Shin splints, though a commonly used term, is not a clinically defined medical diagnosis 1. The term generally refers to pain that occurs in the shins. The shin bone is known as the tibia, and is the second largest bone in the body, after the femur in the upper leg. The main symptom of shin splints is pain which can occur is several places, including the inside of the tibia, or the medial tibia; or along the outside of the tibia, or the lateral tibia 1.

Pain

The primary symptom of lateral tibial shin splints is pain along the outside edge of the tibia 1. The pain can occur anywhere along the length of the tibia, from the top near the knee to the bottom of the bone near the ankle, although shin splints most commonly occur in the lower part of the leg, according to Rice University's SportsMedWeb 12. The pain is usually caused by inflammation of the tendons, muscles or fascia, the thin layer of tissue that covers the tibia, explains MedlinePlus 1.

Increase in Pain

Shin splints occur most often in runners, reports the National Institute of Arthritis and Muscoloskeletal and Skin Diseases 13. The pain often first develops when a person begins a new exercise routine or increases the intensity of his routine. Many runners report that the pain starts at the beginning of the run, then disappears after awhile, only to return after the run stops, sometimes the next day, notes SportsMedWeb. Beginning other types of activities, such as military training or aerobic dancing, may also trigger shin splints, according to MedlinePlus 1.

Risk Factors

Certain factors or behaviors can increase the risk of shin splints 1. A common cause of lateral tibial shin splints is over-training, particularly not leaving enough recovery time between workouts, explains the National Institute of Arthritis and Muscoloskeletal and Skin Diseases 13. Improperly warming up or stretching can lead to irritation of the muscles or tendons in the lower legs, as can an improper running technique. Running on hard surfaces also increases the risk of shin splints 1. Runners with a very flat arch in the foot, also known as an overpronated arch, tend to develop shin splints more often 1. Running shoes that do not have enough arch support further increase the risk of shin splints 1.