As I continue to train for my first full marathon and develop many of the common symptoms and pains experienced by long distance runners, I find myself looking more and more towards my $150 running shoe, designed to stabilize my feet as I run, alongside my $500 custom built orthotics designed to prevent over-pronation.
With at least two in three runners sidelined because of lower extremity pain such as patellofemoral syndrome (runner’s knee), a hotly debated subject in recent years has been the proficiency of the athletic shoe. Marketed to prevent and treat such injuries are a wide array of choices such as motion control, stability, gel cushioning and arch support, however in recent years both kinesiologists and orthopaedic doctors have debated whether they actually prevent or cause injuries in the lower legs. A recent article published in the New York Times suggests orthotics are not only impossible to fit correctly, they can actually make the muscles work up to 50% harder. So mile after mile on my long Sunday run, I ask myself – do my running shoes and orthotics actually have an impact on my muscle effort and are they possibly causing my injuries?
I also ran across a fascinating TEDTalk by Christopher McDougall about the barefoot ultra-marathoning Tarahumara from Mexico, for whom running injuries are rare.
Fortunately, because of the work that I do, I was able to put this theory to the test. By using vibromyography (VMG) as an objective assessment of knee muscle balance, I designed an experiment that would test the differences (if any) in my footwear.
Single VMG sensors were attached to my vastus lateralis, biceps femoris and the sartorius muscles using an elastic strap. I then performed 6 one-legged squats with inward rotation of the knee while wearing inexpensive running shoes. The graph displays the averaged level of effort expended during the 6 repetitions. The red line represents the Sartorius; the blue the Vastus Lateralis.
I then repeated the exercises wearing motion control stability footwear:
and then a third time with orthotics in those expensive running shoes.
Lastly, I repeated the exercises while barefoot.
Upon completion of each set, the amplitude of effort generated simultaneously during the exercise by all three muscles was compared.
If the goal is to strive for muscle balance we can see from the experiment that both barefoot and running shoes with motion control and orthotics appear to deliver the best results. Notably, the muscle effort was least balanced with inexpensive running shoes and only slightly better when the motion control footwear without orthotics was worn. In addition, all shoe wearing results showed that the sartorius worked at least 40% harder than it did during the barefoot exercise.
So, in concurrence with claims by orthopaedic doctors and kinesiologists, vibromyography suggested to me that my footwear of choice doesn’t in fact control my motion nor does it correct my over-pronation (although notably it does not negatively impact it as has been suggested in other articles). There is, in fact, no difference, at least for me, between wearing my extremely expensive running shoes with my very expensive custom-built orthotics and going barefoot, despite the claims of the overly helpful sports store manager! Maybe the Tarahumara are on to something.