Shin splints are a condition where there is pain in the anterior tibia caused by overuse of the legs. They are most common in inexperienced runners who overtrain, but anyone engaging in running or other high-impact sports may experience them. The pain is typically in the upper, anterior tibia and is worsened by exertion. There may be slight tenderness of the affected region.

Shin splints result from the anterior leg muscles being stressed by running, especially on hard surfaces or extensively on the toes or by sports that involve jumping. Insufficient padding in the shoes is a contributing factor. Over-pronated and/or flat feet can lead to increased stress on the lower leg muscles during exercise, and people with high arched feet can also experience shin splint discomfort because this foot type is a poor shock absorber.

The treatment for shin splints is rest. Running and other strenuous lower limb activities should be avoided until the pain subsides and is no longer elicited by activity. In conjunction with rest, anti-inflammatory treatments such as icing and drugs such as NSAIDs may be suggested by a doctor or trainer, though there is some controversy over their effectiveness. A contributing cause of shin splints in some cases is the relative weakness of the muscles on the anterior of the lower leg compared to those in the calf. In this case exercises that preferentially strengthen the anterior muscles may help alleviate or avoid shin splints.

If the shin splints are ignored and the individual continues running, over a long period of time, he or she is at increased risk of stress fractures at the site of the previous shin splints. Runners who continue running with shin splints may experience a tingling feeling in the toes or feet.

The term shin splints is not a medical diagnosis, but a colloquial, and quite common term for a number of separate conditions. A bone scan may be useful to confirm the diagnosis.

Shin splints are also contributed by old shoes that no longer provide enough cushioning. Runners are advised to replace shoes after they have run about 400 miles or less in a pair. Some shoes may be less durable and need to be replaced sooner.

The term "Periostitis", referring to the inflammation of the periosteum, is sometimes used as a synonym for shin splints.