Muscle Reflexes (Posture Intensity)
Whenever a group of muscles are stretched that precise pattern informs the spinal cord via the muscle spindle. After a short delay, the same muscle pattern automatically contracts. This is what enables the body to move in complex patterns without any complicated thoughts.
The stretch is experienced simply as one sensation and therefor becomes easy to reproduce. The baby gets feedback easily by reproducing the sensory experience of the movement by contracting the group of muscles including the spindles via the reticulospinal tract, which is part of the gross motor system. The cortex at this point which controls the motion more precisely is not yet functioning.
Using reflexes to train moment is valuable for learning any sport, and it is quite likely that it would be impossible for an adult to learn how to move well without reflexes. This brings up the value of the therapist understanding the value of utilizing reflexes for examination and treatment. The reflexes are the foundation for all movement. First, the baby learns to turn on/off of the reflexes (which are technically no longer actual reflexes once the baby can alter them). Later, the large movement chain, which initially existed as one sensation, is broken down into a few pieces. This allows the basic movement to move in a sequential chain. Also, within any chain, there are three main components, being the power component like the deltoid and glute max, as well as the more stabilizing component like the trapezius/rotator cuff, etc. There is also a more precise component within the same chain. To test a movement, it first must occur evenly, then can be performed sequentially, with the power component taking its’ role in the chain. If a person can do that, the movement is functioning properly which also insures proper pain processing, circulation, no degeneration, etc.
However, if the movement was that pure they would never have come in to seek help. Those movements are altered for the protection of any injured tissue as the classic example of compensation. What happens is that potentially injured tissues inform the whole movement. The actual injured tissue might be inhibited (see golgi tendon reflex). Certain other parts of the chain are contracted to protect. The whole study of how the normal movement becomes protected involves different pieces, but by starting with the reflexes you are allowing the person to bypass all the protective mechanisms most of the time.
