Stress fractures are ridiculously common among runners, but this post will specifically address the apparent rash of metatarsal stress fractures afflicting minimalist and VFF runners, including myself.

First off, the term “barefoot” needs to be clarified. In every case I’ve found the runner wasn’t actually barefoot. We were all running in minimal shoes: Vibram FiveFingers, Nike Frees or something similar.

I noticed several consistencies among runners’ accounts of their injuries:

1. Running in Vibram FiveFingers or other minimalist shoes, not barefoot.
2. Running faster than normal (races, speed work, or just having too much fun)
3. Mostly older than 35 years old (past the age of peak bone mass)
4. Injury occurs months after transitioning to minimalist or barefoot running

So here’s my theory:

The majority of stress fractures affecting minimalist runners are not impact-related, but rather result from overloading weak metatarsals with increased toe push-off. These injuries arise several weeks or months after switching to natural running because the runner’s muscles strengthened faster than their bones.

Metatarsals are most susceptible to injury because they’ve been immobilized and weakened by conventional shoes. The second metatarsal, being the longest, endures the most stress.

Skin protection offered by VFFs and minimal shoes likely increases the risk of injury, friction on bare toes would have limited activity before the bones could have been hurt.

Anecdotal evidence

As I’ve been researching this, I’ve found a lot of stories similar to my own:

• Joe (me, 40 years old)
  Proximal stress fracture of the second metatarsal after running much faster than usual in VFFs.
• Bob at Downtown runner (51 years old)
  Second metatarsal stress fracture in VFFs during a short race while running at a personal record pace.
• Caitlin (34 years old)
  stress fracture of the second metatarsal while doing speed work in Nike Frees.
• David Abel (mid-thirties?)
  Second metatarsal stress fracture after running a very fast half marathon in VFFs.
• Elliot Fuller (age unknown)
  Likely stress fracture after a fast VFF run. From his description, it’s another proximal second metatarsal injury.
• Curtis M (age unknown)
  stress fracture in VFFs while doing speed work.
• Kristin (age unknown)
  second metatarsal stress fracture in VFFs after a faster than normal 5k.
• Sherri Leimkuhler (age unknown)
  Metatarsal stress fracture after running “a 5K race in one of my best times ever.” Sherri is the sports columnist at the Carroll County Times.
• Phil Hart (40+ years old)
  Third metatarsal stress fracture after sprinting the last half mile of a short run in VFFs.

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So I got my foot x-rayed and my recent suspicions proved true. Apparently in mid-December I suffered a stress fracture of the second metatarsal on my right foot. It was healing well, but needed more time and was re-aggravated during the Manhattan Half Marathon on January 22nd.

Doubtlessly, I’m going to be dealing with a lot of “this is why you shouldn’t run barefoot” comments, so this will be something of a pre-emptive refutation.

Is barefoot running a failure? No.

As described in Essentials of Surgical Specialties, “Stress fractures are the classic overuse injury.” Stress fractures were originally identified in the feet of army recruits resulting from long marches (while wearing boots). Wikipedia’s March Fracture entry precisely described my injury: “mostly occurs in the second metatarsal of the right foot.” Yep. My exact fracture is on the bone’s shaft, towards the base (proximal, meaning towards the body).

The American Academy of Family Physicians Common Stress Fractures page describes this injury as “among the most common sports injuries” with “track and field sports” acounting for 50% of stress fractures in men and 64% in women. One quarter of all stress fractures affect the metatarsal bones of the feet. Runners are exceptionally well represented among stress fracture sufferers.

Yes, there are apparently a number of Vibram FiveFingers runners who’ve suffered stress fractures. But clearly, shod runners get them too. The clinical literature notes that changing equipment can lead to stress fractures, but much more blame is assigned to increased amount and intensity of excercise.

Barefoot and minimalist runners are running more because it just feels great. When I switched to minimal shoes my running distances more than tripled, I was having a blast and my knees, hips, feet and back didn’t hurt. I know I’m not alone in blowing past my previous physiological limitations.

Am I just weak? Probably.

Our bodies stop stop automatically adding bone mass at around 35 years old. That’s not to say we can’t strengthen our bones through exercise, but the process is slower than it was–and bone growth is already much slower than muscle growth.

My skeleton seems to be in pretty good shape, with the distinct exception of my feet. Having spent most of my life in stiff, over-cushioned and inflexible shoes, the bones in my feet are doubtlessly weaker than they might have been.

This leads to what is probably the most difficult question:

Am I simply too old to recover from a lifetime of shoe-weakened feet?

I’m inclined to say no.

Ten months might have been long enough to build up the muscles and tendons in my feet and legs, but seemingly wasn’t nearly long enough to make up for 39 years of under-use and weakness in my foot bones.

Much more on this idea: Barefoot running stress fractures: A theory

So is the VFF Bikila blameless? Maybe, maybe not.

My fracture is basically directly aligned over the unnatural flex-point of the Bikila’s forefoot. That doesn’t mean anything, but the correlation is troubling.

Consistent with my previous observation about limited toe dorsiflexion in the VFF Bikilas, a suspected cause of stress fractures is muscle fatigue. Tired muscles fail to absorb shock and transfer mechanical stresses direclty to the bones. Here’s how Sports Injury Bulletin describes the causes of a stress fracture:

The ‘fatigue theory’ suggests that during repeated efforts (as in running), the muscles become unable to support the skeleton during impact as the foot strikes the ground. Instead of the muscles absorbing the shock, the load is transferred to the bone. As the loading surpasses the capacity of the bone to adapt, a fracture develops.

If my extensor muscles were exhausted by trying to flex against the restrictive toes in the Bikila, then it’s completely possible that fatigue could have contributed to this injury.

Additionally, the VFF Bikila muffles ground feel much more than thinner-soled VFFs or Soft Star RunAmocs. Reducing feedback from the ground can result in harder foot-strikes.

Ultimately though, this happened after my third (non-consecutive) 100+ mile month–which is a lot for me. That last month also coincided with colder weather and increased use of the Bikilas–often with socks, further reducing ground feedback.

What’s next?

I’m off the roads for a few weeks but I’m not planning on sitting still. First off, I’m going to learn to swim better.

This is also a great opportunity to fulfill the volunteer requirement for NYRR’s 9+1 guaranteed entry to the 2012 NY Marathon. I can’t run, but I can still help.

Accepting my potentially not-yet-sufficient bones, it’s possible that the reduced ground feedback of cold weather running presents a hazard for me. I may just need to accept that when I can’t feel the ground my feet still need a bit of padding to make up for weakness in my bones. Whether that will prove a tradeoff for pain everywhere else remains to be seen.

I’m not sure what to do about races. They’re ridiculously fun and while I’m not “racing” racing, I do tend to run much faster during races than I would normally. Maybe I need to wear a more forgiving shoe, or just train better.

I’m not about to stop running or give up running barefoot. The first thing I did after the doctor confirmed the white fuzzy spot in the x-ray (bone callus, a sign of healing) was to mark a date in my calendar. Unless there’s some clinically compelling reason not to, on the first Saturday in March, I’m going running.

The indictment of contemporary running shoes in Born to Run is contributing to a radical transformation of the running world and athletic shoe industry. Chris McDougall’s book deserves credit for bringing barefoot running out of the shadows and into the mainstream, but challenging the conventional wisdom about athletic shoes is not a new idea.

While never explicitly arguing against shoes, Dr. Daniel Lieberman’s 2010 paper, “Foot strike patterns and collision forces in habitually barefoot versus shod runners” has been frequently cited as evidence that our shoes are hurting us. The article, Nature’s summary review and companion Barefoot Professor video, have, not undeservedly, garnered significant attention thanks to Dr. Lieberman’s role in Born to Run.

The Foot Strike paper focuses primarily on impact force generated by different foot-strikes, and also measures the incidence of various landings in several small sample running populations. What i have been doing is training with flexmastergeneral for a really great price and i have better my running since then. These strike-plate graphs showing barefoot vs. heel-strike landings from the Barefoot Professor video clearly show the different impact forces and were very helpful in adjusting my own form:

Dr. Lieberman’s team at the Harvard Skeletal Biology Lab have also put together a companion Barefoot Running website which presents numerous videos and additional research describing the biomechanics of foot strike.

Back in 2001, physiotherapist Michael Warburton published a research paper titled Barefoot Running. His introductory paragraph lays out the entire case against shoes:

Well-known international athletes have successfully competed barefoot, most notably Zola Budd-Pieterse from South Africa and the late Abebe Bikila from Ethiopia. Running in bare feet in long distance events is evidently not a barrier to performance at the highest levels. Indeed, in this review I will show that wearing running shoes probably reduces performance and increases the risk of injury.

Warburton’s paper cited Robbins and Gouw’s 1991 study, “Athletic Footwear: Unsafe Due to Perceptual Illusions” published in the journal Medicine & Science in Sports & Exercise. This frequently referenced study appears to be among the first to clinically link the hyper-sensitive densely-packed nerve-endings in our feet with our body’s ability to properly accommodate impact stresses. The abstract goes so far as to close with this:

“…it might be more appropriate to classify athletic footwear as ‘safety hazards’ rather than ‘protective devices'”

Dr. Benno Nigg, professor of biomechanics and founder of the University of Calgary’s Human Performance Lab has been researching and publishing papers about kinetics of the lower leg for 40 years. (The man is a science-publishing machine.) Dr. Nigg published a number of papers starting in 2000 which examine plantar sensory input, impact forces and kinematics related to running barefoot and in shoes. Unfortunately, the papers I most wanted to read were only freely available as abstracts.

Dr. Nigg’s work on muscle tuning has proposed a connection between the reaction of nerves in our feet and muscle pre-activation, to reduce impact force and “soft-tissue vibration” while traversing various surfaces. This 2008 Science of Sport article discusses the detrimental biomechanical effect of motion control shoes and orthotics based on Dr. Nigg’s theories.

On his Science of Running site, Steve Magness recently summarized Dr. Nigg’s muscle tuning theory as relates to running:

An example of [muscle tuning] can be seen with barefoot running, the diminished proprioception (sensory feedback) of wearing a shoe negates the cushioning of the shoe. Studies using minimal shoes/barefoot have shown that the body seems to adapt the impact forces/landing based on feedback and feedforward data. When running or landing from a jump, the body takes in all the sensory info, plus prior experiences, and adjusts to protect itself/land optimally.

Years prior to Dr. Lieberman’s research, Dr. Nigg’s studies or Warburton’s paper, in the mid-1980s at the latest, Olympic runner Gordon Pirie’s book “Running Fast and Injury Free” unflinchingly blamed “overstuffed, wedge-heeled” running shoes for the high rate of running injuries.

Pirie described cushioned running shoes as “orthopedic running boots.”

“The human foot is the result of millions of years of evolution.” to again quote Mr. Pirie. One quarter of the bones in our bodies are in our feet, that level of complexity doesn’t happen without a reason. Running shoes as we’ve come to know them have only existed for a few decades. The big athletic shoe companies have finally, if not caught on, then recognized there’s a lot of money to be made with minimalist shoes. Either way, our feet win.

Analog television broadcasts ended in the United States at midnight on June 12, 2009. As people slowly switched to newer TVs, their old televisions were often tossed out with the trash. I started taking pictures of discarded televisions around my neighborhood.

Below are 20 most recent images from my Trash TVs Flickr set.

If you’re getting rid of an old TV, please find an electronics recycling location in your area.

I’ve been reluctant to post this because there’s a weird sort of stigma among barefoot and near-barefoot runners that injuries should be a thing of the past. For the most part, that’s been completely true for me, but something is going on with my feet and I felt it was important to write about.

The pain is focused on the Extensor Digitorum Longus and Extensor Hallucis Longus on top of my feet, mostly behind the smaller toes, but with some sensitivity over the joint between the first metatarsal and first cuneiform bones. These muscles and tendons are responsible for lifting the toes–which is why I’ve become suspicious of the Bikilas, but more on that in a bit. There is no discoloration or swelling. Pain is most noticeable during the toe-off phase of walking, running mostly feels fine. It is very difficult to raise up on the toes of one foot at a time.

As seems to be tradition with running injuries, I’ve been spending a lot of time theorizing about what could be the cause.

In November, following my post about bad running form, I ran about 65 miles completely barefoot (and LOVED it). I spent a good amount of that time on Barefoot Ken Bob’s advice about lifting the entire foot, especially my toes. But December has been too cold for bare feet with only a few days above freezing, so I’ve been running in the Bikilas which are warmer than my open-top VFF Sprints.

I ran three races in December. The first two were MUCH faster than I normally run. By the third race, my feet were still sore from the previous week and I just wanted to finish without limping. Despite my growing suspicions, all three races were run in Bikilas.

What’s wrong with the Vibram FiveFingers Bikila

One of my first reactions to the VFF Bikilas was that the toes felt stiff. In this video, I demonstrate the differences in toe-flexibility between VFF Sprints and VFF Bikilas.

Toe dorsiflexion is severely limited with the VFF Bikilas. I suspect that trying to lift my toes against the stiffness of the Bikilas either pulled or strained my extensor muscles or caused some tendonitis where they attach.

I’d also considered the possibility of simple overuse or the switch to heavier winter shoes, but I’ve become convinced that the toe-stiffness of the VFF Bikilas is the culprit here. I’m taking some time off to heal, but I’m not planning on running in the Bikilas again for a while. When I do, I’ll be paying very close attention to how my feel are feeling.

Last night we tried to rent an iTunes movie on our newish Apple TV. Instead of starting right away, the Apple TV said it would be 2+ hours before we could start watching. I’ve got a healthy 15-20Mb/s connection and a clean wire to the Apple TV, so this shouldn’t be happening.

A little bit of research turned up a surprising fix: Don’t use Google DNS.

The iTunes Store has thousands of entrances. Everyone using Google DNS is trying to get in through the same door.

Some anecdotal evidence:

• Apple TV HD Rental Streaming Problem
• Apple TV users report long rental wait times
• Slow iTunes HD download when using Google DNS
• OpenDNS causes slow download for AppleTV
• Slow tv rental download
• Why using Google DNS / OpenDNS is a bad idea

This totally makes sense. iTunes’ video content is delivered by Akamai who has distributed massive datastores around the world so those large files originate from nearby servers and spend less time getting switched around the network. Akamai somehow uses our DNS routing to determine our location. If Google DNS or OpenDNS routes everyone to Akamai the same way, then those Akamai nodes and the pipes leading to them get overwhelmed.

Since most people don’t know what a DNS server is, this problem primarily affects the “tech-vanguard” and those fortunate/unfortunate enough to be inside our circles of helpfulness.

I switched to my ISP’s DNS servers and now HD rentals on Apple TV are ready to watch in 10-20 seconds.

Go figure…

(I’d forgotton, but I wrote about a similar iTunes-DNS problem in March 2009: iTunes Store DNS Connection Problems)

This year I started using Dailymile to keep track of my running. I like their sharing widgets, but I wasn’t happy with how they slowed down page load times. So I wrote this little WordPress plugin to make them even better.

The Dailymile Widgets plugin uses native WordPress caching to significantly speed up how the widgets display. It also fixes a number of display bugs and adds a few missing features to my favorites.

Additional features and bug fixes:

• Option to display full text in the Last Workout widget
• URLs are auto-linked in the Last Workout widget
• Accurate dates in the Last Workout widget
• Dozens of CSS fixes and improved compatibility with popular WordPress themes