Legs are always weak, the common causes are the following: 1, the presence of chronic strain on the patient’s leg muscles, due to the patient’s prolonged high load of labor or physical exercise, resulting in injury and strain on the leg muscles. The presence of these pathological factors will affect the function of the muscles, resulting in the symptoms of leg weakness. 2, seen in systemic ionic disorders, such as low potassium, low calcium, due to ionic disorders, will lead to abnormalities in the working environment of the muscles, which will also affect the function of the muscles, resulting in the symptoms of corresponding muscle weakness. 3, seen in the lower limbs of the nerves are affected, such as lumbar diseases, resulting in the lower limbs 4, cervical spondylosis can also lead to symptoms of weakness in the lower limbs, cervical spondylosis is common in the spinal cord type of cervical spondylosis, there will be weakness in the lower limbs, unstable standing, walking with a feeling like stepping on cotton. 5, varicose veins in the lower limbs, vasculitis, etc. will affect the blood circulation in the lower limbs, which will also affect muscle function, resulting in symptoms of weakness. 6, certain neurological and psychiatric factors can also lead to symptoms of weakness, Certain neurological and mental factors can also lead to weakness of the lower limbs, such as prolonged mental stress, mental depression, etc., which can also lead to symptoms of limb weakness.