Not so long ago, when a runner experienced pain below the knee, this was termed "shin splints". Today the term applies to one (curable) condition known as "medial tibial stress syndrome"(MTSS). This overuse injury is second to "runners knee" with regards frequency of occurrence in runners.

In this condition shin pain is caused by bone stress at the inside (medial) edge of the tibia (shin) bone. MTSS is not caused by increased pressure in the muscles of the lower leg.

There are two categories of causes:

1) Training errors: Too much, too soon is the most common reason for many overuse injuries in runners. This applies to novice runners, and those training for a big event like a marathon. It is thought that the lower leg bones (tibia & fibula) are not strong enough to withstand the stresses, and do not have enough time to adapt to the increased workload.

• Overstriding causes the forefoot to slap on the ground. This occurs especially when running downhill. Muscles in the lower leg overwork to control the forefoot, and cause stress where they attach to the tibia.
• Excessive pronation is thought to cause stress in the tibia in two ways- through repetitive torsion (twisting) of the bone during foot strike, and through overworking of calf muscles that control pronation while running.

Initially one may be able to run through the pain. If ignored the pain can interfere with training later on. The extreme situation occurs when the runner ignores the pain, and goes on to develop a stress fracture of the lower leg (tibia).

Treatment depends on the causes. An alteration of one’s training programme may be needed along with correction of faulty biomechanics. Pronation is a normal phenomenon, but this may need to be controlled to minimise stresses through the tibia and fibula while running. Appropriate running shoes, and/or prescription of orthotics may be needed.

A stress fracture is a far more serious injury, and one usually requires investigations such as a bone scan to diagnose this. In order for a stress fracture to heal, one needs about two months of rest from running! Inadequate rest can lead to ongoing leg pain, and a lengthy delay before one is able to run without pain.

Happy running!

Jonathan King