What Are Shin Splints?

Shin splints are one of the most common injuries amongst runners, especially novices. It’s also one of the most misunderstood and misdiagnosed injuries. Here, leading podiatrist Peter Feain tells us all about them.

Shin splints is actually a very general term that covers a variety of different injuries that cause pain in the lower leg. So the term shin splints does not give a very definitive diagnosis and without a correct diagnosis the ideal treatment strategy cannot be implemented. So if you are experiencing pain in the lower leg it’s important you see an experienced health practitioner and get it diagnosed as soon as possible. Below are some of the specific injuries to the lower leg that could be causing you pain.

Stress Fractures:

These can occur in any bone in the body and come about due to excess force going through the bone, which leads to small cracks. This excess force in running comes about obviously due to repetitive ground reaction forces from each foot strike. The body should however be able to handle these forces without breaking down, so if you are getting stress fractures it is usually from poor footwear leading to inadequate shock absorption, increasing the volume of your weekly mileage too rapidly, increasing the intensity of your running too rapidly, suddenly changing the surfaces you run on (going from cross country season to track season), poor running biomechanics and inadequate recovery, whether that be just from training loads or from training loads combined with external stressors such as work, family and relationships. With ‘shin splints’ the main bone that will develop stress fractures is the Tibia, which is the larger of the two bones in the lower leg. Pain usually increases gradually over a few weeks as more weight bearing activity is performed and there is usually a specific point where the pain originates from. It is imperative that you give this injury complete rest – anywhere from 4-8 weeks, even more if there are other complicating factors (anorexia, osteopenia or osteoporosis). Once you are fully rested and the bone is healed you need to assess with your health practitioner why the stress fracture came about and rectify your training, footwear, biomechanics etc to ensure it doesn’t occur again.

Medial tibial stress syndrome (MTSS):

This is pain along the medial aspect of the tibia usually along the distal two-thirds of the lower leg. It can initially present very similar to a stress fracture, so it’s important that a stress fracture is ruled out. Pain usually decreases during the warm up but then returns after running and is worse the next day. The pathophysiology of this injury is still not entirely understood. It was initially thought the pathomechanics was microtrauma to the periosteum and fascial attachments along the tibia from traction forces from the soleus and flexor digitorum longus. It is now thought that MTSS is a bone stress reaction caused by tibial repetitive bending forces. The main factors attributing to this injury are again the common training errors of increasing mileage and intensity too quickly, tight triceps surae, poor footwear, training on uneven surfaces, poor biomechanics and bad nutritional habits. Return to running is often much quicker than stress fractures with time frames of 3-6 weeks. This return to running should be slow and steady and asymptomatic. If symptoms do return, it’s two weeks rest then build back into it slower (being sure that all possible training and biomechanical factors have been addressed).

Chronic exertional compartment syndrome:

Within the lower leg there are 4 different segments where the muscles are surrounded by fascia to form separate compartments – anterior (tibialis anterior, extensor halluces longus, extensor digitorum longus & peroneus tertius), lateral compartment (peroneus longus, peroneus brevis), deep posterior compartment (tibialis posterior, flexor halluces longus, flexor digitorum longus, popliteus) and the superficial posterior compartment (gastrocnemius, soleus).  Compartment syndrome is pain which can occur in any of these compartments from an increase in pressure causing decreased blood flow & reduced tissue perfusion leading to ischaemic pain. It can be acute, which is a medical emergency and requires surgery, or it can be chronic, which can often be managed conservatively. Pain is usually a tightness and burning sensation, often with tingling or pins and needles in the leg or foot. Pain increases with running and decreases with rest. Conservative treatment involves decreasing running volume, ceasing any lower body weight training and ceasing any cycling. Deep tissue massage, dry needling and orthoses may help. When conservative measures fail a fasciectomy may be needed, which is where there is an incision in the fascia to decrease the compartmental pressure. If surgery was needed the return to full running is approximately 8 weeks. Again the return to running needs to be gradual and individualised.

Tibialis posterior tendonitis:

The tibialis posterior is an important muscle of the lower leg that acts to plantarflex, invert and control pronation of the foot. It originates at the posterior surface of the tibia and fibula and descends down the leg, running just underneath the medial malleolus to attach under the foot with the main portion attaching to the navicular. Pain usually arises around the medial ankle, just below the malleolus and extends towards the insertions. Pain can also extend up the tibia and can be sore on palpation. Tibialis posterior tendonitis is an overuse injury that is brought about by excessive pronation at the subtalar joint, meaning when the foot hits the ground it is unable to control the pronation of the ankle and midfoot as well as then being unable to resupinate the foot at toe off. The tendon is basically working too hard to control the motion of the foot. In older populations and diabetics this condition can progress to a complete dysfunction of the tendon and a flattening of the arch, which requires surgery. However tibialis posterior tendonitis in healthy populations does respond well to treatment, such as taping and orthoses to offload the tendon, appropriate shoes, flexibility and strengthening training and ensuring training is following the progressive overload principle.

So as you can see the term shin splints is a very open diagnosis with the above injuries being just the most common that occur in the lower leg. As with any injury the sooner you begin treatment the faster the recovery will be. However, this is dependant on an accurate diagnosis from the start. So rather than use Dr. Google, get yourself to a sports doctor, physiotherapist or podiatrist to assess you. Get the right diagnosis, and just as important, find out the reason why the injury occurred in the first place!