Dynamic Neuromuscular Stabilisation
Dynamic neuromuscular stabilization (DNS) is based on principles of developmental kinesiology i.e. the maturing human locomotor system. The approach views people with certain types of pain and dysfunction having defects in neuromotor programming. It also has applications in sporting and occupational performance. DNS was developed by Professor Pavel Kolar in the Czech Republic, who was in turn influenced by three other prominent Czech professors. It is practiced widely in many parts of Europe in mainstream clinical centres, but is largely unknown in New Zealand, hence the "non-mainstream" tag. It is a functional approach rather than the more traditional structural biomedical approach. It is an active therapy, where the patient is given home exercises to do, with guidance from the clinician.
Functional Rehabilitation Principles
- Restore diaphragm breathing and function
- Restore dynamic spinal stability
- Restore scapula stability
- Restore upper thoracic extension (T4) using deep flexors and extensors of the neck
- Restore lower limb functional stability and iliopsoas function
- Release the tight postural/tonic muscles, strengthen weak phasic muscles
Ontogenesis is a term that refers to the development of motor functions postnatally. When humans are first born the neurological and locomotor systems are immature, especially when compared to other mammalian species. As the central nervous system matures, postural foundations are increasingly established, with specific motor patterns at certain developmental milestones. The development of these motor patterns are genetically programmed rather than environmentally learned. There are three levels of postnatal CNS maturation with corresponding three levels of sensory-motor control.
In the neonatal period and first few weeks of life the spinal and brain stem control systems are dominant. There is functional and structural immaturity with no balance and no postural function. There is no synergy and coordination of the deep spinal stabilising structures to create a fixed point through the pelvis and trunk. There is excessive asymmetry, i.e. if the head is moved then the whole body moves. Without deep stablisation, there is anterior pelvic tilt, flaring of the rib cage, and elevation and protraction of the shoulder girdle. Primitive reflexes such as the Moro and sucking reflexes are positive.
At three months continuing to around 18 months we see integration of the subcortical region with the establishment of postural foundations and development of synergy, coordination, and timing. There is the development of fixed stabilising points through the trunk and pelvis. With these fixed points the larger muscle groups can work through them allowing isolated movements and we see less asymmetry. We see increasing synergy and coordination of the deep stabilising system allowing the child to reach higher and more unstable positions - from prone and supine positions (stablisation in the sagittal plane), to rolling over, crawling, kneeling, squatting, and eventually walking. Gaze fixation and somatosensory input also develop allowing increasing input from the environment. Primitive reflexes are inhibited in this time period.
From two to six years and beyond we see integration of the cortical system in the central nervous system. There is motor learning with selective movement, fine motor skills, agility, and motor dexterity.
There are many different ideas about what an ideal posture is. Despite differences in body shapes, every human has a central nervous system and has gone through developmental milestones. Ontogenesis shows us genetically determined ideal posture, and is automatic with healthy central nervous system maturation. For example the squat position of a 12 month old uses the same locomotor programme as a powerlifter doing a loaded squat.
The Integrated Stabilising System of the Spine
The integrated stabilising system of the spine refers to the integration of the deep stabilising muscles with other larger muscles groups. The deep stabilising system is a combination of the diaphragm, the pelvic floor, the entire abdominal wall, multifidi, and deep neck flexors. When there is synergy, coordination and timing of this system then even before any purposeful movement the diaphragm will first descend. The deep stabilising musculature will respond to the resultant increased abdominal pressure, a fixed point is created, and other larger muscles such as rectus femoris can then work off that fixed point. This is a "feedforward mechanism."
The diaphragm is the ring leader of the deep stabilising system. The diaphragm has three functions: respiration, stabilisation, and gastro-oesophageal sphincter function. It is anatomically related to the transversus abdominis. It works in conjunction with the pelvic floor, abdominal wall, iliopsoas, and multifidus. The diaphragm and pelvic floor act as partners in respiratory and postural function, and also both have a sphincter function. They must work in coordination as one functional unit.
This is different from bracing. Bracing is concentric activation the abdominal wall from the outside in, such as when preparing to be punched. It can provide stability but it doesn't allow good support with movement. Core stabilisation on the other hand is stabilisation from the inside out by increased intra-abdominal pressure and can help safely manage different movements and loading, and helps coordination of respiration and stabilisation. Dynamic stabilisation is in contrast to static stabilisation, and allows maintenance of intra abdominal pressure with movement and changes in loading.
Postural function proceeds and follows any movement, and is a dynamic function thus the name dynamic neuromuscular stabilising. It ensures the position of the trunk, spine, and pelvis during movement. It is controlled at the subcortical level and allows anticipatory brain activity to aid efficient purposeful movement. If postural function of the deep stabilising system is not optimal, movement can still be performed, but it can limit performance, overload the passive structures of the kinetic chain, and increase the risk of injury.
Neutral joint positions, known as "functional joint centration" in DNS terminology is a key concept in DNS. This is obtained with optimal function of the deep stabilising system. Functional joint centration has several advantages. It enables optimal loading with the most effective mechanical advantage. It provides the greatest interosseous contact allows optimal load transference across the joint. It also provides and ideal balance between agonist and antagonist muscles allowing for maximal muscle pull, and protection of passive structures.
Assessment and Treatment Approaches
The DNS approach focuses on assessing and training inefficiencies in the deep stabilising system. It aims to facilitate and reintegrate the hardwired genetic locomotor programme and utilises the positions of the developmental milestones. As adults the locomotor programme can become corrupted through postural habituation, repetitive motions, past injury, and pathological central nervous system maturation. Despite corruption, the potential for facilitation is still there.
Ideal core stabilisation corresponds to the muscular coordination of a 3 month old baby with the baby in a supine position with the hips flexed. Training instructions include maintaining a neutral (caudal) chest position, coordination of the diaphragm and pelvic floor, cylindrical activation of the abdominal wall, maintaining a neutral neck position, avoiding lordosis of the lumbar spine, actively maintaining a neutral hip position, and directing the patient's breath as far as the inguinal region and lateral dorsal aspects of the abdominal wall.
The clinician can use different methods such as manual therapy, cueing, and specific DNS active exercises to help facilitate correct activity of the deep stabilising system. Exercises are based on developmental kinesiology. They allow training of muscles during physiological function. They automatically activate ideal stabilisation function at the subcortical level.
- Main article: Dynamic Neuromuscular Stabilisation Examination
Several tests are used to assess a variety of parameters under the DNS concept:
- Compare individual postural locomotor patterns with developmental patterns
- Functional centration of individual segments with the ability to maintain individual body segments in a neutral centred position
- Evaluation of dynamic postural trunk stabilisation and muscle coordination responsible for stabilisation of the entire core
- Quality of spinal stabilisation of the spine, chest, and pelvis
- Dual role of the diaphragm in stabilisation and respiratory function
- Distribution of activation between superficial and deep stabilising muscles
- Symmetry and timing of activation of the spinal stabilisation muscles
- Adequacy of muscle activity under load
- Muscle compensatory mechanisms
- Spread of muscle activity to other segments of the body
Sport performance relates to power, strength, speed, and endurance. Sport technique is also required, and in order to facilitate technique, the athlete needs optimal postural foundations, optimal movement quality, coordination, and good cortical function with respect to body awareness. There is maximum demand on muscle activity, range of motion, loading of passive structures, and increased demands on the respiratory system. Training allows the body to adapt to increased loads, and aims to increase maximal performance.
Ideal locomotor strategies have a threshold, and this can come into play when pushing beyond ones limits. When this "functional threshold" is exceeded then the athlete will use more primitive stabilising strategies and there will be joint decentration. For example when doing a pull up and exceeding the capacity of the deep stabilising system the athlete will tend to hyperextend of the spine, protract the shoulders, and antevert the pelvis.
When going past this functional capacity, the athelete falls into the "functional gap". The nature of training is pushing into this functional gap, and using DNS principles in sport requires doing "threshold training," aiming to improve the athelete's functional capacity. If on the other hand the athlete frequently trains in the functional gap, then those high threshold compensatory patterns become the norm. Atheletes can be successful by working in the functional gap, but this can increase the risk of injury and prolong recovery, and reduce their true performance potential and longevity.
The following always needs to be assessed in sport:
- Centration/decentration of joints (movement segments) and deviation from neutral alignment
- Relationship between centration of distal and peripheral joints
- Timing between the function of stepping forward and support of the extremities
- Range of motion of the upper and lower extremities during stepping forward and support functions.
The same concepts used in sport can be applied to the occupational athlete. E.g. the labourer, the assembly line operator, etc. Just like the sporting athlete needs to train for their sport, so too should the occupational athlete train for their occupation.
In DNS assessment, the therapist compares the patients stabilising pattern to that of a healthy infant, utilising the knowledge of developmental kinesiology and what ideal deep stabilising utilisation looks like. Treatment is based on optimising the distribution of the internal muscular forces acting on each joint, taping into the hardwired genetic locomotor patterns. There is the potential for reducing the risk of injury and enhancing performance.