Shin Splints is a condition resulting from the overuse of certain muscles in the shin. Both anterior and posterior shin splints exist: the anterior type involves the Tibialis anterior muscle within the anterior compartment, while the posterior type affects the Tibialis posterior muscle within the posterior compartment.
Before the causes of this condition can be understood, it’s important to first explore the function of each of the affected muscles. Both the anterior and posterior muscles are used to slow down pronation in the stance phase of gait: the tibialis anterior works first, followed by the Tibialis posterior. If a person over-pronates, or pronation occurs too rapidly, one or both of these muscles may have to work harder than usual. This causes fatigue to set in, resulting in inefficient force production. As a result, micro-tearing of soft tissue can occur, leading to an inflammatory response.
Because these muscles are wrapped in a fascial covering, the swelling caused by the tearing can become restricted. In addition to being very painful, this restriction can lead to a build-up of pressure that can ‘choke-off’ the blood supply to the muscles. In severe cases, this swelling causes damage to the deep peroneal nerve. Because this nerve supplies blood to the dorsiflexors in the foot, a permanent ‘foot drop’ can occur if it’s restricted for too long.
Shin splints are common in sedentary individuals who suddenly begin to run or walk long distances. If the individual also tends to over-pronate, the chances of injury are increased due to the combination of weak muscles from lack of activity. The type of shoe worn can also increase pronation of the subtalar and transverse tarsal joints, leading to painful tissue injury.
After receiving a diagnosis of shin splints, it’s crucial to immediately cease the activity that caused the damage. The injured area should be rested and iced in an attempt to control inflammation. Anti-inflammatories may also be beneficial. In severe cases, ultrasound and interferential therapy are recommended, allowing the full extent of the injury to be determined.
When the initial inflammation has died down, the patient can then be started on a gentle stretching program, gradually building up to a program that strengthens the affected muscles. Short distances can be walked, as long as the injury isn’t worsened. This distance can be increased gradually until no pain is experienced. At this point in recovery, foot orthotics may be introduced to correct the over-pronation. Without these, the condition is likely to re-occur, as the pronation will need to be controlled. After suitable orthotics have been obtained, the patient can begin running short distances. Other effective treatments include wearing the correct footwear, mobilising and manipulating the muscles, and adopting a gentle exercise and stretching program.