Sensorimotor System – What does it mean

After hitting heavy traffic, turning what should have been a swift two hour car trip into an eventful six hour journey to Birmingham, we finally reached the Therapy Expo 2017!

 

Fuelled with coffee, we sat in on a number of interesting presentations. Although there was diversity amongst the guest speakers a common theme seemed to present itself, the role of the sensorimotor system in injury rehabilitation.

 

Steven Hawking said it perfectly when he stated:

 

“Intelligence is the ability to adapt to change”

 

The human body is of no exception. Our desire to move after injury sees that we will go to great lengths to keep our bodies mobile. Often completely subconscious, we find ways to move around pain, stiffness, or imbalances. Thus, compensatory movement patterns or “muscle patterns” are born.

 

Jo Gibson [Twitter: @shouldergeek1], well renowned shoulder rehabilitation specialist, whose lecture we were lucky enough to attend at the Expo, has been quoted to explain it like this in relation to the shoulder:

 

“Muscle Patterning refers to inappropriate recruitment, commonly of the torque producing muscles of the glenohumeral joint e.g. Latissimus Dorsi, Pectoralis Major, Anterior /Posterior Deltoid. This unbalanced muscle action is involuntary and ingrained. Patients with muscle patterning essentially have a muscle recruitment sequencing problem that results in abnormal force couples, destabilising the joint.”

It is an important topic, as failure to correctly diagnose a structural instability versus a functional instability is a common factor in patients failing conventional rehabilitation or surgery.

‘Rehabilitation in this situation should be aimed at ‘normalising’ muscle recruitment patterns around the shoulder girdle and this involves appropriate facilitation throughout the kinetic chain. Balance, coordination and core control are all factors that must be addressed to optimise neuromuscular control mechanisms.’(1)

 

Our ability to adapt to change is both the human body’s greatest strength and its biggest weakness.

As a short term strategy compensation is a great tool. It is protective against further injury and it enables us to get on with our daily function. However, when these newfound motor patterns become long term and supersede our normal programming we will at some stage hit a point of failure, which usually manifests as injury or failed rehab.

 

It can be explained like this…..

 

Your weekend football team is down a player and you have no choice but to replace your star striker with the goalkeeper. Chances are he will manage to get the job done for a period of time, but because his training has not been specific to the role of striker and he is not conditioned or well rehearsed to the demands of this position, at some point in the game he will fatigue, his reaction time will diminish and his ability to generate power and keep up with the pace of the game will become apparent, leaving him vulnerable to injury.

 

Similarly, if you delegate a task to a muscle that it is not designed for, it can deal for a time, but ultimately it will not be able to withstand the extra demands that have been placed upon it.

 

For therapists this is very important to recognise as it will guide how we structure our rehabilitation. When patterns become maladaptive and cemented centrally, rehabilitation takes on a different level of complexity. We are no longer treating an isolated system.

 

It is easier to learn than to unlearn a skill. My father always says, “Practice does not make perfect, perfect practice makes perfect”. As performing something in a sub optimal way over and over again only leads you further away from skill mastery.

 

So lets break it down….

 

What does sensorimotor mean?

 

The term sensorimotor system describes, ‘the sensory, motor, and central integration and processing components involved in maintaining functional joint stability’. This encompasses neuromuscular control and proprioception. (2)

 

Lets look at this in relation to a common injury such as an inversion injury of the ankle….

 

It is generally known that the primary risk factor for an ankle sprain remains a history of a previous sprain (5). It is thought that the initial damage to the lateral ankle ligaments alters the function of mechanoreceptors of these ligaments disrupting the ability to sense motion at the joint (4) and can lead to functional instability of the ankle. It is often described as frequent episodes of “giving way” or feelings of instability at the ankle joint.

 

A number of authors support the idea that some patients with functional ankle instability have deficits in neuromuscular preparatory or anticipatory control, which increases the risk of injury to the ankle, as it is less protected in an inadequate ankle joint position. Add to this a sub optimal rehabilitation program and paving the way towards a chronic ankle issue.

 

So what does this mean in terms of exercise prescription?

 

Benoy Mathew [Twitter: @function2fitnes] from Harley Street Physiotherapy during his talk regarding “the problem ankle” discussed the benefits of dynamic exercises such as sport specific plyometrics, which utilises sensorimotor training to promote anticipatory postural adjustments as well as optimise agility, landing technique and reaction time.

 

When it comes to overall running efficiency Mike Antoniades [Twitter: @runningschool], Performance & Rehabilitation Director of The Running School agrees:

 

“To change running technique, theoretical information and tips will not do the trick. The body needs to learn movement through movement – mostly while running but also through other re-patterning exercises”

(1)

 

During his workshop at the Therapy Expo, Mike gave us great examples during a live running assessment of particular movement dysfunctions that result from motor patterning, which often lead to muscle imbalances, poor technique and may be a factor in the recurrence of injury.

 

A common example is poor gluteal activation, which leads to compensatory hamstring dominance. Recognising this as the main offender of a patients running pain is a great start but strength training alone will only get you so far if it is a neuromuscular issue and ‘sensory motor amnesia’ is the primary reason why certain muscles fail to activate during movement.

 

There is a lot to think about during clinical diagnosis to ensure we are not ‘band-aiding’ a sensorimotor issue with strength exercises and manual therapy.

 

It is our responsibility as physiotherapists to ensure that we are continuously looking for opportunities to enhance our clinical skills. By optimising our assessments we are giving each person that seeks our advice the best opportunity to reach their full potential.

 

1. Antoniades, M (2016), Mikes view on therapy expo 2016. Retrieved December 10, 2017, from http://runningschool.co.uk/blogs/mikes-view-on-therapy-expo-2016/
2. Foundation of Sports Medicine Education and Research (1997). The role of proprioception and neuromuscular control in the management of knee and shoulder conditions.; August 22–24; Pittsburgh, PA.
3. Gibson, J (n.d), Advances in rehabilitation of the shoulder. Retrieved December 10 2017, from http://www.physioroom.com/experts/expertupdate/interview_gibson_20041031_1.php
4. Hertel J. (2002). Functional anatomy, pathomechanics, and pathophysiology of lateral ankle instability. Journal of Athletic Training. 37(4) 364–75.
5. Milgrom C, et al. (1991). Risk factors for lateral ankle sprain: a pro- 
spective study among military recruits. Foot Ankle. 12(1), 
26–30.
6. Lalazar & Vaadia, (2008). Neural Basis of sensorimotor learning: modifying internal models.  https://www.sciencedirect.com/science/article/pii/S0959438808001578

 

Bec van De Scheur