Scientific movement, safe and efficient movement is not a simple jump, but a physical activity that must pay attention to science. Blind and reckless exercise will be counterproductive, and scientific exercise can be safe and efficient. Scientific physical exercise includes the following three aspects. (1) follow three principles. The three principles that scientific physical exercise should follow are ... comprehensive exercise, step by step and perseverance. Comprehensive exercise, first, let all parts of the body and various systems get exercise as much as possible; The second is to broaden the exercise items and forms as much as possible to develop various physical qualities. Step by step, that is, the intensity of exercise should be from small to large, and the requirements should be continuously improved on the basis of the gradual adaptation of the body; It also means that it is easy to learn movements and master techniques. Persistence is to form a habit and keep practicing until your whole life. (II) Considering Five Factors The five factors that should be considered in scientific physical exercise are ... one's own situation, exercise purpose, activity environment, project characteristics and amount of exercise. Your own situation. Practitioners are different in age, physique, health status, personality, technical level, study and work characteristics. Only from this reality can we determine the appropriate exercise mode and improve the exercise effect. For example, teenagers in the period of sudden height increase can practice stretching more, introverts should participate in group activities more, and mental workers can choose aerobic exercise that can promote brain cell activity and enhance cardiopulmonary ability. The purpose of exercise. When participating in sports activities, different purposes, contents, methods and loads will be different. Taking running as an example, if you are ready to participate in the competition, you need to have greater intensity; If it is fitness, low-intensity uninterrupted jogging should be adopted, and the duration of each time should not be less than 5 minutes; When the main purpose is to lose weight, the duration is preferably not less than 20 minutes. Activity environment. If possible, try to exercise in a place with fresh outdoor air and beautiful environment. In addition, it is also necessary to prevent accidents due to poor exercise environment. Select the project. Different exercise programs have different exercise values. If you want to lose weight, you should choose aerobic exercise that consumes obvious body fat, such as long-distance running and swimming. Amount of exercise. For ordinary junior high school students, moderate-intensity activities should be the mainstay. During the activity, the average heart rate should be kept at 130 times/minute, the exercise duration should be 40-50 minutes, and exercise 5-6 times a week, so as to obtain better exercise effect. (3) To carry out a set of routine scientific exercises, we should pay attention to three routines: ... preparation, activity guarantee and arrangement. Be prepared before the activity. Practitioners should check their bodies, wear appropriate clothes and shoes, and avoid being too empty during morning exercise. To see if the site is flat, outdoor activities must first understand the environment; Check whether the equipment is firm and reliable. Activity protection. In the process of activities, activities should be prepared according to the purpose and content of the activities; Strengthen self-protection and mutual assistance; Pay attention to self-feeling, distinguish between normal reaction and abnormal reaction, especially distinguish between two situations: you can continue practicing or you need to stop practicing as soon as possible. Tidy up. After the activity, we should do some tidying activities to make the physical and psychological conditions gradually return to normal, and take a shower and change clothes in time if possible. Life lies in sports, and sports should focus on science. I hope students can become active but cool-headed sports fans. The sufficiency and balance of nutrients in human body are related to the strength of immune system and some infectious diseases. According to the existing nutritional research results, supplementing nutrition to human body will greatly improve human immunity to diseases and play a role in preventing atypical pneumonia. So what is immunity? Immunity is simply the human body's resistance to various diseases, and the resistance comes from the immune system in the body. The immune system consists of immune organs (such as thymus, bone marrow, spleen and lymphoid tissue) and immune cells (such as macrophages, natural killer cells and lymphocytes). A sound immune system has three major functions, one is defense. Strong immunity, can help the body eliminate foreign bacteria and viruses, avoid diseases, and have the defense ability to protect the body from harm; The second is the stable function. Good immune function can help the body to repair or remove dead tissues and cells that are metabolized, damaged or aged in the human body, and keep the internal environment of metabolism in a stable state all the time; The third is the monitoring function. Strong immunity can help the body kill and eliminate abnormal mutant cells. Only when all the functions of the human body reach a balanced state can health be guaranteed, and the nutritional status of the body is closely related to the strength of immune function. In the process of supplementing nutrition, we should pay attention to ensuring the immune ability of the body through balanced nutrition. Three steps of nutrition and immune balance How do several typical immune-related nutrients construct the human nutrition-immune system? First of all, the combination of "VA+Zn" (vitamin A plus zinc) constitutes the first step of the trilogy of balancing nutrition and immunity, which can help prevent viruses from entering the human body and prevent respiratory tract infection. Medical experiments show that vitamin A is an essential substance to maintain the normal function of epithelial tissue, which can promote the differentiation and repair of epidermal cells such as respiratory tract, ensure the integrity of epidermis, and thus resist the invasion of germs. Vitamin A is called "anti-infective vitamin". The synergistic effect of zinc and vitamin A can improve the absorption and operation of vitamin A. Therefore, the simultaneous effect of vitamin A and zinc can effectively prevent the virus from invading. Vitamin C, the second step of constructing a trilogy of balanced nutrition and immunity, helps to kill viruses that enter the human body. Because it can interfere with the virus invading white blood cells, activate white blood cells all over the body, enhance the phagocytosis of white blood cells to viruses, and kill germs, thus enhancing human immunity and protecting human body from viruses. The content of vitamin C in leukocytes of patients with cold decreased obviously. In addition to trace elements, there is taurine. Taurine is an amino acid, which can promote the growth and reproduction of immune system lymphocytes. In addition, it can clear away heat, relieve pain, and relieve the symptoms caused by the self-regulating defense system initiated by the human body to resist viruses-fever, which is the third step of the trilogy of balancing nutrition and immunity. When the human body is seriously injured, taurine also plays the role of clearing away heat and reducing fever, thus enhancing the body's resistance. That is to say, if people, especially children, can supplement a variety of nutrients that are beneficial to improving human immunity in a balanced way and build an immune protection barrier, they can effectively protect the body from viruses.