Not all shin pain is a ‘shin splint’

Not all shin pain is a ‘shin splint’

Shin pain in athletes can be a bit confusing. Most of us just call any pain in the area ‘shin splints’, a reminder of days in track practice as teenagers. Coaches and trainers may even use this as a general catch-all term as well.

However, many times shin pain especially in adult runners is not ‘shin splints’ at all, but a much more annoying and important issue to resolve.

‘Shin splints’ as they are called by laymen, are micro-tears of the muscles on the outer shin. The thick muscle fibers here are stubborn and compact, and their location makes them hard if not impossible to stretch properly.

The important distinction here is that traditional ‘shin splints’ such as these are on the OUTER side of the bone in the actual muscle. Also called Anterior Compartment Syndrome, it is found only on the OUTSIDE of the shin bone.

In sharp contrast, pain in the INNER side of the shin is generally more related to the bone, as the inside of the shin is more osseous, not covered by thick muscle as the latter.

The muscles on the inner side are not actually inner shin muscles, they are in fact the muscles in the back of the leg that wrap into the inner bone where they insert there all along the inside of the tibia bone. This is the posterior compartment which most of us know as the ‘calf’ muscles, or more clinically, the gastrocnemius, underlying soleus, and all the muscles that flex the toes.

It is critically important to differentiate what side of the shin bone (tibia) the pain is on, whether OUTER or INNER.

Either of these two areas can have pain, either from doing too much too soon, changes in terrain, distance, sport, frequency of exercise, shoewear, etc. Walking, running and other weight bearing sports can also injure this area, not just running. However, running is the most predominant.

If pain on the OUTER side of the tibia can be attributed to muscular pain due to the majority of area being comprised of muscle, the INNER in sharp contrast displays signs of bone damage.

This bone damage exists on a continuum, as it depends how much damage has occurred and for how long. We can think of this in a circle or a cycle. At one end of the circle we have swelling and generalized bone inflammation just beginning to occur right at the juncture where the posterior calf muscles insert into the bone via the fascia (a fibrous go-between from the muscle to the bone). The tighter the pull of these muscles, the more their fascial connection to the bone is disrupted, causing pressure and pulling on the bone. The more pulling on the bone the more stress is placed on the bone itself.

Bone, like any other cells of the body, is constantly manufactured and constantly broken down. Just like your skin cells, they build up and break down and are readily replaced. But just like any other high traffic area, when there is too much stress or strain the bone growth and production may not equal bone loss. This is why we often see this phenomenon with runners, most specifically long distance or new runners, or runners who up their mileage more than the recommended 10 % a week. The bone growth often cannot keep up with the demand of the bone breaking (the running stress). The tighter the calf and posterior compartment, the quicker this equilibrium is damaged.

So if we look again at the beginning of our circle or cycle of INNER shin pain, the beginning stages are inflammation and some pain when the equilibrium is off. If we keep running, or doing whatever activity is causing discomfort, we move ahead in the circle and get more area of the tibia that is inflamed and stressed. Now the bone breakdown is exceeding our ability to put down new bone. We call this diagnostically Tibial Stress Syndrome. This may include multiple areas or the entire inside of the shin bone being tender to touch and painful with running, and we may begin to see some edema in the shin.

Along the circle from this, if the problem continues we will have a pre-stress fracture, which can eventually lead to a stress fracture.

We call it a circle or cycle and not a line progression because at any point we can stop doing weight-bearing exercise and give the bone growth a chance to surpass the bone breakdown and reverse the direction of the circle. It all just takes some rest to allow the bone to heal.

Yet time off isn’t always healing. Even after running cessation we may find when we get back to running the problem returns. This is why physical therapy is necessary. A physical therapist who understands these conditions will also work to take the tension off the posterior compartment so the stress on the bone is not able to return. There are also other ways we can teach you to take stress off this area, one of them being a thorough shoe evaluation. Your running shoe can an does play a major role in causing stress to the inner shin. Suggesting the right shoe can keep your toe flexors (the other posterior compartment muscles) from overworking and stressing the shin bone, and may also keep your arch properly supported depending on its structure. Other biomechanical corrections can also be made to keep this issue at bay. In addition, sometimes other factors are at play, such as bone density, vitamin D deficiencies and other medical issues we can help have addressed.

There is a big difference between INNER and OUTER shin pain. ‘Shin splints’ cause no major damage and the runner can keep running, as long as they don’t mind the annoyance. It’s just muscular. INNER shin pain, however, can be season ending. It’s better to nip it in the bud so the bone gets a chance to recover. Bone problems are not something we should run through.