Physiological basis for the development of motor qualities
Muscles are the most important tissue in the body. Skeletal muscles are under direct volitional control and provide movement of the body in space and maintain posture. Regardless of the type of physical activity, the function of muscle tissue is the manifestation of contraction force and the use of the necessary energy for this.
Muscle strength depends on the cross-sectional area of muscle fibers and the degree of activation of the motor units that make up the muscle.
The increase in strength under the influence of training occurs due to two physiological mechanisms: due to working muscle hypertrophy and improved intramuscular coordination, which leads to an increase in the number of motor units that can simultaneously contract. In the case of muscle hypertrophy, it is necessary to strengthen synthetic processes in the muscle tissue itself. In the second embodiment, complex morpho-functional rearrangements affect mainly nervous tissue. As a rule, both processes proceed in a friendly manner, which allows for a properly set training process to observe a gain in strength.
Biochemical muscle strength
The biochemical strength of muscles is determined by the amount and activity of actomyosin ATPase, an enzyme located directly on the contractile apparatus of muscles. The higher the activity of actomyosin ATPase, the greater the power can develop the contractile apparatus and, accordingly, muscle strength.
Muscle fibers differ in myosin ATPase activity. Fibers with high AT-Phase activity are considered fast. They have a large cross-sectional area and are capable of developing greater strength. Muscle strength develops in ontogenesis heterochronously. A significant increase in the strength of most muscles occurs during puberty. At this time, the muscles undergo complex internal restructuring, differentiation of new and rapid development of existing muscle fibers and their apparatus innervating occurs. These changes occur not only as a result of the unfolding of the genetic program, but also under the influence of sex hormones, especially the male sex hormone testosterone and training.
In the process of strength training, the production of steroid hormones is enhanced. It is a natural stimulator of the growth and development of muscle tissue. This development is balanced, the muscles acquire all the necessary properties. Systematic strength training is best started at the age of 14-15 years. Recommendations to begin special permanent strength training from an earlier age are scientifically unfounded, insolvent and unhealthy. However, as one of the components of the integrated development of motor qualities, one can apply certain types of strength exercises from an earlier age.
Many children of primary school age, especially those related to the muscular-digestive type of physique, are happy to pull up and push up, perform elements of gymnastics. To a reasonable extent, this is permissible and useful.
Speed of movement
+ If we talk about the speed of movements, then the physiological processes underlying the manifestation of speed are very complex and diverse. First of all, speed depends on the greatest possible frequency of impulse of the nerve motor centers that control the reduction of motor units. However, a signal from the center will not have any consequences if it arrives at an unprepared implementing agency. By the time the next pulse signal arrives, the recovery processes (ATP resynthesis, etc.) in the muscle fibers themselves must be completed. This requires a very high activity of enzymes, primarily energy metabolism.
The contraction force of the antagonist muscles must be coordinated so that the accelerations imparted to the individual parts of the bone skeleton are optimal in magnitude and direction. It depends on the regulation of contractile activity by the motor centers. The speed of movement should be distinguished from the speed of movement. In the latter case, not only speed is important, but also the strength of a single contraction, the value of a one-time acceleration and, accordingly, the path that is overcome during one cycle. In its pure form, the speed of movements can be registered, for example, when changing the maximum rate of movements of the finger, hand, shoulder. Moreover, the greatest increase in the maximum frequency of movements is observed in the period from 7 to 9 years, and then in the period from 11 to 13 years.
These age periods are also most favorable for the development of the quality of speed. The differences in the physiological processes that occur as speed develops during these periods are that in childhood, mainly, intramuscular coordination is improved and the controlling effects of the nerve centers are worked out, and in adolescence, the increase in speed is provided by the restructuring of the energy supply of muscle contraction.