My pseudo-barefoot running experiment has been going quite well… sort of. As reported earlier, switching from my standby trail runners (I avoid running on pavement whenever possible- boring and crowded) to VFF KSO Treksports reinvigorated my running. Initial observations included a lower heartrate for comparable time/distance, a much higher degree of engagement with my surroundings, and generally a greater desire to run more. I’ve kept it up, too. After an overly enthusiastic first outing that left me sort for a week I gradually built up my distance and am running the same distance in my VFFs as I was earlier in my regular shoes (~8-10km unless I’m feeling sluggish). In the process I have made a few additional observations.
1) ‘Burlier’ does not always mean ‘better’
I am already on my second pair of VFFs. The KSO Treksport boasts a number of very clever features, such as the knobblies on the sole (for hiking, scrambling over rocks, etc.) and some sort of tough rubberized patch on the topside of the toes to guard against abrasion if/when you trip on things or drag your feet. While these are both nice, they come at a cost. First, in order to prevent the lugs from feeling like little perma-pebbles underneath your foot, the KSO Treksport has a somewhat beefed up sole compared to the regular KSO; there is more padding, more rubber, and more stiffness. Not necessarily bad, but certainly counterproductive if you are trying to get as close as possible to the barefoot feel. The rubberized sections, on the other hand, are necessarily bad. I have only ever tripped once while wearing VFFs, and that was due to tall grass obscuring a largish root. That trip was pure end-on toe impact and did not result in significant abrasion to the tops of my toes; just a smashed up toenail and a little blood in the shoe. As such, the patch is functionless. But it has not been effectless. Because the patch does not stretch, and all of the fabric around it does, a bit of a tear developed at the edge of the patch, and grew fairly steadily over the next two runs. Yup: the feature specifically designed to prevent the toes from tearing tore the toes. Oh well. Normally I would just patch the sucker up, but I decided for once to take advantage of MEC’s absurd customer service (they REALLY stand behind everything they sell) and swap for the regular KSOs.
The regular KSO‘s have a very different feel to them. The soles are much more flexible (I especially notice it when moving my toes around- I can almost pick things up with my feet as though I were barefoot) and much thinner; you feel everything. These shoes still allow me to run over gravel more easily than I can barefoot, but certainly force me to be even more selective regarding foot placement. I recently suffered my first VFF-related injury (that sort of overstates it, but “VFF-related boo-boo” doesn’t sound as good) when I stepped hard on a sharp stone while coming down the hill on my usual circuit. While only a minor irritant, it caused some foot tenderness for a couple days. Nonetheless, running is just as much fun (if not more) in these as in the Treksports, and the trail engagement factor is even higher.
2) Going backwards is difficult
Running backwards is not difficult in these shoes. However, taking a footwear step backwards is. After nearly two months of running exclusively in VFFs I dusted off the old runners and gave them a couple goes around the lake. The results were interesting. First, my running form has certainly changed. Where I used to be a heel-striker, I now land forefoot or midfoot first, but with a thick-soled runner with a significant (12mm+) heel-toe drop, this puts my ankles in a more awkward position and seems to result in an overall feeling of less stability underfoot. One might argue that the soft sole accentuates this instability, but since I run largely on trails, and this feeling persists even over bark mulch (where the compression or displacement of the mulch likely outweighs the compression of my shoes), I am unconvinced. In any case, it feels icky.
Reverting to heel-striking has similarly undesirable effects, as I feel like I am working a harder to go the same distance. My heartrate monitor concurs. The specifics of why this is are beyond me, though a quick browse online suggests (to me at least) that muscle vibration may be a factor. A recent study by Friesenbechler et al. looks at how extended periods of running affects muscle tissue vibration (which in turn is supposed to affect fatigue). It looks as though as one runs, tissue vibration increases in intensity. This should result in an increasing fatigue positive feedback loop -hence why compression garments are supposed to help reduce fatigue. That said, chances are that the fatigue onset from increased tissue vibration due to heelstriking rather than mid/forefoot striking in a single decidedly non-elite runner (over <10km distance) is probably so minimal that it could be compensated for by eating a sugar cube, napping for 20 minutes, listening to upbeat music or something before going out. This is sort of like self-diagnosing an illness using google and a list of vague symptoms. “Holy moly! Nagging cough, general malaise… I’ve totally got alpha-1 antitrypsin deficiency!”
“But Nick,” you say, “why are you looking up articles in the Journal of Biomechanics when you should be writing your damn thesis?” That brings us to #3.
3) I like to be semi-informed (but not too informed) about things.
During a recent
procrastination session study break I recently came across this debate (in the comments section) regarding the barefoot/minimalist trend, wherein a fella who is head of research for Asics (but claims to speak as an individual and not as an Asics representative) argues that the science behind BF/Min running is somewhere between non-existent and bogus, and that the whole movement is just a fad. He challenges the blogger to cite any relevant studies supporting the notion that running barefoot is better than running shod. This brought up an interesting question for me: have I guzzled the barefoot Kool-aid? Have I suitably questioned the veracity of the claims behind the BF/Min movement, or am I just doing what’s cool? Well, I figured that if there’s one thing I can do quickly it’s find a bunch of articles online and skim their abstracts. Done. It turns out that there’s a pile of research. A big interesting pile, none of which seems to support the pro-shoes/anti-barefoot claims. Two abstracts were of particular interest (full disclosure: I didn’t read the articles- just the abstracts. I had work to do after all.):
Hasegawa et al. 2007 show that footstrike patterns among 1/2 marathon runners show a relationship between speed and footstrike. Faster runners have a midfoot or forefoot strike while slower runners run with a heelstrike. To my mind, this can be broken down a few ways. First, elite runners will generally have worked with some sort of coach to optimize their form, which likely results in concentrating on forefoot striking and efficient running. Non-elites (ie. me) with no coach, guidance or intervention plod along with subpar form (heel strike). In this context, BF/Min running may act as a material intervention that effectively forces a runner to adopt a more efficient running form. Heelstriking hurts when you have no padding, so you stop doing it. And second, in order to run faster, your foot turnover should be faster, and by reducing the heelstrike segment one can reduce ground contact time and increase turnover. Sprinters don’t heelstrike and they go really fast. Of course, what would happen if one of the elites was stuck running for four hours (or whatever the elite runner’s ultra-maximum run duration is)? Would they revert to a heelstrike to conserve muscular energy? After all, an elite can cover 21km in about an hour(!). I can keep up my good running form for an hour or so. But to run 21km (about my maximum non-stop running distance), I’m looking at a lot more time on the road, and I’m not sure that my calves would hold out that long. Even barefoot we tend not to walk on our toes, so perhaps there’s an evolutionary connection to heelstrike striding at slower speeds. Humans can walk efficiently all day by heelstriking and not engaging all those extra foot muscles, and we can maintain a pace high enough to exhaust a sprint-adapted quadruped by getting up on our toes and running.
Second, Hanson et el. 2011 have shown that running barefoot is approximately 5% more efficient in terms of oxygen usage than running shod. Wow. That’s the very same difference I observed in my own running. I am an ultra low-budget one person biomechanics lab (albeit with very limited publications in the field).
Based on these abstracts I feel somewhat more confident that my choice to (continue to) run with less shoe is based at least somewhat on scientific evidence as well as my own personal experiences, rather than on the ravings of partisan enthusiasts on one side or the other.