The influence of massage
There are three types of specialized receptors in human muscles: primary endings of spindles, secondary endings of spindles and tendon receptors of Golgi. These receptors react to mechanical stimuli and participate in the coordination of movements, being a source of information on the state of the motor apparatus.
Muscle spindles are small elongated formations located in the thickness of the muscle( Fig.).Inside the capsule of each spindle is a bundle of muscle fibers. These fibers are called intrafusal, in contrast to all other muscle fibers, which are called zykstrafusalnye. Veretena are located parallel to the extra-fusal fibers, so when stretching the muscle, the load on the spindle increases, and when it decreases, it decreases.
Fig. The structure of the muscle fiber and its innervation.
1 is the proximal end of the skeletal muscle attached to the fiber;2 - distal end of this fiber attached to the fascia;3 - nuclear bag;4 - afferent fibers;5 - efferent fibers;6 - motor fiber going to the skeletal muscle.
Veretena react to two types of action: a change in muscle length and a change in the level of activation of the efferent fiber system. When the passive muscle is stretched, activation of receptors( muscle spindles) is observed.
Veretena can be considered as a direct source of information about the length of the muscle, about its changes, unless the muscle is excited. With the active state of the muscle, it is necessary to take into account the influence of the system that supports the spindle shortening of the shortening muscle, which makes it possible for receptors to respond to disturbances caused by interference by both increasing and decreasing the pulse frequency and thereby participating in the correction of movements.
By stretching the muscle, the masseur achieves increased impulse from the muscle spindles to the corresponding segments of the spinal cord, thereby increasing the tone of the nerve center that controls the activity of this muscle. The question arises: why, despite the fact that the use of any massage techniques causes an increase in impulse from the receptors of muscle spindles or mechanoreceptors and, as a consequence, an increase in the tone of the corresponding parts of the central nervous system, apart from the exciting effect of the massage, are its inhibitory effects differentiated? This phenomenon can be explained by one of the properties of nerve centers, where all information about external influences on the organism and its internal state comes.
The nerve center( functionally) is understood to mean a set of neurons located in different parts of the central nervous system and combined by performing a single function. Each nerve center has its own receptive field, that is, that part of the skin, a group of muscles, etc., where information comes from. If you stimulate a nerve center with an optimum pulse frequency for a short time, then it will go into a state of excitation, which will accordingly reflect on the state of the part of the body whose function it provides. If, however, the number of pulses is too great or they come for a long time, then in the nerve center a deceleration, called "inhibition after excitation," will develop. This is due to the functional features of the neuron membrane and the properties of the interneuronal synapses, that is, the places of transmission of excitation from one nerve cell to another. Thus, the use of surface massage of medium duration allows to increase excitatory processes in nerve centers, and the use of a deeper massage with a gradual increase in the force of influence promotes the development of inhibitory processes, that is, "inhibition after excitation."Apparently, it is possible to achieve a bremsstrahlung effect with a surface massage, but this would take much longer. Of course, it should be borne in mind that the structure and nature of the body's response to massage each time are different depending on the ratio of the processes of excitation and inhibition in the cerebral cortex, the functional state of the receptor field that undergoes a massage, the state of fitness, the nature of the massage andused techniques. The effectiveness of massage depends on the knowledge of the massage the functional state of the massaged.
To the group of proprioceptors, in addition to muscle spindles, articular receptors also belong. They are located in the articular bags and in the ligamentous apparatus.
In the articular bags there are receptors, in which the frequency of discharges varies in accordance with both the position of the joint at rest and the speed of its movement. Histologically, they are receptors of the Ruffini type. The ligaments contain receptors similar in shape to the Golgi bodies, and a few corpuscles similar to Pacini's bodies. In addition, there are free nerve endings, the function of which is still unknown. They assume that they are involved in the transmission of pain signals from the joints.
When the masseur performs passive movements in the joints, the articular receptors are stimulated in the joint and a chain of processes similar in their physiological mechanisms with the features of the transfer of nerve impulses from muscle spindles and mechano-receptors discussed above is initiated.
In conclusion, devoted to the physiological effects of massage on mechano- and proprioceptors, it should be noted that in them the influence of massage was considered only from one side - from the point of view of the neural-reflex theory. However, as mentioned earlier, the effects obtained with the use of massage techniques can be explained only when taking into account the complex effect of massage on the body. To obtain a more complete picture of the physiological effect of massage, it is necessary to consider other aspects of its effect.