Generalized weakness and legs feeling unable to walk may be caused by the lack of trace elements potassium ion, degenerative knee joints, cerebral infarction and so on. 1. Lack of trace element potassium ion: potassium ion and hyperthyroidism, infection, exertion and other factors are closely related. If the body lacks trace element potassium ion, causing hypokalemic paralysis, which can lead to generalized weakness and legs feeling unable to walk. 2. Knee joint degenerative disease: it may be older, muscle atrophy gradually. When it is serious, it will also be manifested as generalized weakness of legs and feeling of not being able to walk. 3. Cerebral infarction: If the blood vessels in the brain are blocked, they cannot provide blood to the nerve cells normally, which affects the transmission of signals and manifests symptoms such as numbness and weakness of the limbs. In addition to the above diseases, other diseases such as stroke, lumbar degenerative disease, trauma to the legs, etc. can also appear generalized weakness of the legs feel unable to walk, should be timely medical examination, according to the cause of the corresponding treatment methods.