Sore and weak walking legs may be caused by leg fatigue, anemia, hypokalemia and knee arthritis. 1. Leg fatigue: mostly seen in long-distance walking, running, etc., the leg muscles carry out anaerobic respiration, forming too much lactic acid accumulating in the muscles, and the patient may have leg pain, weakness and weakness, which usually improves after resting. 2. Anemia: patients may have pale skin, panic, loss of appetite and other symptoms, and when it involves the neuromuscular system, it may be manifested as walking leg pain and weakness. 3. Hypokalemia: usually caused by insufficient intake or excessive loss of potassium, patients may show symptoms such as weakness of limbs and legs, slowing down of intestinal peristalsis and decreased tendon reflexes. 4. Knee osteoarthritis: If patients suffer from knee osteoarthritis as well as muscle tissue damage and other factors, it will also cause walking leg soreness and weakness. In addition, cerebral insufficiency of blood supply, high blood pressure, cervical spondylosis, etc. can also lead to the symptoms of walking leg weakness, it is recommended that patients go to the hospital in a timely manner, under the guidance of the doctor to clarify the cause and reasonable treatment.