There is a disease where the symptom is that a child’s legs are too weak to go up the steps, and then he won’t be able to walk anymore. What is it?

This is generally a symptom of some muscle weakness. If it focuses on the legs, it is called the phenomenon of poliomyelitis. It is also called the state of poliomyelitis. This allows for symptomatic examination and treatment. This requires vaccination and sugar pills to be pre-coupled, and a certain effect can be achieved, so you can go for examination early and get injections and medicines on time.