Prevention better than cure? Neuromuscular control
This is a quality guest post by Chris Tack from All Powers Physio. Chris has impressed me with his blog examining combat sports training from a physio perspective. He works with fighters in the London area and trains in MMA too. This article is a good overview of the common injury mechanisms. Make sure you leave a comment below to let us know what you think about it.
Prevention better than cure? Neuromuscular control
There are two main mechanism types sporting injuries fall under- Traumatic and non-traumatic.
In this definition, trauma would consist of an injury due to an external violence or incident whilst performing sport.
Traumatic injuries can occur in most sports but obviously are more prevalent in combat sports such as mixed martial arts and in contact sports such as rugby or American football. These types of injuries can not be prepared for in the most general sense, and the only groundwork an athlete can do, in an attempt to leave them better conditioned for such as injury, is to ensure their diet and training are at a high standard to ensure their musculoskeletal system is ready to heal at as proficient a rate as possible.
Due to their nature these injuries are very diverse and can occur to various anatomical sites. The sport you undertake will leave you in varying degrees of risk for specific injuries. For example, in mixed martial arts (MMA) due to the varied styles and techniques utilised, there is a greater variety of injuries types across body areas than in football (soccer) which leads to a higher percentage of lower limb injuries (such as groin, knee and ankle problems). In MMA there is just as much of a chance that you would injure your elbow at the hands of a well executed arm bar, than you would break your metatarsals when striking the head of an opponent with a head kick. The style of fighting, game plan, strategy and skill of the MMA athlete would predispose them to various risks dependent on the way they fight.
Non-traumatic injuries will be the main focus of this article as these are the types of injuries we can prepare and in the best case prevent. All the professional athletes I have a hand in training will incorporate certain elements to their training to attempt to avoid this type of injury. This form of “prehabilitation” is essential for elite performers.
The first sub group of non-traumatic injuries we will discuss is incidental injuries. The mechanism behind this type of injury is not to be confused with traumatic injuries but does obviously involve a specific incident or occurrence during sporting performance.
For example, when a wrestler shoots for a double leg takedown, a component of the technique is the transfer of weight inferiorly and the change of levels to allow efficient force translation forward to the legs of his opponent. This requires a fast but controlled descent into knee flexion (squat position) before a powerful knee and hip extension to “shoot” at your opponents legs.
If during this technique the wrestler’s foot slips or is caught on the wrestling mat, causing his knee to twist and torque such that it causes a knee ligament sprain, this would be considered in this definition as a traumatic injury. The mat or lack of friction which causes the injury is the external cause of the trauma. However, if the rotation torque of the knee is due to a lack of muscle control at the knee or pelvis then the deficiency is an internal characteristic of the athlete and as such means this injury is incidental.
Motor Control- Case example
Whilst there are a number of internal musculoskeletal deficiencies which can lead to injury in the wrong circumstances, the most common deficit is in what is labelled neuromuscular control.
Neuromuscular control (NMC) is essential for all muscles and involves the relationship between various muscles activation speed, strength, endurance and frequency of firing- and as such is dependent upon effective neural (nerve) activation and control by the central nervous system. In a nut shell it is the ability of muscle groups to effectively control the joints of the skeletal system and move the bones of the skeleton, in as efficient way as is possible. Correct sporting performance technique is underpinned by effective and efficient biomechanics due to correct NMC.
Muscles are characterised by their role in firing and what they have control over. Some muscles are agonists and have a specific role in causing a certain movement. For example, the biceps brachii muscle is the agonist which causes elbow flexion.
Each agonistic force has a conflicting muscle which is the antagonist which opposes the movement. The conflicting force working against the biceps to prevent excessive elbow flexion is obviously the triceps.
The other type of muscles is the synergists. These are able to activate to assist the motion caused by the agonist but do not provide sufficient force to be a primary mover of a joint.
NMC is the ability of the nervous system to control the roles and activation patterns of varying synergists and agonist/ antagonist muscle pairs to ensure efficient motor behaviour. In a general sense when there is alteration or imbalance in these motor patterns the body is put at a higher risk of suffering injury.
In our example of the wrestler this could be apparent. As the wrestler flexes his knees into a squat he is eccentrically contracting his various quadriceps muscles to lower his body weight into the bent knee position. His hamstrings are activated to prevent his knees extending (antagonist), as his rectus femoris muscle moves him through range from full knee extension to 90° flexion. The coordination of the different quadriceps muscle groups and fibres is controlled by automatic patterning of nerve impulse firing. However, if there is a deficiency in one or more muscle groups then the coordination of those muscles changing from their role as a temporary agonist to a synergist can lead the body part to lose its efficiency of motion.
This occurs commonly in the knee due to reduced activation of the vastus medialis oblique muscle. The majority of the normal population do not have excellent activation of this muscle but do not stress the knee enough for it to be a problem. This muscle controls the last 15° of knee extension (straightening) and as such, in our example, would eccentrically control the first 15° of knee bend. As the wrestler lowers into a squat, as he moves from 15° to 20° knee flexion, if this muscle is not properly activated and working as a stabiliser for the knee then his body weight could be transferred wrongly through the joint. If acting with increased speed and intensity then this increased load through the joint and could potentially cause a rotational moment and lead to a twisting injury on the knee.
Motor Control- General Factors
Obviously NMC is important for all body parts in order to prevent our body being placed into a position where it is at risk of biomechanical disadvantage.
Common patterns can occur also in the shoulder and lumbar spine region for example.
In the shoulder the deficient pattern of muscle activation lies within the rotator cuff muscle group in their ability to sustain control over the head of the humerus (upper arm) bone. Their synergistic role is counteracted by a compensatory activation of larger agonist muscle groups (such as the pectorals).
In the lumbar spine control of the normal spinal lordosis curve is lost when the lower abdominal muscles (transverse abdominus) and deep spinal extensor muscles activation is insufficient, and prime movers such as the erector spinae and quadratus lumborum become more dominant in their firing pattern.
The role of physiotherapy or any treatment post injury would be to deal with the healing process occurring; reducing pain; to prevent any compensatory strategies becoming deep rooted physical behaviours; and to then re-establish correct motor patterning to prevent reoccurrence.
It is essential for all personal trainers, strength and conditioning coaches and even individual athletes to examine their levels of neuromuscular control and the intricacies of their technique during sporting performance in order to PREVENT injury.
Can the individual control neutral lower limb alignment during a squat? If they can then you challenge them further (single leg, unstable surface, adding perturbations to their control through weight transference/ body position). Establishing the ability to have excellent proprioceptive control of their body parts is an essential characteristic of elite athletes and is entirely due to their high levels of NMC.
The key approach is to identify potential areas of NMC through isolated control testing and then examination of performance via video tape or in real time. The goal is then to break down the activity to manageable steps which you can use to slowly develop the correct motor control mechanisms.
For example, if you see that your athlete hyper extends his lumbar spine during a front kick technique, he may be predisposing his loading patterns through his spine to cause excess stress on his intervertebral discs and to overactive the pattern of lumbar spine extensor muscle firing. This may lead to him suffering back pain.
It is your role to firstly identify this physical behaviour and then break down the activation pattern. For example, can he dissociate his lumbar spine from his pelvis in supine through a pelvic tilt? Can he then sustain that control during a bilateral bridge (therefore maintaining abdominal activation during hip extension)? Can he translate that control and ability to move in sitting or standing? Can he then flex his hip (mimicking a front kick motion) when his lower abdominals consciously activated? Can you then provide a perturbation to that position in order to challenge his control (e.g. standing on a bosu/ wobble cushion)?
The rest is repetition and close scrutiny during performance. Ensure that the athlete can sustain their progress during bag work and then analyse them during sparring. If you find they return to the previous behaviour go back a step and continue with further repetitions and further challenge through adding more difficult perturbations.
The other form of non-traumatic injury to be aware of is non-incidental injuries, which are in effect an extension of the movement patterns and behaviours which can take root if not identified early enough.
These are the long standing and degenerative patterns of loading and force which we see after long periods and multiple repetitions through daily life. You may see, for example, a deficiency of gluteal activation patterning within a part time athlete who also works full time in a desk based sedentary job. The extended periods of sitting can lead to muscular imbalance around the hip, pelvis and lumbar spine, which if not counteracted can result in muscle atrophy and abnormal loading through the spine and lower limb.
Generally these cases are likely to need to follow the same treatment approach as incidental injuries, however due to anatomical changes over time, do not have the same prognosis. Their compensatory behaviours are likely to be more ingrained into their ways of moving and performing activity, and as such will require much greater practice to break.
The best tip is to continuously examine your own performance and that of your teams to be best suited to identify abnormalities when they occur. Ensure neuromuscular control exercises which are sport or activity specific are a part of your fitness regime and continue to challenge your self to keep progressing.
Stay healthy & keep fighting