Shin Splints

QUERY:

A reader and marathon clinic participant writes, “Hey Doc, last year when I joined the Honolulu Marathon Clinic, I developed shin splints.  Fortunately they went away and I completed my first marathon.   Now I’m beginning to run again and I don’t want them back.

RESPONSE:

This is a good news bad news situation.  The good news is shin splints are usually a “first year” phenomenon and when individuals train properly, shin splints rarely return in the second year of training. 

 

CAVEAT:

Unless of course that individual becomes over enthused or suddenly increases to prodigious mileage and/or speed.   On the other hand because shin splints develop in the first year of training and as noted are a sign of overuse, while the probability of return is small, it is not negated.  

ETIOLOGY:

Exactly what are shin splints?  Shin splints represent the result of the body trying to remodel itself to a new task.  And yes, the body is capable of making tremendous adaptions depending on the various workloads that are imposed.  One only as to look at the habitus of the long-distance runner versus the sprinter or weightlifter to realize how much body remodeling can occur in response to a challenge. 

The lower legs are no different.  The anterior flexor compartment muscles (those on the front) obtain their support by attaching to the fascia on the anterior surface of the tibia (shin).

To get a better picture, when visiting the supermarket, look at ribs, particularly lean one’s (vegetarians you can do this too because you’re only looking).  You will note that the intercostal muscles (the muscles between the ribs) attach along the entire length of the rib in a fibrous latticed fashion in order to facilitate breathing.  The lower leg muscles attach to the shin in the same fashion.  When these muscles are introduced to a new activity, such as recreational long-distance running with its repetitive 5000 stop steps an hour, an attempt is made to reconstruct to this new activity. 

Shin splints are results of the terrible 2s.    i.e. 2 much, 2 soon, 2 often and 2 fast which then becomes “2 bad 4 me’. 

Generally shin splints progress in intervals of several weeks from initial pain (indicating the fiber is beginning to stretch) to tenderness to touch, to induration and swelling (a depression occurring over the tender area of the shin if one applies pressure) and then finally death or tear of tissue.   But just as a broken bone is always stronger after the fracture has healed (with its protective callus as seen on x-ray), the muscle (if it survives) likewise become stronger and not weakened by this process. 

In advanced shin splints, if one did an MRI or similar sophisticated investigative technique, one would note that the fibers along the shin are actually tearing off and reattaching up and down the shin remodeling in order to better facilitate running style.  In essence then, the shin splint is the beginning of a fatigue fracture and indeed it can progress to that.

TREATMENT:

Clearly because the shin splints did not exist before your running program, if running had not occurred, they would not have appeared. The treatment is simple.  The body is telling the individual that too much is occurring too soon and to back off.

The bottom line is that when symptoms appear, one needs to learn to back off by either running slower or less frequently.  Additionally, ice helps decrease the inflammation whereas heat and massage make it worse.  Anti-inflammatories such as nonsteroidals, (ibuprofen, Motrin, etc.,) are helpful, but if one uses them to cover the injury (by hiding inflammation and pain) training when the injury resurfaces, it will be worse than before.   Therefore, use nonsteroidals only when you are not running; do not take them on the days prior to your run.

Shin splints can take as long as 6 to 8 weeks to heal and if one fails to make progress, one should contact a sports minded physician knowledgeable in this area.  A major stress fracture resulting from shin splints might require casting, which virtually predicates that that leg may never be as strong again as it was before, something to assiduously avoid. 

When starting over again, do your running more slowly, less often and once you can run very slowly for a month at 1 hour 3 times per week (20% slower than your former training base), return to your former running schedule.