The common causes of lower limb soreness are lower limb muscle strain and severe osteoarthritis of the knee joint, as follows: First, lower limb muscle strain: prolonged standing work or excessive weight bearing can cause significant strain on the lower limb muscles. The continued increase in acidic metabolites in the muscles can cause adverse nerve stimulation, which can lead to soreness and swelling in the lower limbs, accompanied by weakness in the lower limbs. Second, severe osteoarthritis of the knee joint: severe osteoarthritis of the knee joint will lead to secondary atrophy of the knee muscles, and the patient’s usual walking distance and walking time will be significantly reduced, so that the soreness and swelling of the lower extremities will occur when bearing weight, accompanied by shaking of the lower extremities, and the patient usually cannot walk or stand for a long time. These diseases can be confirmed by X-ray and physical examination, and early treatment can bring about rapid relief of clinical symptoms. The leg muscles should be strengthened to avoid overexertion, and the knee joint should be protected to prevent severe osteoarthritis from occurring.