The causes of weakness in the legs and feet of the elderly include: 1. Calcium deficiency leading to osteoporosis. 2. Central nervous system lesions, such as cerebral infarction, cerebral hemorrhage, TIA, spinal cord lesions, etc.. Cerebrovascular lesions cause weakness in one lower limb, while spinal cord lesions cause weakness in both legs and feet, and in severe cases there may be paraplegic planes. 3, Parkinson’s disease, Parkinson’s disease is most often seen in the elderly, often one lower limb is sore and weak, gradually developing to the ipsilateral upper limb and the opposite limb. 4, electrolyte disorders, such as hypokalemia, hyponatremia, etc. 5, peripheral neuropathy, such as diabetic neuropathy, chronic Green-Barre syndrome, mostly manifesting as symmetrical weakness of both lower limbs. 6, lumbar spinal stenosis. 7, infectious febrile diseases, such as viral infections, pulmonary infections, etc. Patients often present with weakness of the limbs, which may be accompanied by nasal congestion, runny nose, cough and sputum, etc. 8, myasthenia gravis that occurs with increasing age. Therefore, elderly people with sore and weak legs and feet should go to the hospital promptly for treatment to clarify the cause.