Wednesday, December 16, 2015

How much easier is running on an AlterG? Developing equal-intensity curves for anti-gravity treadmill running

Have you ever run on an AlterG? Once firmly in the realm of space-age gadgetry only available to professional athletes, AlterG anti-gravity treadmills seem to be cropping up everywhere nowadays.  College athletic departments, physical therapy offices, and even the occasional high school are purchasing AlterGs for their widely lauded ability to allow runners and other athletes to continue to train pain-free even with significant injuries.  By reducing your effective body weight, the AlterG allows you to run at normal training speeds with drastically reduced impact and active forces.  With careful modulation of the body weight settings, you can often maintain running fitness even during the rehab period of formerly season-ending injuries like a stress fracture. 

The AlterG achieves its anti-gravity effects using a pressurized "bubble" that encapsulates the runner's lower body.  Special compression shorts with an airtight skirt zip securely into a thick vinyl bubble that surrounds a standard running treadmill.  The heart of the AlterG, a computer-controlled air pump, inflates the bubble to above atmospheric pressure, applying an evenly-distributed force from air pressure to the runner which counters the force of gravity.  By adjusting the air pressure inside the bubble, the AlterG can adjust your effective body weight. The AlterG uses a force plate to correlate changes in the bubble's internal air pressure and your effective weight while standing on the treadmill.

In the past few months, I've been fortunate enough to have access to an AlterG.  I've also been fortunate to not have to use it for any injuries (knock on wood...), so I used the opportunity to look into a question that I've been wondering since learning about the AlterG: How much easier is running on an anti-gravity treadmill compared with running on land?

Because the majority of the metabolic cost of running comes from absorbing impact and accelerating your body weight against the force of gravity to propel yourself forward, it's axiomatic that reducing your effective body weight while maintaining the same running speed will reduce the energetic cost of running.

Notably, this is not the same situation that occurs when a runner loses weight normally—if a 150 lb runner decreases his weight to 140 lbs by restricting his caloric intake, muscle loss is inevitable (this is part of the problem with the idea of "racing weight").  Though he now weighs less, and thus the energetic cost of running a given speed is decreased, he has also lost some muscle, so his ability to produce energy is reduced as well.

There's no good bio-energetic equation to predict the metabolic cost of running; the only way to get a good answer would be with an experiment, which I set out to conduct. 

Friday, August 7, 2015

Designing a general strength circuit for distance runners

Weights, general strength circuits, plyometrics, and hip/core strength exercises all have their place in the training of a distance runner.  Today, I'd like to focus on general strength circuits specifically. 

Each word in that phrase has a particular meaning.  General means not specific. i.e. not exercises that are very similar to running or that involve running.  An example of a more specific strength exercise might be uphill sprinting or bounding.  Strength means more or less what you'd expect it to be—resistance exercises for muscular strength.  Finally, circuits denotes that we're talking about a high-intensity strength routine with many different exercises and short recovery. 

Why should a distance runner do this type of strength work? There are three reasons, and each of them illustrates one of the three domains from which a good coach will draw wisdom.

Why do strength circuits?

1.  Anecdotal observations on strength

The first domain is anecdotal observation.  Subjectively, I (and a lot of other coaches) have noticed that fast, injury-resistant runners tend to be stronger and more athletic than their slower, injury-prone counterparts.  Of course, there are exceptions—a skinny, uncoordinated kid who wins the state meet, for example—but if you spend enough time around budding distance runners, you'll find the general trend is undeniable.  This alone is reason enough to do some type of work for improving strength and general athleticism, since it's also evident to any experienced coach that "just" running won't make you strong and athletic.

2.  A physiological argument for strength circuits

The second is drawing from physiology and training theory.  In distance training, we know that it is advisable to build a base of general, less-specific running before moving to race-specific workouts.  We can apply the same principle to both strength work in general and to high-intensity circuits in particular.  Before we start doing any heavy weight lifting, high-intensity plyometrics, or hill sprinting or bounding, it makes sense to improve our general strength and athleticism so we're better-prepared for higher-intensity, more running-specific stimuli further down the road. 

Additionally, there's a general-to-specific argument to be made for high intensity circuits with regards to development of a finishing kick.  Think about what happens when you kick at the end of a race: you call upon your fast-twitch fibers to work at a high intensity, even though they're already awash in acidosis.  We can train this in a specific way by doing certain workouts (or just by racing), but how could we train, in a general, non-specific way, the ability to recruit fast-twitch fibers in a fatigued state? A general strength circuit is the perfect solution.

 3.  Scientific research on strength circuits and hormone levels

If you keep up with pro running news, you'll know that there has been a lot of buzz recently about the possibility of illegal doping being much more widespread than was previously thought.  There are three go-to pharmacological aids for drug cheats: EPO, which boosts your red blood cell production, testosterone, which boosts muscle growth and recovery, and human growth hormone, which also aids in muscle growth and recovery.  Wouldn't it be great to be able to boost levels of these hormones naturally?

With EPO, we're out of luck unless we live at altitude, but with regards to hGH and testosterone, the situation is a little more interesting.  Scientific research shows that a general strength circuit designed with a couple of guidelines in mind will boost levels of human growth hormone and testosterone in the blood for several hours post-exercise.1

By now, it should be clear that strength circuits should be a part of any competitive 800m to 10,000m runner, and should be a serious consideration for long-distance runners from a recovery and injury-resilience perspective too.  The next question is how to actually design a general strength routine.  To do so, we'll look to the scientific literature for guidance. 

Wednesday, August 5, 2015

My history with loss of leg coordination while running

I try to avoid anecdotes and personal histories when dealing with running injuries.  They're fraught with the dangers of recall and confirmation bias, and worse, people seem hardwired to give more credence to a personal story than reams of scientific data.  But in the case of loss of leg coordination, I don't really have a choice—the scientific data is extremely sparse, and there aren't even any case studies in the medical literature describing anyone with the hip-centric loss of leg coordination symptoms that seem to be a variant of "runner's dystonia."  On top of that, I know of only a handful of people who claim to have made full recoveries from the loss of coordination problem—and I'm one of them.  As you read my account, remember that I'm not a doctor, and I'm also not an unbiased observer.  My views on solving loss of leg coordination are no doubt informed by my own experience.  For a more objective review of the problem, see my extensive article on loss of coordination published last week, or the executive summary.

*   *   *


To understand my story about loss of leg coordination, it will help to have a bit of a background on my journey as a runner.  I started running cross country and track as a freshman in high school, having done a little bit of each sport in middle school.  I didn't become a runner until my sophomore year of high school.  Until then, my times were decidedly unimpressive, and I did not train in the offseason or take the sport seriously.  Starting in fall my sophomore year, I began running year-round.  I was not particularly athletic, so I did not have other sports to do in the winter and summer anyways.  Plus, I wanted to see if I could improve.

And I did—I dropped from 5:40 in the mile as a freshman to 4:40 as a junior.  During those two years, I started experimenting with doing longer runs (12+ miles), and even ran Grandma's Marathon after my sophomore and junior years.  I did not start doing what I would now consider "high mileage" until before my senior year; that summer, I had a few weeks around 80 miles, and that winter, I averaged over 70 miles a week for almost three months, with a high of 90.  Again, this paid off, and it set me down the path of being a high mileage runner.  Throughout high school I was eminently healthy; I never missed a single day due to injury.

I ran in college, and continued improving thanks to high mileage training.  A few 100-mile weeks my freshman year dropped my times further, and going into my sophomore year, I logged eleven weeks in a row over 100, including several at or above 120.  This culminated in probably the best race of my career, a 25:34 cross country 8k in Wisconsin.  I missed that winter for a non-running-related injury, but with that exception, I did not miss much time due to injuries until my junior year.  Starting that summer, and for the rest of my college career, my progression was interrupted by overuse injuries, mostly in my hips and feet.  Later, I would realize that a lot of these were likely the result of not enough hip strength work, but that's a story for another time.

In many ways, my background fits the typical profile of a runner who develops loss of leg coordination: young, fairly serious and competitive about training, and a history of high-volume training.

Friday, July 24, 2015

Loss of leg coordination while running as a task-specific focal dystonia distinct from runner's dystonia: an executive summary of findings

Loss of leg coordination while running as a task-specific focal dystonia distinct from runner's dystonia
An executive summary of findings on loss of leg coordination while running

John Davis

 Loss of leg coordination while running is the working term for a rare neurological problem that occurs in long distance runners.  It is characterized by a gradually increasing sensation of tightness, weakness, and poor coordination in the muscles of one leg that occurs only while running—stopping to walk or stand still all but eliminates the symptoms.  Runners with loss of leg coordination cannot point to a specific area of pain; rather, there is a more general feeling of tightness, vague aching, and an overwhelming sense of something being "off" with the functioning of the affected leg when they run.  Further, classic signs of neurological injury, like numbness, shooting pain, or a "pins and needles" sensation, are absent.

These symptoms are also highly specific to running.  Other activities, even cyclical and highly aerobically demanding ones like using an elliptical or riding a bike, do not reliably recreate the symptoms.   The loss of coordination sensation is typically localized to the muscles which are the prime movers of the legs: the calves, the hamstrings, the quadriceps, and the gluteal muscles.  Despite the weak, uncoordinated sensation while running, absolute muscular strength is normal. 

In most cases, running longer, faster, and on flat surfaces exacerbates the problem.  Some runners find they lose coordination with any kind of running, but most are able to run at an easy pace on rough terrain (e.g. on trails or over cross-country).  Short intervals of fast running are not usually a problem, but longer intervals at fast speeds and especially fast continuous runs and races bring on loss of leg coordination more rapidly.  Ceasing a run makes the loss of coordination sensation go away almost immediately, but some lower leg muscular tightness can persist for a few days after a particularly bad episode.

Searching for answers on loss of leg coordination while running: a comprehensive review

This is an extremely long article.  For a shorter executive summary, click here to read in your browser, or click here for a printable PDF version.

 Most of the injury articles on this website are long, detailed, and rigorously cited, with their claims being supported by solid scientific evidence.  Although this, too, is an injury article, it is not like the rest.  The topic of this post is a rare and frightening phenomenon that I and others have tentatively termed "loss of leg coordination while running."  This is an "injury" of sorts that has affected me and, as a very long thread on has made me aware, many other runners.

Because medical and scientific literature on this problem is scant, much of what follows is based on reports from runners with loss of leg coordination and logical inferences from what's known about how the body works it is running correctly.  Because of this, you should view everything I have to say below with skepticism, especially because I'm not an unbiased writer (having suffered from this problem for quite a while before recovering). 

I told myself I would write this article when I was able to run 50 miles per week again with some faster running.  That point came and went a long time ago—it was far easier to get distracted by my own running again, but it's long past time I write this article.

The working definition of loss of leg coordination is something that I've come up with by analyzing as many descriptions of the problem as I can find.  Much, though not all, comes from posts on the thread. 

Put in its most universal terms, "loss of leg coordination while running" is characterized by a gradually increasing sensation of tightness, weakness, and poor coordination in the muscles of one leg, but only while running—stopping to walk or stand still lessens the symptoms.  There isn't pain, per se, just tightness, vague aching, and an overwhelming sense of something being off.  And the sensation of losing coordination isn't localized to any precise area; rather, it is associated with a more general feeling of your leg not doing what you want it to do.  It feels like your stride is just "off," like your leg just won't go.  Instead, it flops along uselessly. 

Further, these symptoms seem highly specific to running.  Other activities, even cyclical and highly aerobically demanding ones like using an elliptical or riding a bike, do not reliably recreate the symptoms.   The loss of coordination sensation is typically localized to the muscles which are the prime movers of the legs: the calves, the hamstrings, the quads, the calves, and the glutes.  Some people find that the tightness and poor coordination progress from one muscle group to another as the problem worsens, but there isn't any distinct pattern to this.  Some posters find that their problems start in their feet or ankles and progress upwards, while others have issues in the thigh and calf only.  Though these muscles feel weak and uncoordinated when you run, you can head into the weight room and do just as much weight on hamstring curls, leg extensions, and single-leg squats on your "bad" leg as you can on your good one, so there is no frank loss of muscular strength.  Though this initial wave of symptoms might sound similar to a nerve problem like sciatica, there is not usually any numbness, shooting pains, or "pins and needles" feelings like you would expect with a nerve problem. 

Certain running conditions also exacerbate the problem.  Running faster magnifies the degree to which coordination in the leg is lost, with high speeds resulting in the leg seeming to flop around uselessly, while the opposite leg (the healthy one) picking up the slack.  Puzzlingly, flat, even surfaces like tracks, roads, and treadmills bring on symptoms to a much greater degree than uneven terrain like trails or grassy cross country courses.  Some runners describe being able to complete very long and challenging runs or workouts without any problem on rough terrain, but being completely unable to run any faster than a slow, easy pace on flat surfaces.  Other runners are able to run at an easy pace, but cannot complete any workouts involving faster running.  Some experienced problems at virtually any pace, though faster running on flat surfaces certainly magnified the issue.  Stopping makes the loss of coordination sensation go away almost immediately, but some lower leg muscular tightness or "off-ness" can persist for days after a particularly bad episode, even if you aren't running on the following days.

Further complicating the diagnostic puzzle is the fact that continuing to train with loss of leg coordination often causes a slew of secondary injuries because of the abrupt change in stress on the body.  Several runners reported foot, knee, and hip injuries that occurred concurrently.  In my case, I suffered a sacral stress fracture.  The people with this problem also have the usual smattering of Achilles, plantar fascia, knee, and shin issues that are common in regular runners. 

Add on top of that all numerous health-related idiosyncrasies ("I get tingling sensations in my left elbow," "If I flex my hamstring on my bad leg for a while, it cramps up," "I tore my hamstring playing hockey when I was 12 and have a lot of scar tissue"), plus the rarity of the problem, and you've got an incredibly difficult to diagnose issue.  It's not even clear that all or even most of the people posting about this issue online even have the same problem. 

Doctors, physical therapists, chiropractors, and any number of other medical professionals seem unable to pin down the problem.  Some of the posters report seeing dozens of different doctors and spent thousands of dollars yet coming back empty-handed.  MRIs, nerve conduction studies, and other diagnostic tests either come back clean or identify fairly common issues that are often asymptomatic, like a herniated lumbar spine disc.  Runners report that physical therapists and chiropractors inevitably find muscular weakness or tightness, often in the hip muscles and hamstrings, but they report that their rehab exercises have, at best, very limited and short-term success.

Saturday, July 11, 2015

Running specialization for young athletes: when should you become a year-round runner?

As my bio states, one of my areas of interest as a coach and writer is long-term development for young athletes: what is the best way to take a talented young runner and maximize his or her ability, both in high school and college/beyond? I've been thinking a lot recently about the idea of specialization—at what age is it appropriate or optimal to become a full time distance runner who trains year-round instead of doing other sports?

Perhaps eight or ten years ago, opinion in the running community leaned pretty heavily towards early specialization.  AAU track meets were (and to some extent, still are) popular for runners in elementary and middle school, and high school cross country programs saw a lot of growth in numbers when they started integrating a middle school "feeder program."  In the past few years, however, it feels like momentum is swinging back towards not having runners focus exclusively on running until a lot later—continuing to be multi-sport athletes throughout all of high school, in some cases.  I think the genesis of this was the success of runners like Grant Fischer, who played soccer up until his senior year of high school, plus backlash against hyper-early specialization in big-money sports like football and hockey, where training can completely take over your life, even at a young age. 

Coaches pushing ever-younger kids into two, three, or four-hour daily practices, plus the pressure of performing well at such an early age, can have some real negative consequences on enjoyment of the sport for a young athlete.  At the same time, missing out on too much of the fundamentals will definitely put you at a technical disadvantage, at least temporarily, compared to your competitors. 

This is true for most team and skill-based sports, but what about running? As distance runners, we trade in technical proficiency for raw physiological fitness, and because our sport is a repetitive, high-impact one, we can't put in long hours of training at a young age like swimmers or lacrosse players can.  The typical middle school or high school runner runs cross country and track, perhaps doing a bit of summer running before cross country, but does not train at all over the winter.  Maybe he or she plays basketball, swims, or does indoor soccer.  At what point should we encourage a promising young distance runner to fully commit to the sport? And are there any disadvantages to dedicating yourself to distance running at an early age?

When is the latest you should commit to year-round running?

There's no denying that having a strong lifetime mileage base is important in distance running.  The age of the top runners in the world for each event is proportional to the race distance: The best 1500m runners are 23-24, the best 5k and 10k runners are 26 to 28 years old, and the best marathoners are often in their thirties.1  The older you get, the more lifetime training you can accumulate, and the stronger your aerobic system can be. 

Additionally, a particular race distance has a certain minimum level of training that is required to in order to run it well.  Barring a few supremely talented exceptions, nobody runs a great 10k off thirty miles a week.  The question for the high school runner, then, is "How many consecutive training cycles are required to reach an adequate training level for 5k cross country and 3200 meters?"

Sunday, June 28, 2015

Basic Training Principles is FREE to download on Kindle for the next 2 days!

Quick update! Through Amazon's KDP Select program, I'm able to run limited-time free promotional campaigns for my e-books.  At 12:01am PST on Monday, June 29th, my first booklet, Basic Training Principles for Middle and Long-Distance Running will be FREE to download and share forever for the next 48 hours! Get your copy while you can!

If you don't already know about Basic Training Principles, here's the blurb!

"Rome, 1960. World record holder Roger Moens headlined an impressive field in the men’s 800m final at the Olympic Games. At the gun, Moens led with a fast pace, and by 600m, the lead pack had thinned to five runners. It looked to be a sure victory for the Belgian. But then, something curious happened..."

So begins Basic Training Principles for Middle and Long-Distance Running, a short booklet which gives you an introduction into the structure of a proper training program through the eyes of Arthur Lydiard's legendary training methods, first described in 1962. This booklet is short, gripping, informative, and written at a level which even complete novices can understand. It is designed to be an introductory lesson in fundamental training methods for newly-minted competitive runners.

This booklet was written to get young, promising high school runners eager to embark on a training journey and to set them on the right track for long term development, but any runner, young or old, newbie or veteran, can gain something from Basic Training Principles.

 Thanks as always for your support and I hope you enjoy this free deal! If you enjoy it, it would be fantastic if you could leave a review! Click here to go directly to the Amazon e-book store for Basic Training Principles.  Sometimes it can take the free deal a few hours to kick in, so if it's still priced at $0.99 at midnight PST, wait 'til morning and it should be free! The deal lasts until 11:59pm on Tuesday night.

Saturday, June 27, 2015

Modern Training and Physiology & Basic Training Principles are now available on Kindle!

Exciting news! My first full-length book, Modern Training and Physiology for Middle and Long-Distance Runners, is now available on Kindle! It took a bit longer than expected to convert the book to a Kindle-friendly format, but it's finally done.  The paperback version of Modern Training is still available on Amazon if you want a hard copy.

There are two great things about the Kindle edition.  First, it's only $3.99! And second, if you've already bought the hard copy, you can buy the Kindle edition for 50% off with the Amazon MatchBook service! Handy if you've already read my book but want to be able to reference it on the go.

Additionally, you can also find Basic Training Principles for Middle and Long-Distance Running on the Kindle store.  Basic Training is an introductory booklet to running training aimed at middle and high-school aged runners (though anyone can learn something from it!).  Basic Training is listed at only $0.99, but better, it will be completely free from June 29th to June 30th! Be sure to download your free copy on this upcoming Monday or Tuesday.

If you enjoy either of these books, please write a review on Amazon and tell your friends! Modern Training and Basic Training are the culmination of many years of work, and your support makes it all worth it. Thanks to you, Modern Training has sold almost 1,200 copies! Now, that's not going to impress any publishing industry big-wigs, but that's still pretty cool.  Over one thousand runners have bought this book! Now it's accessible to even more people through the Kindle store.

Friday, June 5, 2015

Light therapy for sports injuries: a case study in dubious modalities

In my upcoming book on preventing and managing running injuries (which, I'm sorry to say, is still very much a work in progress), one chapter discusses the roles various medical professionals can fulfill in the prevention, evaluation, and treatment of running injuries.  In many cases, a particular discipline is best-suited for one particular role: a podiatrist is ideally qualified to make custom orthotics, an orthopedist is best-suited to order and evaluate an MRI, and a physical therapist is the right person to create a rehab exercise routine. 

This does not mean that medical specialists see their own role with this narrow view.  There are plenty of physical therapists who prescribe orthotics, chiropractors who order and evaluate MRIs, and so on.  Perhaps because of pride or just a desire to manage all aspects of a patient's treatment, specialists sometimes have a tendency to stray outside of the boundaries of what they do best. 

In my view at least, the primary use of a physical therapist for an injured runner is as a resource for discovering muscular tightness or weakness that contributes to injury, evaluating running gait to identify any biomechanical flaws, and developing a rehab program to return to healthy running.  There are many fantastic physical therapists who focus almost entirely on these aspects of injury treatment. 

But many other physical therapists are wedded to their "modalities"—in-office treatments that purportedly improve healing or reduce pain.  The ones you are probably most familiar with are therapeutic ultrasound and electrostimulation (also known as TENS), but there is a veritable cornucopia of modalities that are sold to physical therapy clinics which claim to reduce pain, speed healing, or otherwise assist with the rehab process.  Some modalities even have research supporting their use, though this almost inevitably consists small, uncontrolled trials. 

Today I want to break up the allure of technological modalities by looking at one specific example called "light therapy."  Though it might sound like a quasi-mystical alternative treatment, light therapy is a real modality used in many physical therapy clinics.  The claim is that an intense beam of light, usually generated by light-emitting diodes (LEDs) or sometimes lasers, can penetrate the skin and stimulate mitochondria in the muscle cells if the light is of the correct wavelength.  The stimulation of the mitochondria allegedly speeds healing from fatigue and injury.  Again, this sounds borderline crackpot-physiology, but that idea is from a real study published in a scientific journal.  

To show that the light therapy machines used in a typical PT clinic are most likely useless and overpriced, I don't have prove that specific wavelengths of light have no effect on muscular mitochondria.  I just need to prove it is no better than any other basic source of light. Like, say, the Sun.

The sun is a really fantastic source of light.  As an exceptionally large black-body radiator, it puts out a wide spectrum of very intense light.  Part of this spectrum is in the "therapeutic photon" range of 600 to 1000 nm cited in marketing literature for light therapy devices.

Now, how does the photon output of the sun compare to a typical light therapy machine? We'll take a look a typical machine from Dynatronics, a company which produces equipment for physical therapy offices.  I don't mean to pick on one particular brand—light therapy equipment by Dynatronics is largely identical to products from other companies when it comes to technical specifications—we just need one specific machine to draw technical details from.

Tuesday, May 19, 2015

Twin Cities 1 Mile in retrospect: How slow was it? A statistical analysis

2015 TC 1 Mile Champions Garrett Heath and Heather Kampf

The Medtronic Twin Cities 1 Mile is one of the premier road miles in the United States.  It has hosted Olympic medalists and has borne witness to several sub-four-minute miles.  In addition to a top-flight pro race, the TC 1 Mile features several "open" waves, which usually total over two thousand finishers.  The traditional course was flat and very fast.  This year, the installation of a new light-rail transit line forced the course through downtown Minneapolis to be changed, likely permanently. 

This course change was announced a few months ago, and after researching the elevation profile of the new course, which gains about 30 feet of elevation in the first half mile before flattening out, I published an article in which I predicted the new course would be five to eight seconds slower. 

The race itself, which happened last Thursday, was held on a cool, rainy evening with slight winds.  Weather data pegs the exact conditions at 54 degrees F, light rain, and 9 mph winds at race time—certainly not conducive to the very fastest times, but not terrible.  The winner, Garrett Heath (a Minnesota native), took the win in 4:08, which was a sharp contrast to Nick Willis' blistering 3:56 course record the last time the race was held.  Heath himself was runner-up in that race with a 3:57. 

By looking just at the pro results, the new course looks substantially slower than the old one, but you could chalk this up to cautious tactics early in the race, or just a fluke from a small sample size.  To get a real answer on how much slower the new course was, and how accurate my prediction was, we'll have to do some statistical analysis.

The rest of this article will go in detail on the methods I used to compute how slow the course actually was, but if you're just looking for a quick conversion, here it is: For competitive runners, the 2015 TC 1 Mile was 13 ± 3 seconds slower than the 2013 course. A more accurate conversion is to multiply your 2015 race time by 0.9581 to get the equivalent 2013 time and multiply your time by 0.009 for the uncertainty. 

Saturday, April 25, 2015

The bone stress injury model: a new way to deal with stress fractures and stress reactions in runners

An MRI reveals a tibial stress fracture
Traditionally, overuse injuries to the bone in distance runners are divided into two distinct categories: stress reactions and stress fractures.  Runners who develop pain along one of their bones hope desperately that they have the former and not the latter, since the usual prescription for stress fracture recovery is six to eight weeks of no running whatsoever.  The usual restrictions for stress reactions depend on the doctor, but typically involve two to four weeks away from running.  Some doctors, coaches, and runners eschew the term "stress reaction" entirely because, in their view, you either have a stress fracture, or you don't—that's all there is to it.

Normally, the story unfolds something like this: a high school runner develops a sharp, aching, localized pain somewhere along a bone in his lower body.  It doesn't improve much with icing and lowered training volume, so his coach or trainer refers him to a doctor.  The doctor orders an X-ray, examines it, but sees no evidence of calcification, so he orders the runner to ease back into training, but return if pain continues.  The high schooler gives running a shot, but continues to have pain.  The doctor then orders a bone scan or an MRI, which shows bone marrow edema or increased metabolic activity at the location of pain.  This is deemed to be a stress fracture, and the runner is put in a boot, forbidden from running for six to eight weeks, and his season is effectively over.  Sound familiar?

The reason for caution with stress fractures is well-known.  If you have a stress fracture and continue to run recklessly on it, it can worsen and eventually lead to the bone splitting in two—a true fracture.  This can lead to heaps of complications and could end your running career.  There is also a category of "high risk" stress fractures that occur in particular areas like the femoral neck, the navicular, and the sesamoid bones, which are known to have a significant risk for poor healing or nonunion.1 These require even more time off and a much slower return to running.

Problems with the old model

However, doctors and physical therapists are starting to learn what coaches have already picked up on: the traditional approach to low risk stress fractures (as the vast majority are) is inadequate on a number of points.

The case for a new approach to bone injuries in runners was laid out in an exhaustive review article published in October of last year by Stuart Warden, Irene Davis, and Michael Fredericson, three extremely prolific running injury researchers.2 They propose using the term "bone stress injury" or BSI, which is intended to encompass all overuse injuries to bone that runners sustain. 

Under Warden, Davis, and Fredericson's model, bone stress injuries exist on a continuum.  On the most severe end of this spectrum are true stress fractures: a fracture line is observable on an MRI or CT scan, and there is edema (swelling) in the bone marrow and periosteum, the membrane that covers the surface of the bones.  A stress fracture is accompanied by a sharp pain or ache during weight-bearing activity that sometimes persists even when you're resting. 

The next step down the continuum of bone stress injury is the stress reaction: pain and aching during or after weight-bearing that is associated with bone marrow edema (on an MRI) or increased bone remodeling (as imaged by a bone scan), but lacks a visible fracture line. 

Further down the bone stress injury spectrum lies asymptomatic areas of bone remodeling.  As it turns out, if you were to schedule weekly MRIs for a group of high-level runners in heavy training—say, a college cross country team—you would quite often find runners developing transient areas of bone marrow or periosteal edema that would be indicative of a stress reaction, except that they have no pain associated with them, and never develop problems in the area.3 

The biology of bone remodeling

One of the core paradoxes of stress fractures and stress reactions is why they occur in fairly experienced runners.  All medical students can recite Wolff's law—bone responds to stress by becoming stronger.  So, theoretically, running more should lead to stronger bones, not stress fractures.

Thursday, April 9, 2015

Using the Tempo Trainer for pacing interval workouts on the track

The Tempo Trainer
As a high school coach, one of the toughest things to teach young runners is proper pacing.  Everyone has seen a high schooler who takes off far too fast in a mile or two-mile race, only to stagger home disappointed and out of energy at the end.  Pacing in races is obviously important, but so is pacing in workouts.  An improperly-paced interval session can ruin the intended purpose of the workout.

Take, for example, a staple high-end aerobic session: "cruise interval" kilometer repeats done at the anaerobic threshold.  A high school runner who is currently in 9:55 3200m shape might be looking to run 6x1km at around 3:30 per kilometer with a minute's rest between each.  When done properly, running each repeat at an even pace, this is a fairly relaxed workout.  However, if poorly paced, it quickly becomes a lot more challenging. 

For an experienced runner or a coach, it can seem baffling when a new runner is incapable of pacing.  Younger runners haven't developed their own internal sense of pacing yet, so they struggle to hit prescribed workout paces, even if the workout isn't inherently difficult. 

Can't you just check your watch every 200 meters? Frequent watch-checking is the most obvious solution, but this brings along a host of problems.  First, you're relying on all of the runners you are coaching to remember to bring a watch, which can be its own struggle.  Second, a watch only allows you to check cumulative times; adding up splits in your head can be a little tricky if you aren't running a mathematically convenient pace.

The proper pace for a 3:30 kilometer is 42.0 seconds per 200 meters.  What I'll often see when a group of high school runners attempts to run this pace is wild variation in the per-200m split, alternating between too fast and too slow.  So, a group might run the assigned pace of 3:30, but will do it with intermediate splits of 39 - 41 - 44 - 44 - 42.  Hardly ideal! You can take a split each 200 on your watch, but then you can't report your overall time to your coach.  Using the watch to gauge pacing can also lead to overcorrection: running a 40-second 200 to "get back on pace" by 400 meters, following a first 200m split of 44 seconds, for example. 

Discovering the Tempo Trainer

Through a combination of luck and resourcefulness, I stumbled across a more robust solution.  In the fall, I suffered a case of Achilles tendonitis which led to a few weeks of aqua-jogging in the pool to maintain my fitness.  I shared pool space with a club swimming team which occasionally used a small pacing device called the Tempo Trainer to help them set their stroke rate (much like some runners use a portable metronome to assist with setting their stride rate).  The waterproof unit was meant to be tucked inside a swimmer's swimcap and was loud enough to be heard underwater. 

It wasn't until I mentioned the Tempo Trainer to a swimmer friend of mine that I realized that it could be used for pacing interval workouts as well.  My friend remarked that she often used its pacing function so she could hear a "beep" at a prescribed interval during long repeats in the pool.  So, for example, if she wanted to swim a 100 yard repeat in 66 seconds, she'd set the Tempo Trainer to beep every 16.5 seconds, so she'd hear it each time she pushed off each wall in a 25 yard pool.  By judging whether the beep was early or late, she'd be able to tell whether she was ahead, behind, or on pace.

Hearing this reminded me of a special workout called the "Faraggiana-Gigliotti Test" that Italian running coach Renato Canova conducts on his top marathon runners.  The test involves taking blood lactate samples after a series of 2km repeats at a range of potential marathon paces to get a reasonable estimate of an athlete's current marathon fitness.  To ensure his athletes pace each two-kilometer repeat as efficiently as possible, the coach sets out cones every 25m and uses a loud beeper set to beep at the proper interval for the required pace.  As John Kellogg has pointed out, doing so requires the beeper to be placed in the center of the infield, so you don't get pacing variations due to the speed of sound as you round the track.  One central beeper also has to be loud enough to be heard from the other side of the track, and you can only use it for one workout group at a time.  Finally, unless a coach manually resets it or changes the beep interval, the athlete has no control over it. 

The Tempo Trainer circumvents all of these limitations.  It's small enough to easily be carried in your hand during a workout, and it is loud enough to be heard even while running in a group, but not so loud that everyone within a quarter-mile can hear. A large track or cross country team could use one Tempo Trainer for each workout group.  Finally, if you get sick of it, you can turn it off and toss it on the infield.  It also comes with a clip that you could use to attach it to your shorts, but I found it easier to just carry it in your hand.  After doing some research, I bought one and tested it out. 

Thursday, February 12, 2015

Is the new course for the 2015 Twin Cities 1 Mile going to be slower?

Nick Willis leads the 2013 TC 1mi

This week, Twin Cities in Motion announced that the 2015 edition of the Twin Cities 1 Mile will be run on a new course heading north on Hennepin Avenue through downtown Minneapolis, instead of the historic course down Nicollet Mall.  The motivation for this change was construction of a new light rail line that crosses the Mall, with trains that run every few minutes—far too frequent to be able to get a full wave of runners across quickly.
The old course was flat and very fast, and with its very generous prize purse, the elite wave attracted several extremely fast milers.  Because of stormy weather, the race was canceled at the last minute in 2014, but in 2013, Nick Willis set a course record of 3:56.1 in 2013 for a cool $10,000 bonus, and five other runners broke four minutes. 

A new course, but the same record

In a recent interview with Minnesota running blog Down the Backstretch, TC 1 Mile race director Jeff Decker clarified that, even though the course has changed, Willis' 3:56 (and Sara Hall's 4:30.8, run in 2011) are still considered the "event records," so to earn the $10,000 record bonus, these are still the marks a runner would need to hit. 

Which brings us to the new course.  The new route up Hennepin Avenue has no turns to mention, but it does have a noticeable uphill in the first half mile or so.  Down the Backstretch provided a handy chart comparing the elevation profile of the old and the new course.  Can we use this to predict whether the course will be faster or slower, and what kind of performance would be necessary to break a course record?

In fact, we can, as long as we make a few simplifications.  If we can make an idealized model of each course, we can compare their relative "fastness."  As you can see in the chart above, the old course fluctuates a bit, but never gains nor loses more than ten feet.  Because of this, I'm comfortable treating the old course as if it were perfectly flat, i.e. no significant differences from an idealized "fast as possible" course.

Tuesday, February 3, 2015

Is less running better for you? An in-depth look at "Dose of jogging and long-term mortality"

About once a year or so, a new scientific study comes out which makes bold claims about the harmful effects of too much exercise.  These get a lot of media attention and feed a strange sort of schadenfreude among the sedentary populace.  Meanwhile, other research that doesn't carry such contrarian views is quickly brushed aside.

It's about that time again—this week, a study published in the Journal of the American College of Cardiology made the case that infrequent, slow jogging is best for health: too much jogging, or jogging too fast, are detrimental to the point of being just as bad as sedentary life.  The news media, eager to grab onto a more attention-grabbing storyline, highlighted the article's claim that too much jogging is as bad as being sedentary.  Cue the satisfactory back-patting from the couch potatoes. 

The scientific paper in question was published by Peter Schnohr and other researchers at a number of hospitals in Denmark, as well as the University of Missouri-Kansas City.  Some other online commentators have brought up the authorship issue—one of the coauthors, James O'Keefe, is a cardiologist who strongly believes that endurance training is bad for your cardiovascular system and has authored or co-authored many of the attention-grabbing scientific papers in the past few years that argue high-volume endurance training is harmful—but here, we'll concern ourselves only with the data and its interpretation, not any accusations of bias.  If we're bringing up author bias, certainly you must include me (a proponent of and participant in high volume and high intensity training) in the discussion.  But instead of fretting about all of this, let's jump right in to looking at this article. 

The statistics of study design

By following a very large group of Danish citizens for a twelve-year period, the authors sought to investigate the effects of jogging (let's leave the "running vs. jogging" terminology debate for another day) on your risk of death from any cause.  Because it picked out a large group of healthy subjects, then followed them to observe who ended up dying before the study's conclusion, this study was a prospective study.  This design gives the study a lot more predictive power to discover associations between lifestyle and mortality (i.e. death rate), but at the cost of making the statistics harder.

The best analogy for us to understand a prospective study versus the alternative, a retrospective study, is to imagine trying to figure out what causes a running injury like IT band syndrome.  The most obvious way to investigate the causes of IT band syndrome would be to gather up a large group of runners who already have IT band syndrome, then make some measurements (like impact forces during running, or hip strength, for example) and compare these measurements to an equally-sized sample of healthy runners.  This design is retrospective, and though it's easier to find a large number of people with the condition we are interested in, you can probably see some of the problems with this.  Maybe we discover that the runners with IT band syndrome have a "hitch" in their stride when compared to the healthy runners.  Is this asymmetric stride the cause of their IT band syndrome, or is it a result of trying to avoid putting weight on the injured area? The retrospective study design is fraught with these types of problems.

A prospective study designed to investigate IT band syndrome would have to gather a large group of healthy runners, measure all of them, and then wait and see who goes on to develop IT band syndrome in a year (or any timeframe, really).  We can gather some very powerful information from this type of research, because the data grant us predictive power.  After doing our analysis, we might be able to say "runners with poor hip strength are twice as likely to get IT band syndrome," for example.  The only problem is that it's very hard to get good data in prospective studies because often, the condition you are trying to study is just not very common.  Let's say we follow 200 runners for a year, and half of them suffer an injury at some point during our study.  From other research on the frequency of running injuries, we would only expect about eight cases of IT band syndrome from our initial sample.  So, to draw useful information from prospective studies, you need to do at least one of three things:

1) Have a very large sample size
2)  Follow your study population for a very long time
3) Be comfortable inferring conclusions from small sample sizes

The same issues hold true for the Danish longevity study.  While it's measurably harder to do a retrospective study on mortality (good luck asking a dead man about his exercise habits), the prospective design is still the right choice.  To achieve usable results, however, the authors of this study had to take all three of the above steps.

Friday, January 30, 2015

52 more things I learned from a third year of weekly writing

This month marked three years since I started writing articles for investigating what the scientific literature has to say about a wide range of running-related topics, from injuries to training to peak performance on race day.  At the end of each year, I've made a list of one useful tip or interesting fact that I learned from each week's research.  Here are fifty-two more things I learned from reading scientific research this past year, one from each article.  If you want to see all of the material I've written, head on over to the blog section of RunnersConnect! Also feel free to check out the yearly lists from 2013 and from 2012.

1.  Celiac disease, which affects around one percent of the population, can cause a wide range of vague, non-specific symptoms that can interfere with your training, like joint pain, extreme fatigue, weight loss, gastrointestinal problems, and anemia.  Further, even once you've adopted a gluten-free diet, it can take a while for your body to return to normal.

2.  If you choose to eat a vegetarian or vegan diet, you're more likely to have iron-deficiency anemia, amenorrhea (if you are a woman), and insufficiently vitamin B12 levels.  Though it's very possible to have a complete diet as a vegetarian or vegan, you need to take extra care to ensure you get enough protein, vitamin D, and iron, and you should probably take a vitamin B12 supplement or eat foods that are fortified with it.

3.  Scientific findings can run contrary to your own experiences.  The research says it's okay to run when you have a cold, that the speed of your daily runs does not affect your injury risk, and that it's okay to do some running on an injured area, as long as you monitor your pain and stop before it's over 5/10 on the pain scale.  In my own training, I can't get away with any of this! There might be subtle reasons why the findings from one study don't apply to your own experiences.

4.  The faster you run, the greater the proportion of your energy that comes from carbohydrates.  This has some major implications when it comes to running out of fuel in the marathon.  The people most at-risk for "hitting the wall" before the finish of a marathon are very fit runners who can run at a high percentage of their VO2 max, and heavier, overweight runners—especially if their extra weight is not in their legs.

5.  When planning out a fueling strategy for a marathon, you should generally shoot for taking in 60 grams of carbs per hour of running.  If you have had major problems with hitting the wall, you may consider increasing your carb intake to 90 grams per hour.  However, if you've had gastrointestinal problems from trying to refuel, you might want to cut this down to 45 or 30 grams per hour. 

6.  Gels, sports drinks, and energy chews are all equally valid choices for refueling during a long race.  None of them offer a distinct physiological advantage, so feel free to choose whichever suits you best. 

7.  Electrolytes aren't all that important for endurance events.  There's no good evidence that you need to replace the salt you lose in your sweat—it appears that your body intentionally modulates the amount of salt you lose in your sweat to keep the concentration of electrolytes in your blood constant, so there's no need for salt tablets or super-salty sports drinks.

8.  There's no magic formula for carbo-loading.  All you need to do is increase your carbohydrate intake by 50-75% over the last few days leading up to a long race (over 90 minutes), and you don't need to do a "depletion period" prior to it to get the benefits of carbo-loading.

9.  In a marathon, elite Canadian runners consume between 16 and 26 fluid ounces of liquids per hour of running and about 50-75 grams of carbs per hour.  Elites use a combination of gels, solids, and sports drinks according to personal preferences.

10.  When runners collapse after finishing a race, it's usually (though not always) from a sudden drop in blood pressure that's triggered when you stop running.  After laying down for a few minutes and elevating their legs, they'll be fine.  When runners collapse during a race, however, it's much more likely that they're having a medical emergency like hyponatremia or sudden cardiac arrest. 

11.  Some research suggests that taking vitamin C before and after completing an ultramarathon can decrease your risk of getting sick.  Over half of the finishers of a 90km ultramarathon in one study came down with a cold in the weeks following the race!

12.  However, try not to load up on antioxidant supplements in general.  They can inhibit your body's adaptation to exercise: oxidative stress is a big part of improvement! Fruits and vegetables are probably okay, though.

Monday, January 19, 2015

Video: Testing the science behind Kenzen's Echo H2 Sensor

A few days ago I came across this Indiegogo crowdfunding campaign for a new wearable device called the Echo H2 Sensor which claims it can detect your glucose levels, hydration status, and lactate levels in real-time during exercise by analyzing your sweat.  I set out to do some research on whether there's any science behind their claims.

If you've got a question that you'd like answered in a future video or blog post, leave a comment here or on the video page, or drop me a line at the Contact Me page!

Saturday, January 3, 2015

Video: Modifying a pair of track spikes to prevent ball of foot pain

It's time to get back in the habit of uploading more content! In this video, I show how I use a Dremel rotary tool with a sanding bit to shave away the plastic spike holder under the ball of the foot on a pair of Saucony track spikes.  The ball of my foot carries a lot more of my weight than the rest of my forefoot, but this isn't usually a problem as long as I'm in a shoe with a soft midsole.  Track spikes, however, can cause some problems, particularly when there is a spike holder sticking out immediately below the ball of my foot.  This excessive pressure can cause a lot of irritation in my foot, so something I often have to do when I get a new pair of track spikes is grind away anything that sticks out in that area.  This short video demonstrates how I go about doing that.

If you've got a question that you'd like answered in a future video or blog post, leave a comment here or on the video page, or drop me a line at the Contact Me page!