Patient: When I woke up in the morning for the past two days, my right leg was sore and weak. Both legs were different from usual when walking. After a few minutes, it returns to normal. What is the problem? Meng Zhe, Department of Pediatrics, Second Affiliated Hospital of Sun Yat-sen University: 1, infants and young children are in a fast-growing stage, common to “growing pains”, can be corrected by increasing nutrition and calcium supplements; 2, trauma can also cause the above situation, whether there is a history of trauma? 3, in addition to other diseases, need the doctor’s correct judgment. Have you received polio vaccine, i.e. “sugar pills”, have you had fever, cough, vomiting, limb weakness and other symptoms? The best way to determine the cause is to have a pediatrician check it out!