Shin splints may be caused by ischemia (decrease in blood supply) to the shin, tiny tears in the muscles or from the partial tearing away (avulsion) of the muscles from the periosteum (membrane covering the bone) of the tibia (shinbone). This may be due to a number of factors.

Overdoing athletic activities commonly results in shin splints. In most cases, this means exercising or training too hard, too fast or for too long. Suddenly increasing intensity or duration of exercise, particularly running, contributes greatly to the development of shin splints. Running on slanted surfaces, such as up or down hills, can contribute to shin splints.

Foot problems may increase the risk of shin splints. Flat feet (pes planus) may roll too far inward (overpronate) when running, increasing impact and stress on the shins. However, abnormally high arches may also contribute. Many of these foot problems can be corrected with proper footwear or special inserts (orthotics). A tight Achilles tendon, which stretching exercises can ease, may also be a factor. Likewise, the wrong kind of footwear (e.g., walking shoes for running, running shoes for walking), worn-out footwear or improperly fitting footwear may lead to shin splints.