Simplifying why a foot orthotic does not reduce shock when running.
All too often I have patients (especially runners!!) present to my office with foot or leg pain and bags of shoes and orthotics which are not helping. Why? I went through the this discussion with several patients this week, so I figured why not share it on my blog. Also, what many reading should understand is that my explanation is based on experience of treating both runners as well as the general population and understanding what works and what doesn’t. The peer reviewed literature in both Orthopedic and Podiatric medicine are not clear as to the scientific or proven outcomes of treating the “common” everyday running injuries with orthotics. Do they work? Sometimes. Why? It’s not scientifically proven but the answer to me is simple- they’re indirectly changing someone’s gait. While you may think that it’s resolving your back pain by “aligning” your back, it’s probably not that scientific.
Many of my colleagues, especially the status quo, and those who have failed to keep up with the current trends and patterns in the running arena, are still stuck in the modern era of prescribing an insert to “fix” problems. Even those who focus on shoes are not addressing the issue. Many are still stuck in the era of fitting shoes based on foot type. This paradigm is outdated and proven ineffective. Here’s a simplified example of why using an orthotic to “control” motion is the right answer.
Let’s use the example of a simple spring. The more coils available in the spring, the more shock it will absorb.
Now let’s compare that to our leg using three joints- the ankle, the knee, an the hip. Three coils. If you land on the midfoot or forefoot region (which is where you should be striking) you will engage the muscles whose tendons cross the ankle joint, knee and hip when landing. If you land on your heel (heel striking) you will no be absorbing shock or decelerate motion at the ankle. In essence, your losing 33% of the shock absorbing potential by not engaging the lower extremity muscles which control the foot.
The posterior tibial tendon is a commonly discussed tendon which crosses the ankle joint and controls the inversion and eversion movements of the heel bone (and other joints), or subtalar joint motion.
It prevents the inward collapse of the heel and is one component of pronation control. Notice, that I said ONE. Pronation involves several motions of the foot and subtalar joint so we should not only focus on the posterior tibial tendon in terms of “controlling” pronation. In fact, pronation is a GOOD thing. It absorbs shock.
The idea of using an orthotic is that it will “control” or stop the eversion of the subtalar joint. This is all based on heel striking. Consider that if you do not heel strike, and land on the midfoot or forefoot area (same thing unless you’re “on your toes” – which is also bad!) you will engage over 5 more muscles and tendons to absorb shock or reduce the stress to the posterior tibial tendon. By simply changing your foot strike pattern, you will improve your shock absorption potential through engaging more muscles which are really not being used when you heel strike.
In summary, instead of trying fix those “shinsplints” by wearing an orthotic, alter your running by landing on your midfoot and making your foot work the way it was intended to work. Remember, you need to rest and heal any stressed area or “overuse” syndrome that you are dealing first before transitioning to a midfoot strike pattern. Transition gradually as you will be waking up muscles that haven’t been used in years!
Really good article, Dr. Nick. Especially he comparison with the spring helps me to understand the importance of using the ankle joint while running. But whenever I try to switch to mid foot strike for a short portion of my track I still have more pain than only running on heel strike, though. And it is even worse when I try this on barefoot shoes on short tracks. So I think the ramp up phase must be really really slow (over months rather than weeks) so that the muscles and tendons can accommodate slowly – I my case at least. Is there other training useful (e.g. some kind of strength or stretching training) which can support the transition process a bit? Or is just learning by running the only method that helps?