Everyone marvels at the most dexterous (Bernstein, 1996) display of movement in sports, and rightfully so! Have you ever asked yourself, “how do athletes coordinate and control their movements to seemingly find functional fits to the problems they face in sports? Or simply, how did they do that!? If you’re a coach, you might be asking yourself, how can I help?

The constraints-led approach (CLA) has its origins in the original constraints model proposed by (Newell, 1986), where he emphasized that movement is an emergent property of three interacting constraints, classified into the organism, environment, and task categories. Applied to sports, Davids et al. (2008) suggested that task constraints are reflective of things like rules, equipment, boundaries, opponents, and teammates; environmental constraints reflect things like light, humidity, temperature, and social expectations; and individual constraints reflect things like height, body weight, motivation and fatigue levels. It is important to note that the CLA is a specific methodology underpinned by ecological dynamics and nonlinear pedagogy where constraints are purposely manipulated with a specific goal in mind (Gray, 2020; Yearby et al., 2022). Therefore, constraint manipulation in practice can be very powerful when used to help athletes search for and discover ways to coordinate and control their movements in context, leading to them solving more problems that emerge during gameplay. 

Using the CLA, basketball coaches can support their players by creating situations in practices that promote self-organization (for more on self-organization, see https://emergentmvmt.com/self-organization-movement-meet-up-call-june-15th-2021/). In basketball, self-organization is the process of a player coordinating their body to perform basketball-specific sequences, such as passing the ball or finishing at the rim. Self-organization is shaped by the confluence of these aforementioned constraints, and because these constraints are ever-changing, no basketball possession is ever the same. This contrasts to the traditional approach whereby organization supposedly occurs from within a hypothesized internal structure (Araújo et al., 2009).

Furthermore, using the CLA in practice provides athletes with the opportunity to search for movement solutions similar to those that will emerge in competition. This differs from traditional approaches where coaches believe there is one “correct” movement pattern players should supposedly perform skills. This is characterized by a belief in “fundamentals” and specific techniques, which are drilled into players about how they should pass, shoot, and play defense. These movements are explicitly taught by coaches to their players in practice activities such as 1-on-0, 2-on-0, and pattern rehearsal 5-on-0.

In these traditional practice activities, it’s very common to find little to no specifying information for the players to interact with to organize a functional movement solution. This is essentially the information in the game that will shape a players’ actions, such as the changing interpersonal distances between teammates and opponents, spacing templates, location of the ball etc. By training in a 1-on-0 setting, a player has no defender and no teammates, removing many of the opportunities for action that naturally present themselves within competition. Under an ecological dynamics framework, these opportunities for action are referred to as affordances (Gibson, 1979). The information perceived by an athlete during the game specifies affordances (Yearby et al., 2022). It is important to note that affordances are continuously changing during the course of a possession. Affordances may invite different behaviors for different athletes, depending on their ability to attend to specifying information and act upon it.

In traditional environments, players are held back with their development as they are required to master very specific techniques before progressing to more complex situations with defenders. This holds players back from experiencing a number of different situations and acting upon various affordances, which is required in games in order to be successful. 

During competition, a continuous process of perception-action coupling occurs. Players must perceive information in their environment, such as the location and positioning of teammates and defenders, the time and score, and so forth, which shapes the self-organization process. In 1979, in his seminal text, J.J. Gibson stated, “We must perceive in order to move, but we must also move in order to perceive” (p. 223).  The traditional approach focuses overtly on the action component, training ‘techniques’ and then assuming that players can then somehow ‘plug in’ these movement sequences at the right time in games. This does not allow players to become sensitive to information in their environment and acting upon real affordances, which is what is required of players in the actual game. Essentially, coaches make all the decisions for their players through this approach by promoting pre-determined movement sequences. This is observable in many current NBA pre-draft workouts whereby players replicate techniques with minimal variation from repetition to repetition, despite it being physically impossible to repeat the same movement solutions in games because the constraints are ever-changing. 

Let’s revisit the original constraints model proposed by Newell to take a deeper look at the different categories of constraints in a basketball-specific domain, and how these shape the movement solutions observed when watching players in-game. This helps us to understand why every movement solution – whether passing, finishing, shooting or playing defense – is so unique:

Understanding the Role of Constraints:

Individual Constraints

Let’s start by using the examples of four NBA players: LeBron James, Nikola Jokic, Kyrie Irving and Ricky Rubio. Individual constraints refer to the characteristics of each player, such as their height, wingspan, weight, vertical ability, emotions, fatigue, etc. Some of these characteristics change over long timescales, whereas some (such as fatigue) can change relatively quickly. 

LeBron James dominates the court with his unique combination of size and athleticism. His individual constraints are very different to a player like Ricky Rubio. This enables LeBron to coordinate his body using movement solutions that simply aren’t possible for other players, due to the fact that LeBron has significantly different action capabilities. How do individual constraints relate to the ability to act upon affordances in-games? 

Firstly, Rubio’s individual constraints (e.g., height, weight, and wingspan) contrast greatly with LeBron’s, and this is why the solutions used by both players vary. If handling the ball in a Pick and Roll, LeBron will use different solutions compared to a player like Rubio. For instance, with LeBron’s athleticism and size advantage, he may be able to act upon particular affordances such as attacking an up-to-touch drop defender with a quick burst of speed. Meanwhile, Rubio is renowned for his court vision and ability to perceive defensive coverages as well as any defenders pulled out of position in a pick and roll. Rubio’s ability to attend to this information is what sets him apart, as well as how he exploits such occasions through using a variety of functional passes. Other players, particularly if they have been immersed in an environment with traditional coaching practices, may not be as attuned to this information. 

While the task constraints in a pick and roll are constantly changing, such as the spacing, defensive coverages, etc., so are the personnel involved (the ball handler, ball handler’s defender, picker, picker’s defender). With every player having unique individual constraints, this shapes the different functional solutions on display and explains why no pick and roll possession is the same. For instance, if Rubio observes a defender over-helping or getting ready to tag the roller on the weak side, and he makes a skip pass over a bigger defender switching onto him, it is likely the pass and way in which he passes will be different compared to when doing this against a smaller defender. This unique interaction between the individual and their environment shapes the skillful behaviors on-display, and the omission of such interactions in on-air drills is one of the reasons why the traditional style is most limiting. 

Another example highlighting the role of individual constraints could be a signature LeBron James play where he secures a defensive rebound, bust-out dribbles to start the break, and finishes the play with a highlight dunk. LeBron’s height, strength and vertical ability allow LeBron to be in a more optimal rebounding position compared to a player like Rubio. In Rubio’s case, the rebound is more likely to fall to one of his taller teammates due to their more advantageous individual constraints within the context of rebounding. Therefore the affordance (i.e., opportunity for action) for Rubio to rebound and bust-out dribble with momentum up the floor are much less inviting. As LeBron dribbles up the floor, he is constantly surveying the floor and acting or not acting upon affordances: for instance, using his size to quickly scan the floor and spot a gap in the defense, seeing the chance to get behind the defense by using a burst of speed. Rubio, particularly coming off two ACL surgeries, does not possess this same explosiveness and so he may not be able to act upon the same affordance, let alone finish the play with an above the rim dunk. 

It is worth highlighting that these individual constraints could be changed through an effective athletic development program, as the right program can expand a player’s potential for moving in different ways. Ricky’s aforementioned previous ACL injuries may affect how his movement solutions emerge. He will have to adapt his movement behaviors as a result of the injury. Psychologically this could lead to Ricky rejecting particular affordances such as jumping through a window in-between defenders to finish, in order to avoid another injury.

Task Constraints 

Additionally, Ricky is confined by the expectations and role of his position as a point guard. He is less likely to find himself close to the basket to be in a rebounding position in the first place. This is an example of a task constraint, which include all the rules of basketball itself (e.g., shot and game clock, boundary lines, violations, aim of the game, etc) as well as factors such as coach feedback, impact of a game model or scouting plan, time-out instruction, etc. Within practices, task constraints extend to the aim of an activity or small-sided game (SSG), which could also include the scoring system used, the playing-size used (e.g. half-court, full-court, quarter-court) and the number of offensive and defensive players within the small-sided game (e.g. 3-on-3, 4-on-3, 1-on-1 etc).   

Through the proper manipulation of task constraints, coaches can design SSGs in practice that expose their players to the same affordances encountered in games. This will allow players to not only be able to act on these opportunities in-games, but also be prepared when they arise as they are able to come up with different solutions to solve the task at hand. For instance using the possessions explained above, a 1-on-2+1 activity could be created for LeBron to work on the rebound, potential bust-out dribble and finish at the rim. Critically, this situation may change each time through defense being placed in different locations, leading to different affordances. Likewise, the Pick and Roll possession could be replicated through a 3-on-3, with the defensive coverages and situations slightly changing from repetition to repetition.

The complexity of these possessions are impossible to replicate doing on-air player development. For the teams who have used this traditional approach in their player development and team practices, players have only improved at these scenarios through the game experience they have accumulated. Therefore, the advantage teams can receive from practicing in this way is notable as players will be exposed far more to the situations that are actually occurring in-games. With the right task constraints, player development becomes purposeful as teams are not solely relying on games as the only opportunity for players to be exposed to real basketball situations. Simply put, if a player has more situations in practice finishing with live 1-on-1 defenders as opposed to 1-on-0, this is going to help them significantly when it comes to playing the game. The importance of manipulating task constraints within SSG’s is critical, and the reason for the second part of this blog focussing specifically on how coaches can use the CLA with their players.

Environmental Constraints

These consist of physical variables such as lighting, temperature and altitude of the playing location, but also social factors such as cultural and societal norms, beliefs, family environment, friendship groups, and more. While individual and task constraints are the most important practical considerations for coaches to think about in terms of how they plan and deliver their practices, understanding the impact of environmental constraints helps provide an insight into how these different categories of constraints are continuously interacting and shaping the performances we see in front of us during the course of a basketball game. 

For instance, Nikola Jokic plays in the high altitudes of Denver, Colorado while Kyrie Irving is in downtown Brooklyn, New York. Therefore regularly living and playing in Colorado has allowed Nikola to adapt to playing with lower oxygen levels. Furthermore Nikola grew up in a country (Serbia) where basketball is extremely popular and a national sport, which no doubt had an impact in shaping his development compared to growing up in a country where other sports are more dominant. Additionally, Kyrie Irving may prefer living in the centre of Manhattan with his close friends, making the most of what New York has to offer. On the other hand, picture Nikola living with his family in Colorado, close to the Nuggets’ practice facility in a quiet suburban neighbourhood outside the city centre. The quiet area enables him to have great sleep every night, while his family life is smooth and comes without distractions. He has an organized personal assistant who takes care of everything from nutrition, to laundry, to public relations. On the other hand, living with friends means Kyrie frequently likes enjoying the New York nightlife. With the notorious NYC traffic, it makes it hard to get to the practice gym to work with player development staff. Meanwhile for Nikola, the commute to the gym is a 10 minute walk.

By understanding the impact all categories of constraints can have on a player, we understand that player development goes so much deeper than solely being on-court and adopting the traditional approach of reproducing the performance of specific techniques over and over again. 

Using the CLA: Basketball Examples 

What does using the CLA look like in the context of a basketball practice? Using well-designed small-sided games (SSGs), such as 1-on-1, 1-on-2, 2-on-2, 3-on-2, 3-on-3 etc., facilitates the emergence of functional perception-action couplings in learners (Davids et al., 2013). While using SSGs, task constraints are manipulated in a purposeful way, while the impact of individual constraints are also considered within the practice design as evidenced by players frequently changing pairings, teams and match-ups.

Using such SSGs helps create representative learning environments within the practice where players interact with affordances (i.e., opportunities for action) that are similar to the affordances they will encounter in an actual 5-on-5 game. Within player development, these affordances naturally appear in SSGs that have well-designed task constraints. This contrasts to a work-out whereby a player takes part in lots of 1-on-0 practice, where perception-action coupling is completely removed. Such activities create artificial practice environments as they are completely different to what a player actually experiences within the game. 

The key thing to consider is how task constraints are manipulated purposefully; see the link below for an example. Constraints certainly can eliminate potential outcomes from occurring, so coaches have to be very careful to refrain from over-constraining players by too heavily restricting the movement solutions players can use. For instance, a common approach that has been emerging recently in the basketball world is coaches constraining to constrain. This means they elicit one specific movement behavior, for instance, a live 1-on-1, whereby SSGs become too heavily constrained and players are instructed to employ only one movement solution, e.g., only shooting a floater or a contested jump–shot. Too much time in these scenarios may lead to players only relying on one solution.

Another commonly seen occurrence is coaches teaching explicit techniques to players, then designing SSGs which are over-constrained, where the players are encouraged to use the same techniques that were just explicitly taught. However, this is not what the proper usage of a CLA is about and can strip their authenticity. Instead, using the CLA ecologically means that coaches should purposefully manipulate task constraints to invite potential movement solutions to emerge. 

What questions do you have surrounding practical applications of the CLA within your practices, and are there any other key questions you would like us to clear up? Send in your questions via Twitter or reply in the post below, and we will do our best to answer them in the next edition of this blog. 

Alex Sarama and the team at Emergence 


  1. Araújo, D., & Davids, K. (2009). Ecological approaches to cognition and action in sport and exercise: Ask not only what you do, but where you do it. International Journal of Sport Psychology, 40(1), 5–37.
  2. Bernstein, N. (1996). On dexterity and its development. In Latash, M.L. and Turvey, M.T. (Eds.), Dexterity and Its Development. Lawrence Erlbaum Associates.
  3. Davids K, Button C, Bennett S, editors (2008). Dynamics of skill acquisition: a constraints-led approach. 1st ed. USA: Human kinetics.
  4. Gibson, J. J. (1979). The ecological approach to visual perception. Boston, MA: Houghton Mifflin.
  5. Gray, R. (2020). Comparing the constraints led approach, differential learning and prescriptive instruction for training opposite-field hitting in baseball. Psychology of Sport and Exercise, 51, Article 101797. 
  6. Tyler Yearby, Shawn Myszka, William M Roberts, Carl T. Woods & Keith Davids (2022) Applying an ecological approach to practice design in American football: some case examples on best practice, Sports Coaching Review, DOI: 10.1080/21640629.2022.2057698

Alex shares team and player development ideas for coaches, teams, federations, and organizations all around the world. Alex’s focus is on helping coaches stimulate their thinking by combining their personal and practical experiences with the empirical evidence which exists within the sports research world. Many of these evidence-informed coaching ideas that Alex shares are based upon the Constraint Led Approach (CLA). Alex specialises in helping coaches make sense of the research, putting this into basketball-specific examples so that coaches can immediately integrate these ideas into their practices.

During the season, Alex is the Head Coach of College Prep in Borgomanero, Italy. College Prep is one of the few programs existing in Europe which aims to send players onto careers in the NCAA or professional opportunities within Europe. The first year commenced in the 2021/22 season, with fifteen players from ten different countries around the world. The aim of the College program is to share Alex’s work with the wider basketball community, showing the benefits of implementing the CLA as opposed to relying on traditional, hand-me-down coaching practices that still dominate the coaching community.

Alex’s work has been adopted by coaches all over the world and he has delivered coaching clinics and camps in over 35 countries. This has included delivering clinics and coach education events for NBA and NCAA teams as well as numerous other organizations including the German, Swedish and Czech Basketball Federations, NBA Europe, NBA India, as well as many more. In 2021, through Basketball Immersion he released the BDT Offense, the world’s first resource to help coaches develop their own conceptual offense from scratch, using modern coaching ideas.

Alex’s coaching journey began as a 14 year-old in his hometown of Guildford, England. Alex started coaching the Under 12 team at his school, before then going on to start his own club aged 16. Over the next few years, the “Guildford Goldhawks” became one of the most established youth clubs in the South of England, producing over 10 National Team junior players, in addition to running major international events featuring coaches and players from all over Europe. Alex ran Goldhawks semi-remotely while studying History at the University of Nottingham.

After graduating in the summer of 2016, Alex was immediately hired by NBA Europe. Alex relocated to Madrid, where he delivered both player and coaching clinics throughout the EMEA region.  Alex worked with a number of major stakeholders including Federations, Charitable Foundations and NBA players themselves to grow the game. Sarama worked on the Jr. NBA and Basketball without Borders programs, in addition to coaching at numerous NBA Player Camps.

In August 2019, Alex left the NBA to properly pursue his coaching dreams. As Technical Director of Elite Academy in Belgium, Alex wrote curriculums, developed the coaching staff, reviewed practice plans, led internal clinics and travelled internationally to deliver camps and coaching clinics. In June 2020 Alex’s new chapter started with Basketball immersion, teaming up with Chris Oliver to realize the vision of sharing the game and helping coaches and players benefit from evidence-informed ideas.