In no way do I consider myself an expert on foot biomechanics, or any biomechanics for that matter. Whenever I do read some technical study or text on the subject my eyes glaze over in about a minute. However, one of the most often asked questions I get concerns shoes and the use of orthotics.
I can't tell you how many injured recreational and competitive runners I see that wear orthotics, but who are 1. Weak 2. Have significant joint restrictions in the hips and ankles 3. Possess some tissue/muscle tightness or restrictions, and want to know how they can get rid of nagging pain or tightness and get back to running.
Hint: All of those issues are related.
What I do know about the subject from working with practitioners such as Lenny Parracino, Gray Cook, Bill Hartman, and reading work by Gary Gray, Thomas Myers and others is that what happens at the foot when we move affects much of the rest of our body, which is why this article in today's New York Times really struck a note.
Some key quotes:
Then what, Dr. Nigg asked in series of studies, do orthotics actually do?
They turn out to have little effect on kinematics — the actual movement of the skeleton during a run. But they can have large effects on muscles and joints, often making muscles work as much as 50 percent harder for the same movement and increasing stress on joints by a similar amount.
As for “corrective” orthotics, he says, they do not correct so much as lead to a reduction in muscle strength.
In fact, he adds, there is no need to “correct” a flat foot. All Jason needs to do is strengthen his foot and ankle muscles and then try running without orthotics.
Dr. Nigg says he always wondered what was wrong with having flat feet. Arches, he explains, are an evolutionary remnant, needed by primates that gripped trees with their feet.
“Since we don’t do that anymore, we don’t really need an arch,” he wrote in an e-mail. “Why would we? For landing — no need. For the stance phase — no need. For the takeoff phase — no need. Thus a flat foot is not something that is bad per se.”
Whoah - more stress on the joints and it makes you weaker. Sign me up huh?
There is a lot to digest there, but I'll preface that by saying according to very smart osteopaths, PTs, and podiatrists I have heard speak on the matter there is a time and place for orthotics.
However, those same practitioners seem to agree that if there is not an acute injury, defect, or some outstanding reason then as the quotes above state orthotics may do more harm than good.
I have fairly high arches, which would lead "experts" at a running store to prescribe supportive shoes, and probably inserts. However I wear nothing but minimalist footwear such as Nike Frees and have recently been test wearing some free/five finger-like prototypes from Adidas, and can say for certain my feet, knees, and back are stronger and feel better when I train or walk around in these shoes and worse when I wear crosstraining shoes with more arch support.
In addition, I have had thorough assessments and treatment done by Dr. Parracino, who specializes in mechanics and builds orthotics. Despite doing a comprehensive gait and movement analysis while barefoot he didn't see any foot related problem but traced my back issue back to a hip capsule matter.
That along with the aforementioned work by Gray Cook etc... leads me to believe some of what that article addresses may apply to our shoes.
And what are the typical crosstraining shoe if not a low grade orthotic? It provides artificial support to the arch, and will affect how the foot moves and thus alters how the joints, bones, muscles, and tissue in the ankles, legs, and hips receive and produce force.
In 2009 Univ. of Texas Basketball strength coach Todd Wright gave an interesting talk at the Perform Better Summit on foot biomechanics and told us about a top NBA prospect he was training that was having some severe back pain that was preventing him from playing. Todd had exhausted his ability to fix this kid, so had him assessed in person by Gary Gray, who after watching this player move promptly traced the problem back to one of his feet. Something in his foot/sub talar was altering his gait, which then increased the stress up the kinetic chain, causing compensation in his back to the point of dysfunction.
Instead of prescribing orthotics Dr. Gray had Todd train this kid barefoot in the gym and do a battery of corrective work designed to fix the faulty movement pattern. Todd said the kid's back was quickly back to normal and he went on to sign a fat NBA contract.
Todd now has many if not most all of his athletes train barefoot in the gym. Other smart coaches and trainers, such as Jon Hinds, also advocate minimalist footwear or going barefoot.
We should be cautious however in saying everyone should train a certain type of shoe or barefoot if there is reason to suspect a foot issue. However, it seems we are just seeing the tip of the iceberg when it comes to research on movement quality and shoes.
For more resources I highly recommend Gary Cook's book Movement and Thomas Meyer's Anatomy Trains.
For more detailed information on the foot and how it relates to joints up the chain check out this excerpt on the joint by joint approach from Gray Cook.