Weakness and lack of strength in the legs may be caused by varicose veins of the lower extremities, lumbar disc herniation, peripheral neuropathy and other diseases. 1. Lower extremity varicose veins: the basic causes of this disease include congenital weakness of superficial veins, poor structure and function of lower extremity venous valves, leading to elevated pressure in lower extremity veins. It can be triggered by factors such as prolonged standing still and heavy physical activities. Most of the patients have no obvious discomfort in the early stage, but with the further development of the disease, there will be symptoms such as weakness and soreness of the legs. 2. Lumbar intervertebral disc herniation: the root cause of this disease is disc degeneration, followed by disc injury, heredity, lumbar spine developmental abnormality, etc. It is often triggered by factors such as acute trauma and prolonged work, resulting in a decrease in the muscle power of the lower limbs, which can be manifested as weakness and lack of strength in the legs. 3. Peripheral neuropathy: the etiology of this disease is more complex, may be related to genetics, nutrition and metabolism, poisoning, vasculitis, tumors, autoimmune diseases and other reasons. Some patients may have muscle weakness, muscle atrophy, uncoordinated limb movements and other symptoms, so the patient may have weakness and lack of strength in the legs. There are many reasons for the weakness and lack of strength in the legs, so patients should go to the hospital to improve the examination and clarify the cause of the disease.