In reviewing this column’s past entries to find a topic that has never been covered, I discovered that – incredibly! – I’ve neglected one of the most common of all running injuries: shin splints! Hard to believe, since after runner’s knee and plantar fasciitis, shin splints are probably the most frequently heard complaint of runners – particularly beginners. (It was my first running injury when I ran track in high school!)
The term shin splints is another one of those “garbage can” diagnoses [see: Sciatica] that encompasses several distinct pathologies that cause pain somewhere in the leg between the knee and ankle. The site of pain is usually adjacent to the larger of the two bones in the leg, the tibia, which explains the alternative term now in vogue for this injury – tibial stress syndrome. Pain may be felt along the inner or outer border of the tibia, depending on the exact structure affected.
Shin splints, or TSS, have most often been associated with inflammation of the tendon of the Tibialis posterior muscle, which runs along the inside portion of the tibia. Recent studies have challenged this long-held belief in favor of another muscle, the soleus (part of the large calf muscle), that has a greater area of attachment on the tibia. It really is an academic question, however, as both muscles play a crucial role in controlling the amount and speed of pronation of the foot during the early stance phase of gait. It comes as no surprise then that those runners with a tendency to overpronate are the ones most often afflicted with TSS.
When pain is felt on the outer ridge of the tibia, the structure most likely injured is the Tibialis anterior, which controls the lowering of the foot to the ground after heel strike. Basically, it keeps your forefoot from “slapping” the ground when you first land, but this muscle also helps decelerate the pronation movement as well. Those who run steep downhills are especially prone to developing this form of tendinitis.
Some experts feel that shin splints really involves none of these tendons. They attribute the pain to inflammation of the periosteum, the thin, membranous tissue that covers the shaft of the bone. It is actually the periosteum, and not bone tissue directly, to which muscle tendons attach. The theory is that periostitis occurs when overuse of these muscles pulls this tissue away from the bone, causing inflammation, swelling, and sometimes tenderness right along the shaft of the tibia.
There is some evidence that periostitis may be a forerunner of stress fractures, so this is definitely something to be respected. Sharp, pin-point pain and tenderness – especially to percussion – at a specific site along the shaft of the tibia may be an indication of stress fracture and should be investigated carefully.
Whatever the actual structure affected, TSS generally presents with a consistent history and pattern. Novice runners seem to be most prone to developing shin splints, probably because the sudden stress on the tendons and bones is much greater than what they can tolerate. It’s a classic case of “too much, too soon.” As mentioned already, those with overpronation tendencies, even experienced runners, are also susceptible, though usually there is also a history of a sudden increase in distance or speedwork. Once the “disease” has been caught, the pain is usually felt right at the beginning of the run, subsides to some degree after the muscles have warmed, but is worse (throbbing!) soon after the run is completed.
Should you find yourself experiencing this problem, your best bet is to cease and desist running completely until the area is no longer tender to touch and completely non-painful with walking. This can be a matter of days or weeks, depending on how long you persisted in trying to run through the pain before listening to that piece of advice. You can help the healing process with anti-inflammation medications (aspirin, ibuprofen) and ice massage. You can also keep in some shape with biking or swimming – both safe alternatives for this injury. When you do start running again, work back into it very gradually. If the problem returns, it may be time for a professional evaluation to determine if the problem is a biomechanical one.
