During this period, the growth rate of the skeleton is significantly increased to seven to ten centimeters, the body weight is up to four and a half to nine kilograms per year. Girls outstrip boys for one or two years in the rate of growth in length and body weight. The process of ossification has not yet ended. The length of the body begins to increase mainly due to the growth of the trunk. Developing muscle fibers, do not have time to grow beyond the tubular bones in length. The proportion of the body and the state of muscle tension change. In boys, after thirteen or fourteen years, muscle mass increases much more rapidly than in girls. At fourteen to fifteen years, the muscle structure of the fibers begins to approach the morphological maturity.
The heart intensively grows, its innervation rises, the developing tissues and organs impose increased demands on its work. The growth rate of the heart is much faster than the growth of blood vessels and therefore it can cause increased blood pressure and fatigue, as well as disrupt the rhythm of cardiac activity. The blood flow is hampered, so there may be a feeling of constriction in the heart and very often there is shortness of breath.
The movement of the ribs is limited by the morphological structure of the thorax, because breathing can be frequent and superficial, although breathing is improved and lungs grow. Also increases the vital capacity of the lungs and finally forms a type of breathing: the girls - thoracic, and boys - the abdominal.
Sexual differences between girls and boys affect the body's functionality and body size. Girls in comparison with boys become owners of a massive pelvic girdle, a relatively long body, short legs. All this reduces their abilities in throwing, jumping, running in comparison with boys. The muscles of the shoulder girdle are weaker than in the boys, and this affects the results in pulling, throwing, climbing, restraining, but at the same time they are better given plastic and rhythmic movements, exercises for the accuracy of movements and in equilibrium.
The nervous system and its functional state are under the enhanced influence of endocrine glands. In the adolescent period, fast fatigue, increased irritability and sleep disorder are characteristic. Very sensitive adolescents refer to unjust actions and decisions. External reaction by nature and strength is rather inadequate in comparison with the stimuli that cause them.
So, still, that is characteristic in the physical development of children of secondary school age. Boys very often can overestimate their motor abilities, trying to do everything on their own and understand everything themselves. Girls, much less confident in their abilities.
In general, adolescents are very sensitive to the assessments of adults, do not tolerate teachings, especially long ones, and quite sharply react to any infringement of their dignity.
At this age, when organizing physical education, it is undesirable to overload the musculoskeletal, muscle and joint-ligament apparatus. Since excessive loads can accelerate the process of ossification and provoke a delay in the growth of tubular bones in length. Performing exercises for flexibility requires conducting preliminary preparatory exercises that warm up ligaments and muscles, as well as exercises to relax the involved muscle groups. Do not perform too sudden movements. It is necessary to pay special attention to the correctness of posture. Exercises that have a significant load on the heart, you need to alternate with breathing exercises. It is not very good to tolerate a prolonged intense load, so it is recommended that intensive running alternate with walking.
It is also necessary to make extensive use of special breathing exercises to deepen breathing. To teach to breathe rhythmically, deeply and without a sudden change in tempo.
In no case can not be united into one group of girls and boys. Similar exercises for girls and boys should be performed in different conditions simplified for girls and with different dosages. The load must be dosed taking into account the individual characteristics of each adolescent. Girls are encouraged to use different types of exercises and aerobics performed to music.
The average school age - the tasks of physical education are:
- promoting healthy physical development and health;
- the need to develop the ability of motor qualities: speed-power, speed, muscle strength, endurance and mobility of joints;
- it is necessary to consolidate the skills of correct posture during movement and in static positions;
- the formation of a rational and complex life-applied, as well as a sportive kind of movements in a competitive and playful environment;
- training in basic techniques for performing individual athletics, gymnastics, swimming, skating and skiing, sports (volleyball, basketball, football, handball);
- familiarization with the basics of dosing the load and self-control during exercise.
The main means of physical education for secondary school age are exercises in throwing, cyclic exercises, climbing, jumping, overcoming horizontal and vertical obstacles, the fundamentals of the techniques of sports games, as well as new technologies in the field of motor activity: fitness and aerobics, etc.