Can someone explain this Constraints-Led Approach in acquisition of motor skills?
These are from Keith Davids biography:
“In recent years his efforts have been directed towards establishing a constraints-based framework for motor learning, and the development of a theory of nonlinear pedagogy is a natural consequence of these efforts. Understanding the functional role of variability, and the relationship between variable, random and deterministic components of stochastic processes in human movement systems, remains an important theme for future applied and theoretical work.”
I have read Richard Schmidth’s ‘Motor Learning and Performance’ and I understand his ‘Conceptual Model of Performance’ (which is a base for mine Homoeostasis Performance Model along with Tim Noakes Central Governor), but this Contstraint-Led model was not discussed.
I am interested in hearing more about this if someone is more familiar than I am?
Hi Duxx, constraints led theory in motor learning is based around Nikolai Bernstein and his work on degrees of freedom within motor units. A good intro is the following:
Intermediate motor learning as decreasing active (dynamical) degrees of freedom. Mitra et al, 1998, Human Movement Science, 17.
or
Skill acquisition in sport: Some aplications of an evolving practise ecology. Handford, Davids et a l, 1997, Journal of Sport Sciences, 15.
I’ve got quite a bit of Keith Davids journal articles on the subject as well as some notes putting things together on my other comp and would be happy to share if you like. There is also quite a lot of this in relation to perception action and football (soccer) that I could recommend.
hi all, the following website may be of interest. Search for the reviews by Bizzi in particular. This is an extension of the work by Bernstein. Main topic: adaptation of the motor system to external forces
I was allways interested in Bernstain’s work since reading Mark Latash book (Neurophysiology of human movement, 1998, HK).
The problem of ‘redundancy’ is appliable to greater area than motor control. I tried to explain this in Homoeostasis Performance Model. Motor controler, along with Homoeostasis Controler (or Central Governor, Autonomic Nervous System, you name it), ‘seeks’ to find the optimal strategy to produce movemoent/motion withut causing ‘catastrophic failure’ in organsphysiological systems. Interesting example of ‘redundancy’ in physiology is Pacing Strategy:
‘Possibly the most important factor establishing the pacing strategy is knowledge of the endpoint. The brain teleoanticipatory centre incorporates this knowledge into an algorithm, together with memory of previous events and knowledge of external environmental conditions and internal metabolic function and fuel reserves. This calculation establishes a power output that will allow the athlete to reach the end of the exercise bout at the fastest speed possible without inducing catastrophic failure in any physiological system, which would have occurred if the chosen speed was excessive at any point during the event’. p. 719
St Clair Gibson et al. The Role of Information Processing Between the Brain and Peripheral Physiological Systems in Pacing and Perception of Effort. Sports Med 2006; 36 (8): 705-722
Anyway, I was thinkinh that ‘constraint-led approach’ is about taking away constrains that impair motor learning/skill acquisition. For example, you cannot teach someone sprint start (optimal angles, explosivness) except he allready have enough strength in place. You cannot teach someone to squat if he lack mobility in hips and ankles, etc, etc. Using the ‘indirect approach’ for teaching appropriate sprint starting, CF uses medball throws, hills etc to ‘remove constraints’.
When I read your review at elite-edge, it seems that hills/medball throws create constrains, thus the athlete have less redundancy and he can easily solve the task and thus learn… Very interesting
J Appl Physiol 101: 1506-1513, 2006. First published August 3, 2006; doi:10.1152/japplphysiol.00544.2006
[b]INVITED REVIEW
HIGHLIGHTED TOPIC
Neural Changes Associated with Training [/b]
Changes in muscle coordination with training
Richard G. Carson
School of Psychology, Queen’s University Belfast, Belfast, Northern Ireland, United Kingdom
Three core concepts, activity-dependent coupling, the composition of muscle synergies, and Hebbian adaptation, are discussed with a view to illustrating the nature of the constraints imposed by the organization of the central nervous system on the changes in muscle coordination induced by training. It is argued that training invoked variations in the efficiency with which motor actions can be generated influence the stability of coordination by altering the potential for activity-dependent coupling between the cortical representations of the focal muscles recruited in a movement task and brain circuits that do not contribute directly to the required behavior. The behaviors that can be generated during training are also constrained by the composition of existing intrinsic muscle synergies. In circumstances in which attempts to produce forceful or high velocity movements would otherwise result in the generation of inappropriate actions, training designed to promote the development of control strategies specific to the desired movement outcome may be necessary to compensate for protogenic muscle recruitment patterns. Hebbian adaptation refers to processes whereby, for neurons that release action potentials at the same time, there is an increased probability that synaptic connections will be formed. Neural connectivity induced by the repetition of specific muscle recruitment patterns during training may, however, inhibit the subsequent acquisition of new skills. Consideration is given to the possibility that, in the presence of the appropriate sensory guidance, it is possible to gate Hebbian plasticity and to promote greater subsequent flexibility in the recruitment of the trained muscles in other task contexts.
I was reading a paper on Bernstein and his work that differed in the original translation for the term redundant (in regards to the numbers of DoF), the change suggested was that Bernstein originally used a term that could be translated as abundant. I know it’s fairly pedantic, however, if you look at it from the point of view that the body (controller whatever) has an abundance of options instead of redundant options, I think it makes a difference in your view point on how to deal with constraints.
The other important thing, in my belief, is that with dynamical systems, you are looking at individuals and individual variation and not comparing between individuals.
The issue I may have with the conclusion is that when performing a skill, human beings do not use the same pathways and the same muscles each time we do it. The neural pathway will be similar to, but not exactly the same, the individual fibres and (depending on the movement) particular motor unit may change in performing the skill/movement based on changes with the individual and the environment.
The Henneman size principle (neural recruitment order) has been seen to operate at higher levels as well, so that smaller muscles are recruited before larger muscles (slow twitch to fast twitch) and this is subject to change within the muscle itself, so that different fibres are recruited as needed.
Also, as an out of topic issue, I found very interesting the following ‘stuff’:
central pattern generator and its location and adaptability
Anticipatory postural adjustments
The first is very related to running and anything ‘cyclical’, while the other is related to allmost all movements, but I found its relations to agility (reacton to stimuly and change of direction) non discussed at all? For appropriate fast reaction, good body posture or fast repositioning should take place to facilitate great ground reaction forces in the following actions. Take an example plyo-step before acceleration from parallel stance…
taking it one step further: as far as I can interpret Bernstein, the central thing in motor control is goal directedness, not how you achieve it / which muscles you use. This creates flexibility.
Little children learn by “repetition without repetition”: subtle variations of the same task.
If the output of the “neural network” is to reach goal, than training might be focussed on reaching goals under subtle variations: emotional state, physiological state, physical environment, etc. However, too much variation might not be good, because than you train your neural network for a broad category of goals.
I am not sure whether constraint based learning is (allways) the best way to go. There are reasons to suggest that for example part to whole training does not have a lot of transfer in some circumstances, because the constraints on the part are so large, that the task to be fullfilled changes a lot, and by that the goal the body has to accomplish.
Stefan, you are correct that part to whole learning doesn’t have a very good transfer rate, motor learning (skill-wise) is much like SE, built at the speed you run it at. so this then presents the next part of the equation, the constraints must be dealt with while performing as near as possible the skill being learned. This is where the concept of Functional Equivalence comes in, and thats a whole new topic
I do some teaching and coach, the interest motor control comes from a combined interest in sprinting and psychophysiology.
some of the Bizzi papers above remind me of my presentation many years ago for my bachelor degree regarding the role of the LCN and sleep.
Kelso’s book is good, I had a read a couple of years ago. I tend to stay away from books and stay with Journals as they tend to be a bit more up to date.
Can you expand futher?
Skill is performed/rehearsed in ‘context’, which can be internal (emotional state, fatigue…) and external (situations, opponents…). Thus, the learning of the skill should be ‘contextual’. I don’t think this is possible from the very start, but as soon athlete acquire basic idea of the movement , the reheasal should be ‘put into context’. Also, random and varied practice should be used ASAP.
This lead me toward the misunderstanding of people saying that skill is visual representation, but contrary skill is something that happens ‘beneath’ visual representation. Techniqu is visual representation, while skill is a lot more…
I agree that most of the use our brains put visual information to is ‘beneath’ awareness, however it still plays a very large role in directing movements, both with feed forward mechanisms and feedback. the ‘marriage’ of kinesthetic feedback with visual information places us in the position neccessary for performing skill, the less awareness of this the better.
with athletes of any age or ability, it is always advantageous to place them (via constraints or otherwise) within their own context based on their own ability. for example of this, do you just wait for a sprinter to gain strength etc before working on starts? no, you can work on standing starts and natural movement drills without going near starting blocks.
Duxx, there is allways a context and allways a skill. They go hand in hand. Internal and external state allways have “a value”.
Therefore I question a bit the training of biomotor abilities (strength, flexibility, speed, endurance etc) “in a vacuum”, based on rational thinking (not experience wise!)
the skill in its context has to be learned, why not try to be as specific as possible from day one. What is the transfer rate of training biomotor abilities ‘in vacuum’ to performance ‘in context’?
Can training in context achieve higher efficiency of training / larger improvements than traditional type training (“part to whole approach”)? Just some questions in my mind.
a sidenote:
If a person is motivated, hormone concentrations in the brain change, which makes (Hebbian type) learning more efficiently.
A coach his role can be simply put as keeping motivation up, and avoid motivation drops.
An australian report presented that “good” trainers contributed roughly 20% from going from national level to international level.
Individual motivation contributed also some 20%. Genetics played a big big role.
Being in a succesfull group might be the best thing to choose, to keep motivation up. Mell Siff has noted that the progress in performance over the long run might be closely linked to the level of motivation with which each training session is performed, and maybe not so with what is exactly performed.
Exactly!!! I would go even futher and say that there are NOT motor abilities (as some ‘entites’ in vacuum - motor space) only skills and their transfer. I know you are familiar that Bosh and Klomp also criticized training of motor abilties in their book.
Anyway, what about specificity-overload trade-off?! You cannot be specific and provide large overload? Example squats and sprints!
:rolleyes: