Slight soreness in the knee after running, but no pain.

Knee soreness without pain after running may be caused by lack of exercise, meniscus injury, synovitis, and other conditions. Specific analyses are as follows:

1. Lack of Exercise

After prolonged running, muscles and bones can easily become fatigued, leading to lactic acid buildup in the knee area, resulting in aching sensations and discomfort. This is especially common among beginners who are still in an adjustment period, during which muscles and ligaments have not yet adapted to the load and intensity of running. Applying a warm towel for local heat therapy can promote blood circulation and help gradually relieve symptoms.

2. Meniscus Injury

If movements during exercise are too intense or if one runs frequently without proper knee protection, cartilage wear may occur, potentially causing muscle strain and meniscus damage in the knee, leading to localized feelings of soreness and swelling. An arthroscopic examination is needed to assess the condition accurately. Medications that promote blood circulation and unblock meridians may help alleviate symptoms. In more severe cases, medications such as glucosamine and chondroitin sulfate may be taken under medical guidance to improve the condition.

3. Synovitis

When inflammation affects the knee joint, it can trigger aseptic inflammation within the joint. This aseptic inflammation may increase joint fluid production or elevate secretion of local aseptic inflammatory factors, which in turn cause protective symptoms such as knee soreness and weakness. For faster relief, medications such as loxoprofen sodium tablets or ibuprofen tablets may be used.

In addition, similar symptoms could also result from osteoarthritis, patellar chondromalacia, rheumatoid arthritis, and other conditions. Patients experiencing severe symptoms should promptly seek medical attention at a hospital and receive appropriate treatment.