Analysis:

Middle and long-distance running is a long-term endurance project, and long-term continuous muscle activity is the characteristic of this project. On the one hand, it requires to minimize energy consumption and maintain a certain running speed, on the other hand, it requires to have the ability to accelerate the running according to the situation of the competition in the whole running. Therefore, it is very important for athletes to master the skills correctly and distribute their physical strength reasonably during the whole running. It requires easy and coordinated running, stable center of gravity movement, strong linearity and good rhythm; We should try our best to improve the ability of alternating muscle exertion and relaxation, not only pay attention to the action effect, but also pay attention to saving physical strength These requirements, the longer you run, the more important it becomes. Middle and long distance running is an endurance exercise, and it belongs to periodic exercise from the technical structure. It is necessary to repeat every step of running continuously for a long time. It is restricted and influenced by long-term continuous activities, so its absolute speed is not as fast as that of sprint, and it has the characteristics of medium-speed running. Conceptually, however, we must never think that middle-distance running is equal to middle-speed running. In fact, middle-distance running is also a fast running, which is the fastest running at a certain distance, and is usually called endurance running. Only by showing speed in endurance running can we run faster in the distance of middle and long distance running and show the characteristics of middle and long distance running substantially. In the practice of middle and long distance running, the regular characteristics of muscle activity have explosive contraction characteristics. In order to achieve explosive contraction, the muscles must be stretched in advance, and the muscles must be stretched in advance, and the muscles must be relaxed. Relaxation is a very important prerequisite, and it is a condition required to achieve the ideal degree of technology in middle and long distance running. Therefore, the consistency, softness, smoothness, naturalness and rhythm of the technical movements of middle and long distance running must focus on mastering the ability of relaxation in teaching and training. Relaxation and degree have a functional relationship with mastering the technical movements of middle and long-distance running, saving effort and achieving good results. Middle and long distance races need to run faster in longer paragraphs. Must have obvious rhythm characteristics, rhythm disorder, heart rate disorder and muscle exertion disorder, so that energy consumption, physical waste, slow down, can not meet reasonable requirements. The sense of rhythm and speed is the embodiment of the concept of time and space in long-distance running events, and the average and reasonable physical distribution reflects the characteristics of middle-distance running events. The sports level of modern middle and long distance running has been continuously improved, the world record of middle and long distance running has been continuously broken, and its running speed is getting faster and faster. The characteristics of the event are that the central nervous system and muscle activities should be continuously accepted for a long time, and the human body needs to consume a lot of energy to maintain the high speed required for the competition. Due to the improvement of speed, its action structure tends to the technical development of sprint. With the increase of back-pedaling strength, the back-pedaling range is increased, the back-pedaling time is shortened, the movement speed of back-pedaling is gradually accelerated, and the back-pedaling angle is reduced. It is more obvious to stretch in the sequence of hip, knee and ankle, and the forward distance of the body's center of gravity is lengthened in the whole process of back-pedaling, and the coefficient between the flying stage and the supporting stage is getting closer and closer. The complete technology of middle-distance running shows that the movement is relaxed and natural, the center of gravity moves smoothly and the forward effect is good. With the appearance of modern plastic track, the technology of middle and long distance running has made new development. In order to adapt to and make better use of the elasticity of the plastic track, the swinging legs swing forward more vigorously during running, emphasizing that the swinging speed is accelerated, the swinging force of the swinging legs is increased, the swinging direction is more forward, and the landing action is more active, while the feet are actively pushed back in the supporting stage after landing, and the time of exerting force is shorter, especially paying attention to reducing the consumption of the back pedal force. The success of contemporary middle and long distance running depends entirely on the average step length L and the step frequency F, that is, V = L F. Therefore, the purpose and task of running technology itself is to strive to achieve the maximum step size and step frequency or a reasonable combination of the two. Generally speaking, modern middle and long-distance running technology is still developing on the basis of two characteristics: economy (labor saving) and effectiveness (speed). The trend of middle and long-distance running technology appearing in the competition field is to develop in the direction of high speed, high frequency and economy.

Fitness long-distance running can improve the function of respiratory system and cardiovascular system. Scientific practice has proved that long-term rhythmic deep breathing can make people breathe a lot of oxygen, and if the amount of oxygen absorbed exceeds 7-8 times of usual, it can inhibit the growth and reproduction of human cancer cells. Secondly, long-distance running exercise also improves the oxygen supply state of myocardium, accelerates myocardial metabolism, and at the same time thickens myocardial muscle fibers and enhances cardiac contractility, thus improving the working ability of the heart.

Second, fitness long-distance running is conducive to disease prevention and treatment. Fitness long-distance running accelerates blood circulation and cleans harmful substances in the excretory system, making it difficult for harmful substances to stay and spread in the body. According to the measurement, 16 minutes running 3000m or 25 minutes running 5000m can reduce blood cholesterol. This has a good preventive effect on the elderly who are prone to different degrees of hyperlipidemia, which in turn leads to arteriosclerosis, coronary heart disease and cerebrovascular disease.

Third, fitness long-distance running is conducive to a comfortable mood and a happy spirit. This kind of long-distance running is very beneficial to alleviating the mental and psychological tension brought about by high-tempo and intense sports in modern society because it does not pay attention to the outcome of the competition, but only seeks to exercise in a relaxed and happy way. According to medical experts, this kind of relaxed and pleasant exercise can best promote the release of a polypeptide substance-endorphin bark in the body, thus making people have a lasting euphoria and sedation. In addition, because long-distance running makes people full of optimism, it helps to increase appetite, strengthen digestive function and promote nutrient absorption.

Long-distance running exercise plays a good role in cultivating people's tenacious will to overcome difficulties and temper hard work. Especially for those who are afraid of the cold in winter and love to sleep late and don't want to exercise, so that people can taste the benefits of long-distance fitness exercise.

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