Davids et al. (2003). Newell’s model of interacting constraints adapted to illustrate
the resulting effects on variability of physical performance
One of the most thought-provoking concepts I have dived into through my exploration through skill acquisition research has been Karl Newell's model of constraints, and how that applies to physical performance (Davids et al., 2003). This has been paradigm shifting for me in analysing the effectiveness of the training I prescribe and implement.
Ecological dynamics has been something that I have been exploring extensively of late. Ecological dynamics emphasises the performer-environment (& task) relationship in learning design. This framework is based on James Gibson's insights into ecological psychology and concepts in dynamical systems theory. A number of key principles were highlighted by Chow et al. (2019):
These [principles] include the ideas that the coupling of information and movement needs to be maintained, that practices need to be designed to include affordances or invitation for action, that training environments need to represent the demands of performance and that skill acquisition is brought about by effective manipulations of task constraints which channel learners to successfully interact with affordances.
Newell's Model of Contraints
Diving into the image above of Newell's model of interacting constraints, I will define what each of the constraints refer to. Brymer and Renshaw (2010) provided a good overview of each of the individual, environmental and task constraints within the model.
Individual constraints refer to the unique structural and functional characteristics of learners and include factors related to their physical, psychological, cognitive and emotional make up. Example of individual constraints can include: a player’s body shape and size, fitness characteristics (strength, power, speed etc.), technical abilities (preferred kicking foot) or confidence and motivation.
These person related factors provide affordances (possibilities) for action and dictate action capabilities. They play a significant role in determining the performance style adopted by individuals. These different individual constraints illustrate the distinct strategies that may be used to solve movement problems.
Environmental constraints are multi-layered and are most often presented as physical and sociocultural factors. Physical factors comprise the immediate surroundings and include gravity, altitude, weather conditions, cold, light or pitch surface conditions. Socio-cultural factors include the role of social contexts such as peer groups, and cultural expectations.
Task constraints consist of the goal of the specific task, the arrangement of the activity and the implements or equipment used during the learning experience. In contrast to the other constraints the coach is easily able to manipulate task constraints, for example modifying equipment, deciding on coaching style or setting pitch dimensions.
Perception-Action or Information-Movement is described as a coupling i.e. information regulates action and action regulates information detection or we perceive to act and we act to perceive. This relationship is the basis for skilled performance in sport. As players become more skillful, they develop a stronger link between the information present in the environment and actions. Thus, training this performer-environment relationship is essential for enhanced performance in sport.
How has skill acquisition impacted my coaching?
While this has not caused a massive change in the things I do in my role, it has allowed me to have a deeper impact within my role and I can better articulate my views with coaches and other practitioners.
When viewing traditional or classical strength training, it would be easy to look at Newell's model of constraints and deduce that it is a waste of time. Frans Bosch states:
Historically, sport-specific strength training has mainly been emphasised in sports - bodybuilding, powerlifting, weightlifting - in which transfer plays little or no part - Strength Training and Coordination: An Integrative Approach.
While I accept that this kind of strength training has little to no transfer - because the environment and tasks are completely different - I do not believe that it is time wasted. I believe that it is a way to alter a player's individual constraints to enhance a player's performance potential.
Looking at other examples of individual constraints (overall height, limb length etc.), these are all changeable factors i.e. they will change throughout an athletes career. Height for example is likely to increase throughout a player's career, from child-adolescent-adult. This is an example of an individual constraint that can change independently from the performer-environment relationship described above, but still have a large impact on performance.
Other individual constraints like strength, power, speed are also individual constraints that are changeable, but the difference is that these factors are modifiable through training (bodyweight is also modifiable through training). Since these are modifiable, why not use training to enhance the athlete's physical make-up through tried and tested methods of resistance training, like bodybuilding, powerlifting or weightlifting?
Moving to other example of individual constraints that are typically trained in environments outside of the gym - aerobic fitness, speed & agility for example, this is where I believe a balanced approach works best, but you must define what you are trying to achieve with training.
If I am looking to enhance the "action capabilities" of a player, to increase their potential for increased performance in their sport then I think isolated training can work fine. But this requires a balanced view point - just doing isolated speed training or isolated agility (isolated agility = change of direction training - for future discussion) may lead to decreased times on a specific test, which will enhance the coach's ego, but will not enhance the player's performance on the field. Improving action capabilities is fine, and often necessary, but to improve action capabilities and not work on the player's ability to extract relevant information from their environment and identify affordances is severely limiting the effect coaches can have on their players and athletes. Contextual development, in a representative environment, where perception and action are linked is a vital combination for a training program.
Periodisation of skill acquisition training is not something at the forefront of practitioners' minds when planning training (certainly has not been for me). While there has been some great research around key principles of skill acquisition (some of which have been mentioned in this piece), there has been limited examples of how this may be translated into a performance environment, whether elite or sub-elite. Farrow and Robertson (2016) provided an excellent overview of a potential Skill Acquisition Periodisation (SAP) model that could be used to monitor skill development, with physical training providing a useful reference point.
Ideally, when planning training, both the physical and technical should be taken into account to provide a thorough strategy to enhance performance. To take speed development as an example, training must be planned so that players are in optimal condition to maximise the benefit of speed training (physical component) but it must also take into account the importance of training the skill within an environment that is representative of the sport.
Woods et al., (2020a) provided a thorough insight to how Port Adelaide Power (AFL) used an ecological dynamics framework to guide and promote the integration of performance preparation models that place the athlete-environment relationship at the heart of the learning process. Practical examples were given about the framework they created to develop a playing style the coined "heads-up footy". McKay et al. (2021) also provided similar practical insights into developing attacking principles at the Queensland Reds (Super Rugby).
A personal goal of mine is to bring this SAP model to life within a training environment, and provide a framework to enhance the skill development of athletes longitudinally, rather than simply focusing on the planning of training from a physical perspective only. This is something that I believe and enhance the relationship between performance staff and coaching staff, leading to enhanced athlete preparation, who are better equipped to deal with the chaotic environment they encounter through their sport. Although this may be somewhat contradictory given my last post on microcycle periodisation, I feel this paradigm shift is an indication on my own evolution as a practitioner, and here's hoping there is plenty more to come.
Skill acquisition is one of the most underrated aspects of sports science, and I think it has the potential to be an absolute game changer in athletic development. I am standing on shoulders of some people who are doing some fantastic work in this space, and I'd like to thank the following for spending time in their (virtual) company over the last number of weeks:
The role of athletic development coach requires 4 things, in my view.
The ability to develop the relevant physical qualities - speed, strength, power, energy system development etc. (This point is arguably preceded by the ability to IDENTIFY the relevant physical qualities.)
The ability to develop the relevant qualities in a contextual manner. This may not come directly from the athletic development coach, but the athletic development can have a major impact into the effectiveness of training organisation and planning. A coach does not have to have played the game to contribute here, in fact, I think some of the best ideas can come from people who have not spent time in the sport at which they are working in (I am biased as I have never played my current sport).
The humility to understand it is not about the coach, it is about what's best for the player. Obviously, the more time a player spends in the gym environment will mean that the player gets stronger (provided the coach knows what to do), but is that the best option for the player's performance? Do you need to enhance the potential of the individual, or do you need to transform the potential into performance capability?
The ability to detect errors in performance and coach what it in from of them. This can be done prescriptively (coach decides) or collaboratively (player has more input - representative co-design (Woods et al., 2020b)). Not alone does this require good technical ability, but it also requires humility (again) to admit that the original plan the coach prescribed was not optimal for the player(s) and/or environment.
A good coach must have all four tools in their toolbox to have the most impact.
Brymer, Eric & Renshaw, Ian. (2010). An introduction to the constraints-led approach to learning in outdoor education. Australian Journal of Outdoor Education. 14. 33-41. 10.1007/BF03400903.
Chow, Jia Yi & Shuttleworth, Richard & Davids, Keith & Araujo, Duarte. (2019). Ecological dynamics and transfer from practice to performance in sport. 10.4324/9781351189750-18.
Davids, Keith & Glazier, Paul & Araujo, Duarte & Bartlett, Roger. (2003). Movement systems as dynamical systems: the functional role of variability and its implications for sports medicine. Sports medicine (Auckland, N.Z.). 33. 245-60.
Farrow D, Robertson S. Development of a Skill Acquisition Periodisation Framework for High-Performance Sport. Sports Med. 2017 Jun;47(6):1043-1054. doi: 10.1007/s40279-016-0646-2. PMID: 27873190.
Mckay, Jim & Davids, Keith & Robertson, Samuel & Woods, Carl. (2021). An Ecological Insight Into the Design and Integration of Attacking Principles of Play in Professional Rugby Union: A Case Example. International Sport Coaching Journal. 10.1123/iscj.2020-0065.
Woods et al. Sports Medicine - Open (2020) 6:36 https://doi.org/10.1186/s40798-020-00268-5 (a)
Woods, Carl & Rothwell, Martyn & Rudd, James & Robertson, Samuel & Davids, Keith. (2020). Representative co-design: Utilising a source of experiential knowledge for athlete development and performance preparation. Psychology of Sport and Exercise. 10.1016/j.psychsport.2020.101804. (b)