Because these people do not exercise for a long time, the strength of bones and joints, muscle strength and endurance are very weak, and the physical hardware conditions do not allow long-term fitness activities. It is enough for junior trainers to control the training time to about 30 minutes, and the training frequency is three times a week. If the training time is too long or the training frequency is too frequent, the training intensity may exceed the maximum bearing capacity of the body and it is easy to get injured.