Passive Mobilisations: Primary Therapeutic Effects

Elongates contracted connective tissues: Movement encourages the normal turnover of collagen and its alignment along the lines of mechanical stress. This adaptive reorganisation provides the tissue with better tensile properties. Movement improves the balance of glycosaminoglycans and water content within the tissue which helps maintain the interfibril distance and lubrication. This reduces the potential for abnormal cross-links formation and adhesion.    

   

Pain gate: Nociceptors (small diameter fibres) block the inhibitory neurone and excite the projection neurones. Therefore the inhibitory interneurone cannot block the output of the projection neurone that connects with the brain - gate is open. Large diameter fibres excite the inhibitory interneurone and also the projection neurone, therefore the inhibitory interneurone can block the output of the projection neurone - gate is closed.

Passive mobilisations stimulate mechanoreceptors located within joint capsules and ligaments. Information travels faster via large-diameter fibres (mechanorecptors), their stimulation causes them to arrive faster at the spinal cord, thereby inhibiting the pain messages from small-diameter fibres (nociceptors).

Speed of Conduction

Nociceptors:

C fibres - travels at a rate of 0.5 - 2 metres per second (unmyelinated)

A delta fibres - travel at a rate of 5 - 15 metres per second (thinly myelinated)

Mechanoreceptor:

A beta - travels at a rate of 30 - 70 metres per second (myelinated)

Myelin - an insulated sheath around an axon; consists of multiple layers neuroglial membrane; significantly increases the impulse propagation rate along the axon (saltatory conduction).

*Also action potentials are conducted quicker along axons with bigger diameters because there is less resistance to the flow of ions than in the cytoplasm of a smaller axon.*

 

Facilitates the trans-synovial pump:

Movement (active or passive) activates the trans-synovial pump which facilitates the formation and drainage of synovial fluid in the joint. On one end of the pump movement causes increased blood flow around the synovium (which is important for the formation of synovial fluid) and on the other end of the system, it stimulates drainage into the interstitial spaces (lymphatic system). Movement also alters the intra-articular pressures within a joint; an increase in the intra-articular pressure produces an outflow, while a decrease in the intra-articular pressure increases the influx into the joint cavity.

Joint swelling is the primary cause for stiffness and reduced range of motion post-injury. Early mobilisation will help reduce joint swelling by activating the trans-synovial pump and draining the oedamatous peri-articular structures.


Other therapeutic effects include...

• Facilitation of the healing process
• An improvement in neurodynamics
• Temporary muscle inhibition