Although there is no strict age limit for strength training, from the point of view of health and training effect, strength training should be carried out at a suitable age. There is a weightlifter named NS in Bulgaria. He set his first adult world record at the age of 15. 16 years old, NS weighing 56 kg can clean and jerk 170 kg. However, the training of this little weightlifting genius has been controversial. Many people think that premature high-intensity strength training may have some adverse effects on teenagers' anatomy, physiology and mood. The American Orthopedic Association, Sports Medicine Association, American Pediatric Association, American Sports Medicine Association and other organizations have formulated the basic outline of children's resistance training. They think that children before the age of 7 should not be trained in resistance, and they can engage in mild resistance exercise at the age of 7, and then gradually increase the training intensity. From the age of 16, they can try an entry-level adult training program. What is the effect of resistance training for younger children? It is found that children's resistance training is very effective in strength growth. However, before puberty, the increase of strength is not accompanied by obvious changes in muscle size. But human muscle strength can only reach its peak when women are 20 years old and men are 20-30 years old. Children's neurological function is not fully developed, and even after training, it is generally impossible to reach the maximum strength.