Bodybuilding is a purposeful and planned teaching and exercise process based on human science, which exercises healthy physique, trains manners and instruments, and cultivates moral quality through bare hands or equipment practice. I. Contents of Physical Exercise Physical exercise is a complete and systematic exercise system, and its contents are divided into the following aspects according to the parts and functions of exercise: (1) Correct sensory training of various parts of the body is one of the necessary conditions for forming and maintaining a beautiful body, including the head and neck, trunk, upper limbs and lower limbs, and the basic posture of standing. It is an indispensable part of physical exercise to experience the muscle sensation necessary to maintain the correct posture of the body and improve the self-control ability of the body through sensory exercises in various parts of the body. (2) Basic body exercises Basic body refers to the innate body and the most basic body posture shaped after birth. Its exercises include basic direction, basic parts, hand holding posture, hand holding posture and expressive force. In the practice of basic posture and basic parts, the cognition of direction is standardized for the basic parts of feet and hands; In the hand-holding exercise, arrange the exercise content according to the physical condition of ordinary college students and put forward the normative requirements; Unarmed posture exercises, including various basic footwork and arm movements, emphasize the beauty of gestures and are rich in content; The expressive exercise focuses on cultivating people's graceful posture and the ability to express emotions with body movements and facial expressions, which is one of the most important exercises in body exercises. (3) Basic quality practice Basic quality is a necessary condition for controlling and maintaining body posture. In this part, flexibility, strength and coordination are selected, and their exercise methods are introduced in categories. Second, the characteristics of physical exercise Compared with other sports, physical exercise has different characteristics. Only by understanding these characteristics can we give full play to the role of physical exercise, choose exercise methods purposefully and pertinently, and achieve the purpose of effective exercise. (1) Physical exercise contents suitable for practitioners at different levels are compiled according to the physiological and psychological characteristics of teenagers and the needs of teenagers at different ages, and according to the law of action formation. The contents are divided into three groups: high, middle and low. (2) Effective physical exercise for all parts of the human body pays attention to the method of combining whole exercise with partial exercise in content, which provides conditions for comprehensive and focused exercise and "carving" the human body, which can not only enhance the muscle control ability, but also cultivate correct sensory perception, exercise a certain part of the body or develop a certain quality, and further improve the health level of the body while exercising physical beauty. (3) It is human nature to satisfy teenagers' desire for beauty. Nowadays, teenagers demand not only better health, but also more bodybuilding. Physical exercise is to consciously inject the meaning of "beauty" into the exercise, based on human science, and improve muscle control, movement expression, coordination and flexibility through various exercise means and methods, so as to obtain a bodybuilding posture and a healthy body. Satisfy teenagers' desire for beauty. (4) There are certain artistic requirements. Physical exercise requires accuracy, coordination, large amplitude, strong sense of rhythm and beautiful posture, and requires practice accompanied by music. Both local exercises and overall exercises should fully reflect the rhythm and feeling of beauty, and fully reflect the artistic requirements of dynamic beauty and static beauty in the process of completing exercises. (5) It can cultivate people's inner temperament. "Sports create human beauty, not only by shaping the body, but also by instilling a cheerful, open-minded, sincere and enterprising spirit into people's hearts through sports, so that people's actions and gestures are full of beautiful charm, thus truly demonstrating the cultural quality of the human body. Generally speaking, teenagers who have undergone systematic physical exercise are not only well-proportioned, but also well-behaved, sitting, standing and walking gracefully, which can fully show their youthful vitality. The physical beauty obtained through physical exercise can reflect a person's mental outlook and temperament, and it is a window to show people's inner beauty. Three. Adolescence is a key stage of physical growth and development, and it has not yet been finalized. Great plasticity is the key period to form a good figure and posture and improve bodybuilding. Therefore, we should seize this opportunity and follow the following exercise principles to carry out aerobics exercises for a long time, systematically and scientifically. (1) Purpose Principle The enthusiasm of physical exercise comes from clear purpose and correct motivation. Therefore, we should first carry out regular ideological education and link the purpose of physical exercise with improving the quality and national image of the whole Chinese nation and promoting the correct development and health of the body. The determination of this goal is helpful to generate positive emotions and consciously overcome various difficulties encountered in the practice process. Secondly, at every stage of physical exercise, we should strive to achieve the expected goals. Physical exercise is a long-term task, and it is not easy to produce obvious changes in the short term. Therefore, there should be clear purpose requirements in each practice stage, and these requirements should become the expected goals of the practitioners. For example, leg flexibility exercises should aim at vertical and horizontal splits, and each exercise combination aims at mastering movements, thus making practitioners interested in the content. Interest itself will promote practitioners to practice actively. Through the combination of class and class, physical strength and brain power, it will inevitably have a good influence on the body, and then change in body shape and temperament. In this way, practitioners will feel rewarded and play an important role in mobilizing and consolidating the enthusiasm of practitioners. (II) The principle of proceeding from reality The principle of proceeding from reality is to formulate corresponding practice plans and select corresponding practice contents according to the different ages, genders, physical foundations and practice levels of practitioners. So that practitioners can effectively stimulate all parts of the body in the process of participating in sports, and are not afraid of difficulties or excessive fatigue. For example, when dealing with children, we should choose a combination of exercises with lower difficulty-focusing on basic quality exercises, focusing on all-round exercises, and appropriately selecting content with strong gameplay; For teenagers with a certain foundation, we should choose the movements in the middle and high difficulty group-mainly local exercises, mainly carving various parts of the body, and crossing the grip and leaving the grip. At the same time, we should combine general requirements with differential treatment, put forward general requirements for the similarities of people at the same level, and treat everyone's differences differently. Such as the number of exercises, time, feeling of action, etc. (3) Adhere to the principle of regularity. We must adhere to the principle of regularity and persevere, so that various effective methods in physical exercise will have a lasting impact on all parts of the human body, gradually forming a "habit" and making all gestures reflect a "behavioral beauty". "Teenagers should have enough time for physical exercise. Conditional schools should set up physical education class at least twice a week to ensure that students have enough time to receive comprehensive and systematic exercise during their school days. This not only helps students to correctly understand the standard requirements of body posture in concept, but also helps students to master the methods and means of physical exercise in practice, and also helps to form biological rhythm, so that the human body can gradually adapt to and prepare for participating in exercise, further improving the effect of exercise, which is of great significance to cultivating students' idea of "lifelong sports". (4) The principle of step by step In the teaching process of physical exercise, we must follow the principle of from easy to difficult, from simple to complex, and gradually improve the teaching difficulty and requirements. Reasonable and orderly arrangement of contents, methods and exercise load should reflect the objective law of physical exercise teaching process. Specifically, warm-up activities should be carried out before class, and then the content to be practiced should be carried out, so that practitioners can enter the practice in the best state, enhance their acceptance, improve the practice effect, and prevent injury accidents; At the end of the course, there should be relaxation activities or games, so that practitioners can eliminate fatigue as soon as possible and produce happy emotions. For those who have just participated in the exercise, they should pay attention to the content of basic exercises, and gradually put forward new requirements with the continuous improvement of physical fitness and sense of action, and gradually transition to higher-level movements. (5) Comprehensive principle Aerobics should comprehensively develop all parts of the body, all kinds of physical qualities and basic activity ability, and carefully "carve" every part of the human body. Teenagers are in the stage of growth and development, and physical exercise should strive to influence the human body in an all-round way, highlight the key points in different stages and give consideration to other aspects. At the same time, it is necessary to combine physical exercise with the cultivation of inner temperament, so that teenagers can have a correct aesthetic consciousness through physical exercise, even if they are well developed and have an elegant and refined temperament, they can grow up healthily in a beautiful artistic environment, making physical exercise an effective means to improve the comprehensive quality of teenagers.