Greg Dea: Motor Control – Complex to Simple
Let me ask you a question:
Can you spot competent control of motion, i.e. motor control, in your clients?
If yes, could you answer why you called it competent and could you be objective about it?
If no, why not yet?
It seems your own professional bodies are saying we’re experts in it. So why has it been so hard to answer such a simple question?
Let me jump straight to answering the questions I asked you.
Movements done competently look clean and easy. Movements with incompetent motor control look the opposite – dirty and difficult. In countries where English is not the primary language, “dirty” is misinterpreted, so here’s an updated concept:
Competent motor control looks smooth and easy, versus jerky and difficult.
Nearly 90 years of thinking and research into motor control can be difficult to coalesce into clinical guidelines. Yet, there you have it – four words will help you categorize motor control to reliably improve your diagnosis and choice of treatment.
Smooth & Easy = competent motor control.
Jerky & Difficult = incompetent motor control.
That’s the iceberg statement. Smooth and easy = competent motor control. Jerky and difficult = incompetent motor control . . . for a specific pattern in a specific position.
Let’s dive below the surface.
First, I’ll reiterate a definition of motor control.
Second, I’ll explain where the competent/incompetent criteria come from.
Third, I’ll talk about why it’s important to be objective about calling it, and where objectivity derives from.
Movement variability exists and should be acknowledged, but we should have a cut-point at which time we say, “that movement is unacceptable.”
Don’t gloss over that statement.
Let’s compare it to sport, say, golf. A drive off the tee is variable for every golfer, yet the cut-point for when we say, “that drive is unacceptable” is when the drive goes outside the fairway. There’s a band within which a drive is acceptable – it’s the width of the fairway.
That’s called a performance bandwidth. Movement is like that. Variation exists. We should recognize when variation outside a bandwidth has occurred – it matters for performance success, efficiency and safety.
Earlier I said our professional bodies are saying we are experts in motor control.
The American Physical Therapy Association (APTA) Vision Statement, adopted in 2013, includes the statement, “Transforming society by optimizing movement to improve the human experience.”
The Australian Physiotherapy Association (APA) Vision Statement, adopted in 2012, includes the statement, “With scientific foundations, physiotherapists are experts in exercise and movement.”
The Sports Osteopathy Australia Quality Practice Framework proposed in 2017 includes the statement, “Knowledge of fundamental movements, biomechanical requirements and ranges of movement required in general for risk minimisation in sport and athletic activities.”
With all that expertise including the word “movement,” we have to remind ourselves what it really means.
Movement requires mobility and the control of it.
Motor control is the control of mobility. It relies on feedback from mechanoreceptors within body parts that have available range of motion. Thus, it relies on adequate mobility. The mechanoreceptors detect changes in strain, stress and shear. They need to have adequate range of motion available to detect changes in range of motion. The detection of such change travels from the periphery, as an afferent signal. The signal is processed, meaning it modulates any cortically-driven, planned movements. This is seen as a reflex efferent response to appropriate muscles to stabilise a joint against movement in all planes (static stability) or permit movement in a primary plane while controlling against movement in other planes (dynamic stability).
Can we call motor control competent?
We can call motor control competent in two main ways. The complex way is unreliably unrecognizable clinically, yet it makes up the dominant practice of clinicians. The simple way is emerging among expert clinicians and coaches – it just hasn’t been articulated well enough to be teachable, yet. These are the three criteria against which motor control is judged:
The complex way is this:
- Muscles activate in an order that’s related to general movement patterns,
- Muscles activate in those general movement patterns in a timing that is mostly invariable,
- Muscles activate in a force distribution relative to each other that is also mostly invariable.
This is what motor control research tells us repeatedly. [1, 2]
There’s every chance you will have received instruction on palpating segmental stabilizers and prime movers and been instructed that you should feel activation in one of these before another. There’s a good chance you were also instructed that the segmental stabilizers should activate at a low level relative to the prime movers. These instructions were based on research that flows from topics such as proprioceptive neuromuscular facilitation of patterns (PNF), to neurological rehabilitation, to back pain and neck pain, athletic injury rehabilitation and probably had some influence from bodybuilding. These instructions became reasons for clinical instruction to activate specific muscles. That led to clinicians reducing their clinical evaluation to palpating and cueing individual muscles.
Now, here’s the reasons the above approach is not objective.
- It’s not possible to detect these criteria if you look for them as they are. Palpation of sequencing, timing and force distribution is unreliable.
- Cueing of explicit parts activation increases EMG activity but doesn’t transfer to learning of movement patterns. This evaluation approach is like testing each function of a car when it’s parked in the garage. This cueing approach is like trying to put four steering wheels on a car, or multiple gauges on the dashboard and expecting the driver to be able to negotiate a corner, or even a straight line, smoothly while paying attention to each steering wheel or each gauge.
The criteria above are not in question. They are based on general movement patterns (GMPs), that have:
- invariable sequencing,
- invariable timing, and
- invariable relative force distribution.
It’s not the criteria that’s the problem – that’s science revealing something about how we move.
Further, the motor control research tells us that control of movement is:
- specific to each context,
- driven by reflexes, and
- originated in the central nervous system and modulated there too.
That’s a lot of profound terms to process when you watch someone move. Confusing, right?
Normally, this confusion is coalesced into a single recommendation to look at the “quality” of movement. Further, we are often told that to refine our ability to assess or screen movement, we need time in the game, observing our clients. Many have said that a competent coach doesn’t need formal evaluation – he or she only needs to observe their athlete in training with a keen eye. This approach tends towards “an evasion of evaluation and dilution of expertise” – not an enhancement of expertise. When expertise is diluted, a client’s movement competency falls below the cut-point without us seeing it.
Our industry needs simplified teaching points for a complex problem. That’s our responsibility.
I call the evasion of evaluation a problem because only with accurate, filtered evaluation can we reveal barriers to performance.
Read that again. I call the evasion of evaluation a problem because only with accurate, filtered evaluation can we reveal barriers to performance.
Evaluation preserves expertise, maintaining reliability, validity and the ability to move the needle of change. It is thus our responsibility to use expertise to simplify the complex without ignoring the important revelations. The skill of education has diluted to instruction, telling us to look at the coordination (sequencing), timing and percentage of maximal voluntary contractions (MVC) when assessing motor control. You’ll recall this from when you were taught to palpate transversus abdominus, or multifidus or gluteus medius, in relation to prime movers above it and below it. Or you were taught to palpate, or cue, vastus medialis obliquus (VMO) to activate before other members of the quadriceps.
It has been further stated that by providing a comprehensive training program, testing of movement competency isn’t required. Therein lies the rub – how does one pass on the skills of competent observation to emerging coaches without a keen eye? Keenness without criteria is rudderless journeying. The answer, of course, is training to observe as much objectivity as possible, with criteria. The refinement of such criteria comes then with the different populations, tasks and safety ranges for each performance bandwidth – that definitely takes some time in the game to understand.
We return to our original problem: To take the complex and make it simple.
While the above criteria can NOT be detected clinically, we can still observe a movement and call it competent because we can observe when the opposite occurs – variable sequencing, variable timing and variable relative force distribution. A movement will look jerky, not smooth, and the individual will use excessive effort for a task that has muscle coordination out of sequence, or out of timing, or with inappropriate force distribution between synergists.
In simple terms, when we see altered motor control, it looks jerky and difficult.
As for the question of objectivity, we are led by what is known as performance bandwidths. The goal of keeping movement within a performance bandwidth is three-fold:
- to increase the chance of success,
- to be safe, and
- to improve efficiency of movement
These criteria allow us to look for mistakes that are outside of the “acceptable.” A movement that has a mistake deemed undesirable or unacceptable is one that:
- Lessens the chance of success,
- Increases the risk of injury, and/or
- Reduces the efficiency of the movement.
What we deem acceptable is based on three elements:
- Performance parameters of a population,
- Safety ranges, and
- Task specificity.
When a movement exceeds a tolerance for being correct, it is deemed to be outside the bandwidth and should be corrected. There are many examples of performance bandwidths being applied already. Remember the drive off the tee that goes into the rough? Outside acceptable. Or the basketball player who dribbles outside the court? Outside the bandwidth deemed acceptable. Or the player who misses the shot. These are all performance bandwidths. We have the same for movement, and it matters for efficiency, safety and success.
In the specific sports environment, such as football (soccer), if a short pass does not get to the feet of the teammate, it lessens the chance of success for evading interception, passing on before being tackled, or shooting before the keeper can adjust to the new origin of ball movement. The pass does not have to be specific to the bootlace area, it just needs to be within a small area at the feet. By providing a bandwidth with tolerance, retention of learning is improved. This means the athlete who plays football, made aware of the importance of a pass to the feet, can improve learning, if they are not failed because of imperfections.
In volleyball, the hit that lands out of the court loses the point for the hitter. A hit that is directed very broadly within the court is successful, unless the opposition is of a high enough caliber to receive and return the ball. In that case, a coach trains a hitter to look for smaller areas of court to hit into – those areas harder to return the ball. So, at lower levels of sporting success, a wide but defined bandwidth keeps a team or athlete “in the game.” A narrower bandwidth is only required for higher levels of success.
In golf, a broad bandwidth exists by simply hitting the ball forward. A narrower bandwidth exists by hitting the ball forward onto the fairway or green. An even narrower bandwidth exists by hitting to a specific part of the fairway or green. Hitting closer to a specific spot is not usually required – to aspire to landing areas that are very narrow is to lessen the chance of success, much in the way of hitting off the fairway. There is a bandwidth that is neither too wide nor too narrow that encourages success. The golfer learns by knowing the result and refining their movement performance to achieve within a bandwidth.
Even basketball has a performance bandwidth – it’s just a much narrower one – the net is just big enough to accommodate the ball. A slight deviation from the backboard angle will see the shot be unsuccessful.
In the motor control learning setting, the performance bandwidth also exists. Any movement that lessens the chance of success is outside the bandwidth. The performance bandwidth exists to capture those movements that are inefficient. Inefficiency leads to fatigue, a pre-load for capacity.
Read that again. Inefficiency leads to fatigue, a pre-load for capacity.
“With a 3 in the inline lunge or deep squat (on the Functional Movement Screen), the intrinsic criteria that earned you a 3 offers you a buffer zone if you need it, in the presence of fatigue or travel. The criteria are no pain, minimum levels of mobility and motor control. Having these criteria is not a guarantee of insurance, but it’s more than a 1 or 2 has. Many times, in sports you’re called upon to adapt or micro-adapt to certain weather conditions, surfaces or other issues – extrinsic factors. The more scores of 3 you have, the more room you have for sensory input. You have a higher range of a sensory gauge – if your speedometer only goes up so far, then everything after that is a red line to your CNS. If your speedometer is stretched out before you red line, you get better sensory information.
So, you can look at scores of 3 in two ways – a biomechanical buffer zone or insurance policy, but it’s also a neurophysiological openness. Having scores of 0 or 1 in the FMS means you’re pre-loaded with altered motor control due to pain, or pre-loaded for movement. This is where dysfunctional compensation may likely occur as well, increasing the risk of injury. Being pre-loaded for movement means you must use more resources than others, making it more difficult to still be present at the end of a period of time. The presence of a buffer zone and neurological openness supports completing more of the planned training program, an important factor in success in performance training.” 
Movement bandwidths have been seen in elite sport. Movement ability, known to be associated with the likelihood of future injury, is also related to the ability to improve longitudinal competitive performance outcomes in elite track and field athletes in the USA.  Elite USA track and field athletes with higher composite scores (14 or above), no asymmetries, and individual scores of 3 on the deep squat test had significantly better performances 12 months after evaluation compared to those with low composite scores (13 or less), asymmetries and deep squat scores of 1.
Some years back, I worked with a coach who told me that movement evaluation wouldn’t be undertaken formally with emerging junior athletes because no one could be taught to do it as well as I knew it. There’s two elements worth discussing there. First, the individual is wrong – movement evaluation can, and is, indeed, taught extremely well, in a simple framework that organizes and filters complex information – in the Functional Movement Screen and Selective Functional Movement Assessment courses. Secondly, if a learned coach has already decided that evaluation of movement is too difficult to teach and learn, without exploring movement evaluation, there’s a problem with a perceived complexity. That’s our problem and we should aim to simplify the message without dumbing down the complexity behind it.
Motor control is rarely discussed in professional circles, yet when it is dysfunctional it is in the top three risk factors for future injury and could be a limiting factor in performance. The other two of the top three risk factors being previous injury and significant acute changes in training load.
Of those top three risk factors, only two are modifiable – training load and motor control. Further, motor control could be the limiting factor to the person’s responsiveness to training load.
Let’s get some perspective on the true importance of motor control. The importance of motor control lies not only in its role as a cause, contributor or complicating factor in risk of future injury. Motor control also plays an extremely important role in athletic performance. It has even been said that it could be the limiting factor. Esteemed sprints and jumps coach, Professor of Motor Learning, Frans Bosch, has put such an argument forward several times within the first chapter of his book. 
Our professions are telling us, and the world, that we’re experts in it. They’re swinging around to include the word “movement” in their vision statements, a word that requires mobility and control of it, that is, motor control. Some of our collective professions are including movement, and thus motor control, in their vision statements or strategic directions. The American Physical Therapy Association Vision Statement, in 2013 included “Transforming society by optimizing movement to improve the human experience.” The Australian Physiotherapy Association Vision Statement, adopted in 2012, states: “With scientific foundations, physiotherapists are experts in exercise and movement.” And Sports Osteopathy Australia’s Quality Practice Framework proposed in 2017: “Knowledge of fundamental movements, biomechanical requirements and ranges of movement required in general for risk minimisation in sport and athletic activities.”
The use of the word movement relates to what we as clinicians see in our evaluation. We see movement. That movement tells us whether the person has “necessary input, sufficiently processed, with an acceptable output”.  Motor control is the middle part – “sufficiently processed” – how the central and peripheral nervous system takes all the internal and external stimuli and organizes it for an appropriate response. That’s what we see when we evaluate movement.
Why is motor control not discussed more readily? The answer lies mostly in its perceived complexity and lack of perspective. So, let’s take the complex and simplify it. The understanding of motor control can be boiled down to four words:
Smooth. Easy. Jerky. Difficult.
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- Schmidt, R.A. and T.D. Lee, Motor control and learning : a behavioral emphasis. 3rd ed. 1999, Champaign, IL: Human Kinetics. xvi, 495 p.
- Schmidt, R.A. and T.D. Lee, Motor learning and performance : from principles to application. Fifth edition. ed. 2014, Champaign, IL: Human Kinetics. xx, 315 p.
- Dea, G. Regional Interdependence and Limiting Factors to Performance – Part 4. 2017; Available from: https://www.functionalmovement.com/Articles/787/regional_interdependence_and_limiting_factors_to_performance_part_4.
- Chapman, R.F., A.S. Laymon, and T. Arnold, Functional Movement Scores and Longitudinal Performance Outcomes in Elite Track and Field Athletes. Int J Sports Physiol Perform, 2013.
- Bosch, F. and R. Klomp, Running : biomechanics and exercise physiology applied in practice. 2005, Edinburgh: Elsevier Churchill Livingstone.
- FMSystems. SFMA Level 1. 2017; Available from: https://www.functionalmovement.com/system/sfma.
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