Pain in the shin is a common complaint amongst athletes and in particular distance runners. The term “shin splints” has been used to describe pain in this region, but it is somewhat misleading as it does not accurately describe the problem at hand and there are many different types of shin pain. It is common for shin pain to be the result of two or three separate pathologies occurring simultaneously. Medial tibial stress syndrome is where inflammation develops at the insertion of muscles (tibialis posterior and soleus) to the inside edge of the tibia in the lower leg, a diagnosis traditionally referred to as “shin splints”. Stress fractures typically present as sharp and localised pain at a specific point along the shin bone. In severe cases immobilisation in a cast is required to give the bone a window of opportunity to repair. Compartment syndromes can cause pain on the front and outside of the shin and also in the calf. The muscles of the lower leg are organised into compartments enclosed by inelastic connective tissues. When we exercise our muscles, they can swell by up to 20% of their volume. If these tissues enclosing the compartment are tight, pressure within the compartment rises significantly putting pressure on nerves and blood vessels leading to symptoms including pain, burning sensations, pins and needles, and numbness. Pain on the outside of the shin can often be due to entrapment of the superficial peroneal nerve, or referred from the lumbar spine.
The calf muscles and Achilles tendon form our ‘propulsion system’ when walking and running and due to their design and their attachment to the heel are incredibly efficient in this action.
Injury to the calf muscles generally comes in the form of a tear or strain, often due to a sudden burst of acceleration, or a contusion resulting from direct trauma. Injury can also result from repetitive microtrauma to the muscles over longer periods of time, often as a result of various biomechanical issues.
Cramps are common in the calf region and can occur at rest or after exercise. They tend to occur in the more conditioned athletes and experience suggests that subtle nerve irritation in the region may be a factor in some cases.
The Achilles tendon is the thickest and strongest tendon in the body. Overuse injuries (tendinitis, tendinosis) are especially common in runner’s who are 30 times more likely to develop these problems than sedentary individuals. Traditionally tendon problems have been thought to be due to inflammation, but it is now well established that the pathology degenerative change within the tendon. Strengthening exercises to progressively load the tendon in a controlled way are effective in reversing this pathology.
Complete rupture of the Achilles tendon occurs predominantly in the 30-40 age group, patients often describe the feeling ‘as if being kicked in the back of the leg’.