach’s main tool to construct environments that promote players finding solutions. Constraint-based training or the Constraints Led Approach (CLA) is one of the main tools for player development that fits into the ideas of ecological dynamics. Constraints are classified as the task (rules, equipment, boundaries), environmental (heat, cold, field, rain, social expectations), and individual (physical characteristics, emotional and motivational).  A constraint-based environment can lead to changes in the perception, movement solutions, intentions, technical skills & tactical solutions. Proponents of an ecological dynamics model look for learning to occur in these unstable environments, and not by doing repetitive rote learning that is not game-representative.

One of the benefits of training in constraint-based environments or diverse unstable environments is the unique skill sets that are developed between the interaction of the environment and the players. Ronaldinho, Met Ozil, Peter Cech, Neymar, Thierry Henry, and so many more have benefited by training in diverse constraint-based soccer environments.  Ronaldinho would often speak about the unique touches on the ball he learned playing beach soccer in Brazil.  He mentioned how those unique touches and skill sets on the ball from beach soccer were seamlessly transferred over to playing 11v11 on the grass field. Other players simply couldn’t understand the types of touches he was taking, because they had never seen them before.  Ronaldinho felt that his beach soccer experience provided him with special skills and an advantage over other players who never played beach soccer. Similarly, Met Ozil credits part of his development to “playing in the cage” at a young age in Germany.  The cage was a small enclosed hard surface surrounded by a tall metal fence that didn’t allow the ball to go out of bounce.  Ozil would play against his older brother and friends, who were all faster, stronger, taller, and older than he was.  The cage and all these environments are great examples of environmental constraints. The cage was the teacher for Ozil, forcing him to come up with solutions to problems at very fast speeds, this is extremely important and relates directly to the 11v11 game. Thierry Henry speaks about playing soccer in parking lots, with shopping carts all over the place. He enjoyed the experience, because there was strategy involved, using the shopping carts as tactical objects in the game. Players could bounce the ball off the carts or use the carts to shield off opponents. The carts made a regular soccer game more complex, making players come up with different solutions, tactics, and decisions. The prolific Brazilian and Barcelona/PSG goal-scorer Neymar, credits his futsal experience in part for his development as a world-class player. Neymar says, “Futsal had a massive influence on me when I was growing up.  It’s a very demanding game and it really helped to develop my technique, speed of thought, and ability to perform moves in tight spaces. I think futsal is a fundamental part of a footballer’s life.  When you’re out there playing, you’re forced to think fast and move faster – if you lose a second, the ball will be gone. It’s a more dynamic game and it’s come in handy at Barcelona. When we play there’s not much space on the pitch so you need to react quickly on the field. There’s no doubt futsal has helped me a lot in my career, it’s one of the biggest passions in my life. I used to love playing it, but unfortunately, I had to stop when I was 13 or 14 in order to grow up as a footballer.”

Ozil, Ronaldinho, Cech, Neymar and Henrys’ development in constrained environments helped them excel in the 11v11 game. I believe these unique training environments have given them a flexible set of affordances and unique perception that other players do not have, this allows them to come up with uncommon solutions. Training in different and unique environments allows the players to perceive the game in a different way. Here is a quote from the great Italian center midfielder Pirlo talking about how he sees the game differently, “I have reached one conclusion, though I think I’ve understood that there is a secret.  I perceive the game in a different way.  It’s a question of viewpoints, of having a wide field of vision and being able to see the bigger picture.  Your classic midfielder looks downfield and sees the forwards.  I’ll focus instead on the space between me and them where I can work the ball through.”  Claudio Reyna,  commented about Pirlo, explaining the differences between Pirlo compared to other players in the MLS, “He’s a player who makes it look easy,” claimed Reyna. “We have Andrea (Pirlo) and Frank (Lampard) in midfield at NYCFC and they are a step ahead.  The best players are two and three steps ahead of the opponent when they receive the ball and that’s what you have to do at the highest level where there’s limited space and the speed of play is much quicker – you have to think ahead.”  Reyna even commented on his own development, crediting a unique playing environment that helped mold him into one of the best players the United States has ever had; “For anyone who remembers those fields, there was dirt, rocks and even glass, it was by far the worst field I ever played on, and I played more games on it than any other field. There was constant soccer there.  Sometimes it was a dust bowl, sometimes it was frozen and the ball was bouncing every which way, as difficult as it was, you had to have your head up to play.  That and playing with older players all the time developed me at a more rapid pace.” Reyna is directly speaking about his development in game-based constraints environments.

It is very important to understand, that verbal directions or instructions from a coach, do not always transfer well when learning soccer movements. Andy Driska Ph. D wrote, “Instructions don’t present a strong enough sensory stimulus to develop an ideal movement pattern. Human movement is largely controlled through perceptual-motor systems that operate somewhat independently from cognitive systems that handle instruction. Giving instructions often puts you into the trap of assuming there is one correct way of performing a skill. In reality, there are a range of acceptable ways to perform a skill.” The message is a powerful one, players need to be put in an environment where they can explore ways to develop unique skills.

Ecological dynamics is dependent on visual search. We need players looking away from the ball in their scanning, but 90 percent of the time players want to focus on where the ball is. 

The above slide is a great example of how important it is to have players immerse themselves in representative constraint-ridden environments for large amounts of time. South London has now become a breeding ground for top soccer players. 14% of all English-born players currently in the EPL grew up playing on the South London small-sided courts. They call these courts the “Proving Grounds”, home to self-organized pick-up games that happen around the clock with no coaches.  The proving grounds are a game-based, small-area, and super competitive environment that translates into unique skill sets technically and tactically to the 11v11 game.

Taking task constraints to another level is the above speed constraint handles, peripheral vision blocking goggles, and headphones. I made the goggles from swim goggles with spray paint to block the peripheral vision, the speed constraint handle can be a piece of PVC pipe, and the headphones you can buy anywhere. These pieces of equipment turn any game into a huge mix of constraints. The glasses force players to have more head movement and more head movement = more completed passes and more completed forward passes. The speed constraint handle takes away a player’s mobility and sprinting speed. The headphones allow no sound, encouraging more head movement and scanning. 

Differential Learning

Another part of my methodology is called “Differential Learning”. Differential learning is about de-stabilizing the existing movement solution by adding additional components that create a de-stabilizing effect. This type of training does not always need to be highly game-representative but I always favor more representative. The individual must self-organize their movements through the destabilizing process, pushing them to find solutions outside of their normal movement patterns. The main objective of DL is to allow an athlete to gain information about the solution space that can be used in future performances. The movement solution is the thing we want to explore, the de-stabilizing factors are the noise. These types of training require a feedback loop between the coach and the athlete. Movement patterns and skilled movement are unique to each individual. There is no linear path to skill and no time scale – all skills are different. CLA and Differential Learning are slightly different but essentially everything is a constraint. However, differential learning can be used to explore the errors to open up new pathways to new solutions.

Below is a quote from Peter Cech talking about the Differential Training Methods he uses with his Goalkeeper Coach.  This is from an article in the “Daily UK” newspaper. 

“This is the way he works.  We try to catch different shape balls, bigger balls or smaller ones because then you need to adapt your hand-eye coordination every time.  Suddenly your brain starts working again.  You can use colors.  Imagine saving the ball but at the same time, a card is held up.  You save the ball and shout the color – you are concentrating on more things.  That makes your peripheral vision better as well.  Your brain is working much more than just with a simple catch.  He is always searching for new things to bring it further, to be more efficient, and try to make things happen for a goalkeeper to progress even at the highest level.  I keep using a table tennis robot that shoots ping pong balls out.  You have to catch it with one hand so it gives you a completely different hand-eye coordination.  Then, when you have both hands facing one football, everything becomes easier.” 

Examples of Differential Learning

  • Use of fields with radically different shapes & dimensions
  • Playing with different size & shaped balls
  • Playing in shirts with arms sewn closed – forces  arms to be tucked inside shirt and distorts balance.
  • Wearing of leg constraints
  • Use of blind folds

The day before a match my team used to play soccer tennis for 30 minutes, now I take that 30 minute block and do DL exercises. Differential learning like anything else can’t be done just one time, it needs to be consistently used over a longer period of time to deliver benefits. I will be adding a DL section to my Youtube Channel very soon.

DiBernardo Soccer Methodology

The foundation of my methodology is built on the Constraints Led Approach, it breaks training into small-area possession and positional game-based exercises, medium-area possession and positional game-based exercises, and large-area possession and positional game-based exercises. The small-area exercises are less positional but still operate in the whole with the coupling of physical actions to game-representative information. The medium-area exercises can become more positional and game model in nature, but can also be self-organizing and unstable. Large-area exercises are more game-model-specific and highly representative. All my practice session environments can be uniquely designed to involve constraints, positional play, and self-organizing possession, and all are connected to principles of play. It is important to understand that possession exercises are not positional. Possession exercises are self-organized by the players, there are no clear positional roles assigned by the coach.

Rondo, Positional Rondos, & Small-Sided Games

I want to be very clear about what “representative game design” is and what types of environments are representative enough to develop players. There is always the debate about rondo training and if it even works for development. First, an old-school 6v2 rondo in a circle is not my definition of a rondo. In my opinion, a 6v2 rondo has value but the value is limited at best. I take the view that rondos can be transitional, positional, have goals, a direction, counter-pressing, and many other things. The rondo can be considered the whole and not the parts for me. The reason is simple, it is about keeping the ball away from fluid defenders in all types of situations that are chaotic and unpredictable. That for me is representative enough, players are coupling physical actions to real information, the same as a real game. Soccer is also about learning to manipulate time and space. Rondos can help develop this skill set. Playing out of tight areas is a transferable skill. Inside a rondo when a defender closes you down, tackles, or cuts off a passing lane, it is a real transferable game-like situation that requires transferable solutions in these small spaces, it is very representative. A 17-person rondo with 3+ players in the middle, played in a larger area, as the outside team transitions into the middle to press and win the ball back when possession is lost, is much different than a 4v2 rondo. The scanning habits of the 3+ players will be high, even the team who just wins the ball must scan a lot when they work their way to their outside positions while being pressed. A 4v2 is a basic fundamental exercise that I would use with younger players to teach backfoot passing & 1/2 turned body position to play forward balls. Rondos don’t need to have touch restrictions, it depends on the exercise design. Rondos do involve principles of play but not in the identical ways of a real game. But the key is that the exercises are representative enough. Variability will help with this. You will never get fully representative in a rondo but that’s ok, it doesn’t have to be. Many people will see my rondos and call them small-sided games, this is just semantics to me. The most important part is that I can connect them to the academic theory which couples physical actions to game-representative information, in a real-time feedback loop.

Isolated Unopposed Technical Training

In my methodology, I limit the use of unopposed training and isolated technical training. The basic reasoning is simple, the players are not coupling physical actions to real information in a chaotic game-representative environment. Team training session time is probably the only time during the week players have the opportunity to make meaningful decisions on and off the ball in game representative trainings. However, I do encourage players to do as much technical training on the their own away from team trainings. Players can’t make meaningful decisions on the ball by themselves, but they can train technique. It is important to understand that technical skill acquisition does not need to be learned from a coach. Skills can be learned through the interaction of the player and the environment. As I mentioned earlier, futsal is considered a donor sport to soccer, it provides an environment that produces unique skills that players would not normally learn on a grass field. Beach soccer, cage soccer, and playing on bumpy dirt fields are examples of constraint based environments that produce unique technical skills in players. These are skills that are not taught by a coach, these are skills brought about by the interaction of the player and the environment. Many other sports have what they call donor sports like arena football, box lacrosse, and floor hockey. All these sports produce unique skill sets in players that they would have not developed by playing the traditional game. One last important point about skill development is that every repetition of a technique is different, every person is different, and flexibility and coordination are all different. A technique performed one way for one person may not work for another person. Players must be allowed to explore movement solutions that fit them. It is possible that a keeper is more comfortable diving to save a high ball using his bottom hand instead of his top hand, if that is what feels right and works for that individual, then it is acceptable.

When coaches are teaching technical skill acquisition they should focus on external cues instead of internal cues to guide technique. An example of internal cues for a push pass would include things like keeping your ankle locked, knee bent, toes up, plant foot pointing in the direction your target, follow through straight, and don’t cross your kicking leg. External cues focus on the outcome or end result of the technique itself,  they are things like, did the ball go to your teammates back foot, did your shot go into the corner, was the pass into space, or did the corner kick go where it was intended.  If you are going to use internal cues, give just one cue and follow that with the external focus. External cues are superior to internal cueing in skill development, the academic theory proves this over and over again. Remember when a technique is being performed, the body is in a constant feedback loop adjusting movement in real time, bringing the movement into a stabilized motion, so a consistent result can be established. 

The above graphic makes the point that every repetition is different. The more repetitions we can get in actual game-based environments the better, because it requires adaption to real information, recognizing the right moment for the action capability. This is much different than dribbling around a stationary cone.

One exception I would like to mention about skill acquisition is about rarely used skills. How many times does a player hit a left-footed volley in a game or training session? The reality is probably hardly ever. Skills like a left-footed volley or bicycle kick might be something you train in isolation.

Academic Theory & Changing Practice Design

We have all seen players dribbling through or around cones that the coach set up in many different patterns. The old-school Wiel Coerver type of team training set-ups look like a musical production in motion, but is this really the best way to develop players? Then you have the coach who prescribes random drills based on what they think the team needs, not subscribing to any methodology. I would question practice session designs that focus on breaking and teaching the game in separate pieces instead of the whole. The academic theory of ecological dynamics clearly points to the reasons why these types of methods are less effective, the below graphics help illustrate the point.

It is important to connect academic theory to practice session design, while further connecting those ideas to the principles of play, and ultimately combining it all into a methodology. A methodology is a way to teach the game of soccer through the age groups in a progressive way. The one thing you will notice about my methodology is that it allows players to make maximum meaningful decisions in game-based, game-representative, and constraint-based environments. The players will love the training because they are playing, and they can all get what they uniquely need from the environment. The sessions do not separate the game into pieces that are unrealistic, giving a small number of players what they might need.