Many teenagers have been at home for a long time. They stay at home and sleep after eating. Their physical fitness is generally not as good as before. If you don't exercise again during the winter vacation, the children's physical quality is really worrying. How to let the children after "Yang Kang" recover their exercise scientifically has become a difficult problem for many parents. The current situation has changed from passive residence to active residence, and the lack of physical fitness has declined. Since last November, home online classes, high school student Xiaoyan has started a long "home life". "At first, the children still wanted to play basketball with friends, but during that time, the epidemic situation became more and more serious, and they were worried about infection outside, so they were forced to stay at home, and basically did not go out except for nucleic acid." Xiaoyan's mother found that although the school's online classes were also arranged with physical education classes, the requirements were not strict. "The children did not take it seriously, and fooled over." After a while, Xiaoyan felt that it was unreasonable to go on like this, so he used the fitness equipment at home to do some exercises. "I pulled a few pull-ups, did some push-ups, and then came three or four groups of high leg lifts. As a result, I couldn't breathe and told me that I was tired in bed." The next day, Xiaoyan's mother noticed that her son had a cough. Soon after that, Xiaoyan became the first "Yang" in the family. "Now he is even more afraid to exercise. Even if it turns cloudy later, he has always been unwilling to go out. He simply takes the initiative to stay at home." In fact, Xiaoyan's mother is also very ambivalent. "After the amount of exercise is reduced, the child's appetite is also small, and the nutrition can't keep up with it, the physique will be worse, and the immunity will also become a problem. But it is really necessary to let him go out for exercise, and he is afraid that his body is not good yet. In case of going out for strenuous exercise, it is not suitable. Besides, it is also easy to get cold outside in the cold winter." After repeated entanglements, Xiaoyan's mother has to try to find an opportunity to let her son start downstairs, "I asked him to fetch water or take out garbage, or take him to the supermarket, so he could go out and move." As the parent of junior high school graduates, Xiaorui's mother was more worried. "The children have many online classes and homework, let alone go out for sports, and they don't even go out of their homes. After another winter vacation, after two or three months of 'home', their physical fitness will definitely decline significantly." The thought of having to prepare for the high school entrance examination after school began, Xiaorui's mother sighed repeatedly, "If you come up and run a long distance, your body will not be able to bear it. If you want to get a full score for 1000 meters, you have to challenge your physical limit. It is not a concept at all with normal jogging. But how long you can rest for training is different from the online statement. Some say 'Yang Kang' two weeks later, some say it will take longer, and we have no idea." The same worry is also Duoduo father. "The child doesn't love sports very much. He used to have physical education classes at school, but he can at least practice with him. Since he lived at home, he has been completely 'lying flat'. It's really hard to ask her to go out." The other day, Duoduo's father finally persuaded his daughter to go to the park with him, "I was going to take her jogging for a while, but I shouted tired before running too far, saying that her heart beat very fast. I saw her face was uncomfortable, and she was also very nervous, for fear of making another myocarditis, but if it went on like this, the physical fitness would only get worse and worse, and the body would be lying down." The problem is that there are risks in hasty training