On our little trip last week I was able to read “Tread Lightly”, a book that came out last year that is a bit of an update on “what has happened since Born To Run came out.” I was a little discouraged initially when they opened with basically a rehash of “those amazing Africans who can run down gazelles” tale from Born To Run that – admittedly – is a pretty amazing thing. But then the authors (one of them was a high school runner who stopped in college and then rediscovered running at the ripe old age of 30 after he was horrified by a photo he saw of himself and realized he was overweight, and his co-author is a 50ish guy who was a former triathlete who got out of it and then re-discovered running as well as a cathartic endeavor) used that as a platform to go into more depth than BTR did on injuries (why they happen and why they haven’t decreased), a more-thorough history of the modern running shoe, a more-thorough analysis of running barefoot, the rise (and fall) of the concept of motion control shoes, fascinating sections on foot strike and stride length, and also - interestingly enough – finished with a chapter on nutrition.
Overall I felt fairly validated that my own opinions that were generally created by observation and anecdotal “evidence” were generally reflected by these guys, who had done WAY more research. It was pretty clear that both of them have been a bit “saved” by the modern, minimal running movement, but it was also clear that they were trying very hard to be objective, and referred to a lot of studies to back up their theories.
With regards to the evolution of the running shoe, it’s of course the stuff of legend that Bill Bowerman made the original waffle soles with his wife’s waffle iron blah blah blah. Slightly lesser-known is that he was also the protagonist of the elevated heel. His theory was that tipping the skeleton ever-so-slightly forward would actually propel runners forward at a better clip. At the time he was working with Onitsuka Tiger (the future Asics) before he and Phil Knight started Nike, and he was disappointed that they only acquiesced by 3/8 of an inch, instead of his desired ½ inch (he also is credited with using nylon as an upper material for his steeplechasers, since nylon doesn’t hold water the way that the leather shoes of the era did, not to mention being much lighter when dry as well). The facts that Bowerman wrote a wildly popular book called “Jogging” and the US team enjoyed good success under his tutelage at the 1972 Munich Olympics - where Frank Shorter won the marathon - further entrenched the power that Bowerman’s perspective held.
The authors’ perspective on the evolution of the “motion control” movement was that there was a general perception that runners pronate and runners get sore knees, so therefore shoes needed to control this movement. They reference the military study that I had heard about that measured arch height and arch flexibility, and also analyzed the long-held association of the “wet test”; that is, your wet footprint – flat, normal, or obviously high-arched – with shoe style selection. And they had found some other, more recent studies that put motion-control shoes on a variety of those who “needed” them and those who didn’t. These studies proved pretty conclusively that a) arch height as indicated by the wet footprint test has relevance to how much support one needs, b) medial posting – the most common method of limiting the pronation movement - doesn’t actually work, since our legs/body overcome that slightly-denser foam anyway, and c) those people who did pronate actually got worse with motion control shoes! “Every runner in the highly pronated group who were supposed to be wearing a motion control shoe got injured. In fact, highly pronated runners actually fared better in neutral-cushioned shoes.” In 2011, a study was published in a British journal of medicine that concluded:
The findings of this study suggest that our current approach of prescribing in-shoe pronation control systems on the basis of foot type is overly simplistic and potentially injurious.
Interestingly, one of the co-authors of this study was Gordon Valiant, who is an old friend of mine and has been doing basic research at the Nike Sports Research Lab for eons (and, not only did Gordon run a sub-2:00 half mile at something like 45 years old is one of the biggest forefoot strikers I’ve ever seen!). To be fair to the giants, good on Nike for allowing Gordon to be published like this…..
So why did it take 40 more years of before people started questioning the concept of an elevated heel and anti-pronation efforts despite the fact that many of the major shoe companies employed/engaged biomechanists and there was never any actual information that either of these things actually helped at all? The authors point a lot of blame at shoe stores that were using oversimplified metrics (“the wet test”, watching people run from behind) yet were eager to sell people shoes, but having been in the biz for a while, I think it’s a bit more complex than that. It’s a bit of a circular cycle:
I show magazines as being at the center of the problem, which is not necessarily the case; they don't have that much power. I think it’s more that they have a small effect on all the participants in the cycle who have little incentive to make dramatic changes.
I must say that I think it’s quite hilarious that despite 30-40 years of shoe companies trying desperately to one-up each other with their patented Flubber technologies it was a shoe sole company (Vibram) that introduces a product (Five Fingers) that changes their industry, and that product wasn’t even intended to be a running shoe in the first place! Though this actually takes a bit of credit away from other companies like Newton, Hoka, Inov8, Vivo, etc that were being developed at the same time, and as mentioned earlier, Nike helped a lot with the Free.
The book's section on stride length and footfall was quite provocative. Basically, they indicated that most people – especially at the slower, more recreational level – overstride, which inherently creates a toes-to-the-sky, heel-first strike that is then supported by a thick, cushioned shoe heel (and is more taxing on the system, which may account for the fact that the average marathon times have gotten slower and slower over the years). And what barefoot or minimal running effectively forces you to do is shorten/quicken your stride, but the truth is that you don’t need barefoot/minimal shoes to do this; you can just do it. I’ve been experimenting a bit on this with both running and skinning on skis (after the brilliant Colin Gregerson told me in no uncertain terms that longer skinning strides are an absolutely less-efficient way to go uphill faster) and find it pretty effective. And they pointed out that running faster – shorter intervals, fartleks, etc – is a great way to “pull” people into better, less-overstridy form in addition to increasing cardiovascular capabilities (as I love to say: if you wanna run faster, just run faster”).
And finally, nutrition. They pointed out that “Boston Billy” Rogers did the entire running world a bit of a disservice by winning consecutive Boston and NY marathons in the late 70’s while espousing a diet of ice cream and mayonnaise-laden pizza, and that people have this opinion that “if I run, I can eat a LOT”. Which means that a lot of recreational runners don’t necessarily see the pounds melt off/stay off the way they “should”, and that even as people are trying to shave ounces off their shoes, they may be allowing weight on their body to add – according to some studies – 2.5 seconds per mile for each extra pound on the body (over the “ideal” weight). And extra weight changes the way the body is carried in the running motion, and change can manifest itself in injuries. And the modern trend of sugary energy burst “food” products reinforces eating more - and not as nutritious – calories in general. They advocate “turning back the clock on nutrition” (the name of the chapter) and reference Michael Pollan’s “Eat Real Food. Not Too Much. Mostly Plants” quote as a good summary that a diet of whole foods, fruits, veggies, etc can help manifest more injury-free running. An interesting way to wrap up a book that’s ostensibly about legs, feet, and shoes.
If you’re a running geek or a shoe geek, it’s a great read, and if you’re only mildly interested it’s still a pretty good book.