"Never be limited by other people's limited imaginations. If you adopt their attitudes, then the possibility won't exist because you'll have already shut it out." -Mae Jemison, astronaut

Tuesday, May 13, 2014

Permission to Buy More Shoes! (Research Says, After All...)

When it comes to the stereotype about girls and shoes, I don't much fit. I figured you needed a brown pair and a black pair. In later years, this expanded to include a brown and black set of heels, too. The bonus with this mentality is that it keeps clothes shopping simpler. If you can't wear one of the 4 pair of shoes with it, you can't buy it.

Running shoes were even simpler. I had one pair, which I used solely for aerobics sessions and a few squash games. I did the "grapevine" and wore leg warmers and had a lot of hair held just-so by a lot of hairspray (gosh I hope they don't link that stuff to cancer in a few years!)

When I started running my 30 minute sessions outdoors about 14 years ago, my one pair system seemed fine. Then I started trail running in 2006 and got stuck in a car pooling van with 6 or 7 mad ultra runners who seemed to talk endlessly about all their shoes. I learned quickly that my one set of road shoes was no good, primarily for two reasons: (1) traction and (2) dry-ability. If they got soaked in mud and snow, they needed a few days to dry out. And there was no way they could be used indoors for anything again!

Here I am another 8 years on and I own no less than 12 pairs of running shoes. And that's after just throwing out two pair last week! Why so many?
Most of the current shoe family

Two reasons for me. First, specificity. Second, an increasingly gnawing feeling in my gut over the past couple years that by changing shoes several times in a week, I can help avoid repetitive strains. I've got shoes that are better suited to road, trail, sand, and pea gravel. I've got shoes in larger sizes for long races and for other times when my feet are swollen. Most of my shoes are now really lightweight (a transition I made over a few years, based on research and comfort) but I've got some beefier shoes for uber-long stuff like multi-days or backpacking or if the bottom of my foot has some sore spot.

Research over the past couple years has seemed to support this - runners with more shoes experienced fewer injuries. Rather than "breaking in your shoes", research started suggesting that shoes break in our feet! (And the rest of the chain of tendons/muscles/ligaments/joints up through knees and hips). Our bodies adjust to the shoes. The shoes do very little to adjust themselves. We change our mechanics. This seemed to ring true for me when I tried on a pair of "maximal" type highly cushioned shoes a while back. I had knee pain within 2 km. Around km 8 it abated, as I think I was learning how to adjust my gait for the shoe. Same thing happened on the next run. I sold the shoes. They just didn't feel natural. I subscribe to the theory put forth by some shoe/foot biomechanics researchers that if you put a shoe on and it immediately feels good, it's likely a good shoe for you. If it pushes your arch or feels awkward in some way as you run, it's probably not suited to you.

I was recently alerted to a 2013 article in the Scandinavian Journal of Medicine & Science in Sports which looked at 264 runners over 22 weeks. They separated runners into those who wore just one pair of shoes or those with more and compared injury rates. You know where this is going! Runners who used more shoes had lower injury risk. Why?
Shoes like views, too!

The authors hypothesise several reasons, which have come out of previous research findings. Shoe characteristics impact our running pattern. Runners in flatter shoes (less heel drop), reduce impact/shock at the heel. Worn out shoes (loss of cushioning, as one factor) cause us to increase stance time and change the dorsiflexion/plantar flexion patterns as we land and toe-off. Thus, if we change shoes more, we change the load applied to the musculoskeletal system at different points and should therefore be less prone to a repetitive load and overuse injury.

On March 31st, a very important paper was released, which I only found out about by my taking time to listen to a trail running podcast (something I haven't done in over a year!). The paper is a position statement issued by the American College of Sports Medicine (ACSM) on "Selecting Running Shoes." I mistakenly thought they hadn't issued a statement on shoes before, but it appears they had. Only the statement from way back contained all that old stuff: We should all run in highly cushioned, supportive, elevated shoes. The beautiful thing about science, no matter the discipline, is that theories are put out there and then scientists go about madly testing them. The tests of the past 10 years, as experiments and equipment became more fine-tuned, started refuting this theory. Indeed, the ACSM statement reads that there are three characteristics of a "good, safe running shoe": (1) minimal heel-to-toe drop, (2) neutral, and (3) light in weight.
Avoiding the shoe dilemma altogether.

I'm sure putting this in writing took a few years of hard work, reviewing the massive amount of literature in order to back up statements made. Nothing easily gets approved in big organisations, especially where public health and credibility to one's organisation are at stake. It will be interesting to watch what happens now in the shoe industry over the next two years. There are a lot of high drop, highly cushioned, stability shoes sitting on the market. And, indeed, at the level of the runner, a shift to this kind of shoe can require (as noted in the statement itself) biweekly strength training and a couple months of adaptation for the musculoskeletal system. Patience is not always what runners do best. If it was, I expect we'd all be really good chess players or customer service reps :)

Speaking of reps, it's time for my strength training session. Second of the week, too, coincidentally.