Wednesday, December 11, 2013

Ask Running Writings Episode 1: Introduction & Stride Frequency

I'm happy to announce the launch of my YouTube channel! Check out YouTube.com/RunningWritings for my new series, Ask Running Writings.  This show will answer questions and explain popular or misunderstood concepts about training, racing, running injuries, and more! My first video explains some of the science behind increasing your stride frequency and how it can help prevent injuries.  It also includes some advice from a coaching perspective on what type of stride frequencies you can expect to see in competitive distance athletes running at an easy pace, and how to go about increasing your stride frequency if yours is too low.



If you've got a question that you'd like answered on a future episode of Ask Running Writings, leave a comment on the video page or drop me a line at the Contact Me page!

Tuesday, November 19, 2013

Achilles tendonitis in runners: A degenerative overuse injury best treated with eccentric heel drops


Introduction

Achilles tendonitis is an extremely common injury, not just in running but in many sports.  The severity of overuse injuries to the Achilles tendon can range from dull soreness that barely impacts your ability to run or play sports to chronic, debilitating pain that can last for months or years.  Fortunately, due to its high incidence in athletes, Achilles tendonitis is a fairly well-studied injury. 

The majority of Achilles tendonitis cases occur at the midpoint of the Achilles, a few inches above the heel.  But a minority of cases—between 20 and 24%, according to a few studies1, 2—occur where the Achilles tendon flattens out and inserts at the ankle.  This is called insertional Achilles tendonitis.  While the majority of studies focus on midpoint Achilles tendonitis, and as such it is the better-understood variant, there is nevertheless a good deal that can be learned about insertional Achilles tendonitis as well.  This article deals specifically with midpoint Achilles tendonitis; if you are interested in insertional Achilles tendonitis, a detailed follow-up article is in the works, or you can read this article on insertional Achilles tendonitis that accompanied the original Achilles tendonitis post.  Unless otherwise qualified in this article, "Achilles tendonitis" will refer specifically to midpoint Achilles overuse injury.

Terminology

While "tendonitis" is by far the most common term used to refer to overuse injury to the Achilles tendon, it is not a strictly accurate term.  The suffix "-itis" implies that the root cause or main feature of some condition is inflammation—as is the case in appendicitis, gingavitis, and so on.  But, as we'll see in the research papers reviewed below, inflammation of the Achilles tendon or its surrounding tissues is not a common finding in athletes with overuse injuries to the Achilles.  Rather, their pain is caused by real, physical damage to and degradation of the small fibers that make up the Achilles tendon.  Because of this, some doctors and researchers advocate renaming the injury "Achilles tendonosis" or "Achilles tendinopathy" to make it clear that degeneration of the tendon fibers is the root of the problem.  Despite my support for this idea, I will use "tendonitis" in this article, as it is still the most common term for the injury. 

In older literature, you might also see phrases like "Achilles tenosyndovitis" or "Achilles peritendinitis," terms which indicates that the source of the problem lies in the tissue that surrounds the Achilles tendon proper.  Research on this is limited, so it is not clear to what extent (if any) injury to the sheath surrounding the Achilles plays a role in Achilles tendonitis. 

Thursday, July 4, 2013

Developing race conversion factors for outdoor track races



Now that the outdoor track season has finished up here in Minnesota, both for high school and college athletes, I decided to do a follow-up on my article about developing race time conversions.  Several months ago, I posted a tutorial on how to use a spreadsheet program (like Excel) to do linear regression on performance lists in order to develop your own conversions between race distances.  This is a nice exercise in statistics, but it can be very useful if you need a conversion for an uncommon race that's unique to your state or collegiate conference.  It allows you to answer the question of "what kind of 1500m performance is necessary for a 15:00 5k?," but by doing the statistics yourself, you can also get a good idea of the range of performances over and under a particular race distance, or, in other words, you can see how reliable a conversion is.

Much like last time, I used the performance lists from the 2013 Minnesota Intercollegiate Athletics Conference (MIAC) outdoor track season.  For comparison, I also ran some statistics on the Minnesota State High School League's honor roll list.  Unfortunately, since the honor roll only accepts performances above a certain threshold, our statistical power to predict race performances is significantly lower, because we do not get as wide of a range in performance. 

For the impatient, the most salient results are summarized in the table below.  You can use these multiplicative conversions to use one performance to predict another over a different race distance.  Since they are simple multiplications, you can also stack them to convert, say, a 1500 to a 10k by first multiplying by the 1500m to 5k conversion, then multiplying again by the 5k to 10k conversion.  Be aware that stacking conversions will mean they are less reliable.


Some conversion (e.g. 800m to 1600m) are missing due to a lack of complete data—see below for more

For the more mathematically-inclined, we'll go further in-depth on analyzing the results.  For every race conversion from 400m up, I performed linear regression on the race performances of people who had recorded performances in both events.  So, for the men's 400m to 800m conversion, I found the linear equation (of the form y = a x + b) that best fit the data.  I also calculated the r2 value, or the coefficient of determination.  This factor can be pictured as the percent of the variance in longer race performance (over, say, 800m) that is predicted by your performance over the shorter distance (e.g. 400m). 

The full results are presented in the table below.



If you read my first post on using statistics to analyze performance lists, you'll remember that we found race conversions to be the most reliable when comparing races that are physiologically similar, meaning that they rely on the various energy systems of the body to similar extents.  Because of the way the body breaks down energy expenditure in middle and long-distance races, this leads to some curious results in our statistics.  Converting from 5k to 10k, for example, is significantly more reliable than converting a 400 to an 800.  In the outdoor track times, I also found that wider ranges in times generally resulted in more reliable conversions.  The women's 5k to 10k conversion, for example, is much more reliable than the men's conversion.  This might just be a statistical artifact, given that the data from the women was distributed over a broader range of times, though it is also possible that women do truly run more "predictable" 10ks when considering their 5k race performance.

When analyzing the gains when using the "full" linear regression model (instead of forcing the intercept of the equation to occur at zero, allowing for simple multiplication conversions), the only case in which there was a significant gain in predictability was in the men's 5k to 10k conversion, where using the full linear model resulted in an absolute gain of 8.7% in predictive power—the full linear model explains 78.0% of the variance in 10k performance based on 5k time, while the simple model explains only 69.3%.  The women's 1500m to 5k conversion showed a 3.0% gain, but I'm comfortable calling this insignificant.    

Of most interest to me was the particularly poor results in the men's 400m to 800m conversion.  Using the performance-list recorded times, there is almost no predictive power in knowing a particular runner's 400m time.  Only seven percent of the variability in 800m times could be explained by 400m time, and when forcing a simple multiplication factor, the predictive power is zero (technically negative, due to the way r2 is calculated).  This could mean one of two thing—either our data is incomplete, or there really is a very weak relationship between 400m time and 800m time.  One reason our data could be bad is because relatively few 800m runners actually run the open 400m often during outdoor track.  With plenty of opportunities to run a 400 at the end of a meet in the 4x4, it doesn't make a whole lot of sense to get tired before your prime event (the 800) in an open 400.  Strangely though, the women did not suffer from this same problem. 

When looking at a graph, it appears that many 800m runners are able to run quite fast (under 2:00) with open 400s ranging from 50.0 to almost 55 seconds.  I'd have to look at more data—probably lists of season bests which included relay splits—to determine whether this is a statistical artifact or a real physiological phenomenon. 

Because of the relative difficulty of getting onto the MSHSL high school performance lists, our predictive power in high school races is much lower.  There weren't even enough people in both the 400 and 800 lists to justify running analysis, and the 800 to 1600 conversions are woefully unhelpful.  The 1600 to 3200 conversion is respectable, at least for the boys.  Performance among girls in the 3200 appears to be much more variable than it is for boys; the reasons for this are not clear.  It could have to do with more variance in training, or it could be another statistical artifact.


So, aside from developing some helpful conversion factors, what have we learned? For one, open 400 performance doesn't have a very strong relationship with 800m performance, at least for men.  Second, a simple multiplication conversion is almost as good as a full linear regression model for most race conversions, the only standout being converting a men's 5k to a 10k.  And finally, as we saw with indoor races, conversions work best between races that are physiologically similar; even if a race is very close in distance to another (like the 400m and 800m), if they rely on differing energy systems, our conversions will be much less successful!

Thursday, May 16, 2013

Modern Training and Physiology for Middle and Long-Distance Runners



I am very happy to announce the publication of my first book, Modern Training and Physiology for Middle and Long-Distance Runners.  Followers have probably noticed a steep drop-off in new content here on Running Writings in the past few months; this is because most of my energy has gone into writing, reviewing, and editing this book! Now, after all of that, it is finally ready for release.  Modern Training is a spiritual successor to Basic Training Principles, the free booklet I released last year for young runners.  It is a comprehensive guide to formulating a training structure and, more importantly, a training philosophy that ensures improvement and development over the long term. 

As the title suggests, Modern Training and Physiology educates the reader on the most important developments in exercise physiology and training theory in the past fifty years and covers how to apply these principles to your own running.  Among the topics covered are:

  • Lactate, acidosis, and energy systems
  • Physiological adaptations to training
  • Race-specific workouts
  • Mileage levels
  • Proper recovery
  • Mental Training
  • Improving running economy
  • Structuring your running season
  • Nutrition and body size
And much more!

At 96 pages, this book requires no background in training literature or physiology.  It has everything a young runner needs to get on the right track for long-term development in high school and beyond.  But make no mistake—there's far more in Modern Training than the same platitudes about running that you've heard before, and it offers new perspectives even for veteran coaches.

Readers of this blog will find the same down-to-earth, straightforward tone in Modern Training that you see on Running Writings, and the material presented is solidly rooted in exercise physiology, biomechanics, and modern coaching theories.  There are also useful reference charts, recommended reading, and even a glossary! If you are training to run anything from the 800m to the 10k, or if you coach runners who do, you'll get concrete examples of workouts, mileage, and ancillary training, and even marathoners, triathletes, and trail runners can get a new perspective on how they approach their own philosophy of training.

Modern Training and Physiology is available on Amazon.com for $8.99 RIGHT NOW! If you live in Minnesota and can manage to track me down in person, I'll be able to get you a discount as well.  If you really want to help me out, post a review on Amazon after you've read it. 

If you are a book retailer or running store and would like to sell copies of my book, send me an email and I will sell and ship them directly to you for a substantial discount.  Likewise, coaches who would like to order a large number of copies (10 or more) for their athletes or their coaching staff can also get the retailer's discount—just send me a message and I'll be able to ship them directly to you!

Finally, I'd like to thank all of the friends, family, coaches, teammates, and fellow runners who supported my writing and my studies over the years, and I would also like to extend my gratitude to the individuals who helped me get photos, data, and graphs for use in the book.  And of course I would like to thank all of you, the readers of Running Writings, who gave me the platform to launch my writing career!

For readers in other countries, here are direct links to your local Amazon sites:

UK - Order Here

Italy - Order Here

Spain - Order Here

France - Order Here (currently unavailable for unknown reasons)

Germany - Order Here

 



Thursday, April 25, 2013

Brief thoughts: Sunlight, vitamin D, and seasonal variability in performance



I was reading some scientific papers on nutrition and bone health which led my attention off in an interesting direction.  The topic I had originally been researching was the role of calcium in maintaining bone health (spoiler: calcium is important!), but what really sparked my interest was the emerging science of vitamin D.  Vitamin D is something I've long thought of as just an adjunct to calcium intake; much like vitamin C boosts iron absorption, so too does vitamin D boost calcium absorption.  But as it turns out, there is much more to vitamin D.  For one, it's really more of a hormone than a nutrient, and strictly speaking it's not a "nutrient" at all—even an extremely healthy and nutritious diet hardly contains any vitamin D at all.  Most of the vitamin D in your body is synthesized by exposure to sunlight. 

With some interesting chemistry, your skin is able to capture some of the energy from the sun's ultraviolet light, using it to kick-start the reaction that synthesizes vitamin D from a cholesterol-like precursor.  Since this is the primary source of vitamin D for most people, blood levels of vitamin D tend to vary by season, peaking in the late summer and dropping sharply by mid-fall.  Additionally, people who spend a lot of time indoors (including indoor athletes like gymnasts), live in northern climates (like Minnesota, my home state), and who have dark skin are less likely to be able to synthesize enough vitamin D through their day-to-day sun exposure.

Thursday, March 14, 2013

"Show me where it hurts"

While my Injury Series articles are among the most popular on my blog, they are spread out over several pages of posts on my blog, and a lot of readers aren't sure which injuries I've covered and when.  I sometimes get requests for injuries I've already written about! To solve this problem, I've created a home page for the Injury Series, which you can see along the tabs at the top of every page.  In addition, I've created an "injury map"—an easy reference so you can connect what hurts with the proper article! You'll find it on the Injury Series page, but I've also reproduced it below.  Enjoy!




midpoint achilles tendonitis
insertional achilles tendonitis
patellar tendonitis
medial tibial stress syndrome
plantar fasciitis
iliotibial band syndrome
patellofemoral pain syndrome
tibial stress fracture
home
Image Map





Sunday, March 3, 2013

Moving on to new adventures



For the past six months, I've been living in Virginia and working for a start-up called the Runner's Health and Performance Institute.  Its goal was to become the go-to place for runners with injuries and performance issues in Northern Virginia.  Unfortunately, I recently got the news that, because of some unforeseen challenges in gathering the resources necessary for the business, the RUNHAPI project is not going forward.  While I'm disappointed that the business has to shut down, I'm also looking forward to new opportunities in the running community.  As of tomorrow, I'll be moving back to Minnesota—hopefully in time to help out at a local high school for the spring track season! I also have some big things coming up for Running Writings, which I'm very excited about.  My next booklet (or book, depending on where you draw the line) is one proof-read away from release, so look for a big announcement on that in the next few weeks.  I'm also planning to revamp some of the older Injury Series articles, upgrading the citations and including new information on some great research papers that have come out in the last few years.  I'll also be working on ways to make the information in the Injury Series available in a variety of formats—a book, posters, or maybe smaller summary sheets for people who don't want to read 5-10,000 words on their injury.  If you have anything you'd like me to write about, leave a comment below and I'll look into it.

Outside of that, I'm thinking about what direction I'll go in the next few years.  There is coaching, writing, graduate school and research, or who knows what else! If you've got any ideas (or better, any opportunities!) definitely drop me a line on the Contact Me page; I'd love to talk with you! Finally, I ought to apologize for the lack of content recently, which to some extent is a result of having to sort out how and when I'll be moving back to MN and so on.  Look forward to more running writing in the future! 


Wednesday, February 13, 2013

Brief thoughts: Calculating percentages of race pace


A few days ago, I received an email from my high school coach asking me about the "correct" way to calculate percentages of a given pace.  This is a question that I am asked fairly frequently, and the answer has a few interesting angles, so I have decided to make a post about the details.

Many different training programs are predicated on doing workouts, easy runs, and interval sessions at various percentages of a particular pace, whether this is race pace or threshold pace or VO2 max pace.  But if you ask a group of people how to calculate, say, 85% of 5:00 mile pace, you'll get two different answers.  The first camp will say, "Simple, just multiply 5:00 per mile by  1.15, which gives you 5:45 per mile."  The second will say, "No, you have to divide 5:00 by 0.85, which gives you 5:53."  Who is correct?

In some sense, they are both correct.  To break down what each of these particular strategies actually mean, mathematically speaking, it helps to compare and contrast the result for a variety of percentages.  So, sticking with our example of 5:00 mile pace, let's do the math on a few various paces, both faster and slower than 5min-miles.  To make things simple, let's call one variant—85% = 5 x 1.15— the "multiplication method" and the other—85% = 5 / 0.85— the "division method."


Monday, February 4, 2013

Injury Series: Plantar fasciitis in runners as a degenerative overuse injury

Plantar fasciitis is a vexing, persistent, and fairly common injury to the plantar fascia, the thick, fibrous band that runs along the bottom of your foot.  While it accounts for around  8% of running injuries,1 it is also quite common in the general population.2  Unlike many running injuries, it is slightly biased towards men; one study found that, of 158 runners diagnosed with plantar fasciitis at a sports medicine clinic, 54% were men.1  Plantar fasciitis is by far the most common cause of "heel pain," and a quick internet search for that term will turn up a slew of podiatry websites which specialize in treating plantar fasciitis, both in athletes and in sedentary people.  While not technically correct, plantar fasciitis is often referred to as having "heel spurs."  Ironically, despite its commonality in both active and inactive people, and despite the fact that it makes up a huge percentage of the patients at podiatry offices across the country, plantar fasciitis is a poorly-understood injury with no solid slam-dunk treatment or even a firm theoretical underpinning of the mechanism of injury.  Regardless, we'll dive into the wealth of research on it to learn what we can and inform our treatment and prevention approach. 

Terminology
As is often the case, there are some terms we need to clarify before we go into the bulk of the article.  Plantar fasciitis is another unfortunately named injury, as the -itis suffix implies an inflammatory cause, which we'll soon see is not the case.  The plantar fascia is also sometimes referred to as the plantar aponeurosis; medically speaking, an aponeurosis is a flat band of tissue that closely resembles a tendon and connects either bone or muscle to each other, while a fascia is a band of connective tissue that encapsulates muscles.  Because "plantar fascia" is the more common term, and because the injury is still most often referred to as "plantar fasciitis," those are the terms I'll be using in this article.  While "heel pain" and "heel spurs" are commonly used to refer to plantar fasciitis, neither are correct: while it is indeed the most common cause of heel pain, there are other injuries, like a calcaneal stress fracture, that can cause pain at the heel.  And a heel spur—a small bony growth extending from the heel bone along the plantar fascia—is neither a definitive cause nor indicator of plantar fasciitis.3


Anatomy and function
The plantar fascia as a whole is comprised of several bands of connective tissue that run along the sole of the foot, anchoring the metatarsal heads to the calcaneus (the heel bone).  While there are several separate bands, the most important is the central aponeurtoic band.  It runs from the medial side of the heelbone, fanning out as it attaches to each of the five metatarsal heads.  At the heel, the center band of the plantar fascia is thick and has a triangular cross-section.  The central band handles the bulk of the strain on the plantar fascia, and as such is the part most susceptible to injury.  Some sources describe the entire collection of plantar bands as the "plantar fascia," while others refer to it as the "plantar aponeurosis" and the central band as the "plantar fascia."

On a microscopic level, the plantar fascia is much like other tendons and ligaments of the body: small, wavy proteins called collagen fibers make up the structure of the fascia, giving it strength and stiffness.  The plantar fascia is stronger and stiffer than the small tendons of the body, though it is weaker and more stretchy than the patellar or Achilles tendons, which handle high loads at the knee and ankle, respectively.  With a stiffness of about 200 N/mm,4 the plantar fascia isn't something you could "stretch" like a rubber band, but it's also springy enough to store and release energy elastically during the gait cycle.5
Microscopic image of a healthy plantar fascia.  From Lemont et al.
 The plantar fascia's main function seems to be supporting the arch of the foot during standing, walking, and running.  It has been likened to a "tie-bar" which prevents the arch from flattening, though it is not the only contributor to arch stiffness.  Even when the plantar fascia is severed, the arch retains 65% of its stiffness in static stance—the rest of the structural integrity being associated with the joint capsules and bone geometry of the foot.6, 7  
The plantar fascia acts like a tie bar, helping to support the arch of the foot when it is loaded.

Saturday, January 19, 2013

What should be in a runner's injury self-treatment kit?

As much as I like scientifically validated treatments for injury, I think there's a lot to be gained from "road wisdom" treatments for running injuries.  Over the years, an experienced runner picks up or stumbles upon many useful remedies for aches, pains, and injuries.  You probably have a shoe box or plastic container with the assorted treatment aids you've amassed over the years, from doctors, physical therapists, or running stores.  There's also a veritable army of online sellers who are looking to sell devices to "cure" common running injuries (most are worthless).  A lot of these road wisdom treatments involve special gadgets or materials, so I'd like to share what's in my own personal "injury treatment kit." I will also show some things I have not found to be particularly helpful, and a few items that I recommend but don't currently have.  You'll have to excuse the pictures from my sub-par camera.




A.  Rope for stretching (~10' long)
I picked this up at the local hardware store for a few dollars.  You can find nice quality rope for well under a dollar per foot.  The length might seem long, but it's actually necessary if you want to do hamstring stretching while laying on your back.  If you're into Active Isolated Stretching, having a stretching rope is a necessity.  Use a flame to fuse the ends so it doesn't fray.

B.  Elastic theraband for exercises

I have a lot of these laying around from visits to PT offices.  They come in various stretchinesses, and you can order them online for not too much money.  There are a few good exercises for your hips, knees, and ankles that require a theraband, so it's a good investment.  if you can, get a thicker one, as they are less prone to breaking—thin ones seem to have a tendency to get brittle and snap.

C.  Rolling tools: Tiger tail, golf ball, Rubz foot ball, tennis ball, lacrosse ball

There are a lot of theories on how soft tissue is involved in injuries, and a lot of these—like trigger point theory—purport to be a cure-all.  While I think these explanations are off the mark, I have found rolling to be pretty effective with soft tissue injuries.  The various "balls" are good for different parts of the body: the golf ball and Rubz ball for the arch of your foot, and the tennis ball and lacrosse ball for the hips, hamstrings, and especially the glutes.  There are a few variants of rubber textured foot balls; I highly recommend you get one for your arches. They are the right stiffness, and they don't slide away on hard surfaces like golf balls do.  You can pick them up online or at some specialty running stores.

Golf, tennis, and lacrosse balls can be found in reasonably abundant quantities nearby parks where the respective sports are played.  If you run on a golf course or do drills on a high school practice field, you're bound to come across some lost balls that would have ended up getting sheared apart by a lawnmower.

The "Tiger Tail" is a rip-off of "The Stick," the common muscle rolling tool.  I personally think the tiger tail  has marginally sturdier construction than The Stick, and if it does break, there won't be two dozen plastic rollers flying everywhere (as happened to one of my college roommates).  Either of the two are pretty great for calves and quads.  They are really good for other parts of your body too, but you'll need someone else to actually do the rolling. 


Saturday, January 12, 2013

52 lessons learned from a year of weekly writing

As some of you probably know, I've been writing weekly articles for Runners Connect for the past year.  Runners Connect is a great coaching and training website run by Jeff Gaudette, a DI All-American and runner for the Hansons-Brooks Distance Project.  This most recent article marked my 52nd weekly post at Runner's Connect, so I thought I'd write up a post looking back on the past year of my writing there to 1) give a big shout-out to Jeff Gaudette and all of the folks over there and 2) give a quick glimpse at what the scientific literature has to say about a vast range of topics.  For the full articles, head over to Runners Connect.  So, here are 52 useful lessons I've learned in the last year, one from each of my posts:

1.    Picking the right shoe isn't a matter of pronation control or arch support; it's chiefly a matter of what feels comfortable on your foot

2.    Increasing your stride frequency by about 10% appears to reduce loading on the hip and knee (though not the ankle)

3.    When it comes to "core strength" for runners, strength in the hips and glutes is most important for preventing injury

4.    Don't feel too bad about skimping on strength for the "traditional" core of the abdomen and back, because there's very little evidence that they matter much for preventing injury (Note: some recent reading I've been doing has discussed a connection between abdominal weakness and hamstring injuries—expect to see an injury series article on that in a few weeks)

5.    Weakness and dysfunction in a thin, wide muscle called the transverse abdominus, which runs underneath the "normal" ab muscles, may be linked to low back and groin problems.

6.     Drinking a cup of coffee (or taking a 200mg caffeine tablet) an hour before a race or workout will give you a small but notable performance boost (and you don't have to abstain from caffeine in the preceding days either!).

7.    Medical-grade compression socks—which are not the same thing as the Nike compressionwear or Oxysocks you'd find at most running stores—might boost performance by a smidge, but they seem to be better-suited for reducing soreness after a workout.

8.    Of all of the visits to the medical tent at a big-city marathon, over 20% are related to skin issues like blistering and chafing! Protect your skin with technical gear (socks, tights, etc) to keep your skin dry, petroleum jelly or another lubricant, and by wearing shoes that you've gotten used to.

9.    Once you are "over the hill," you don't slow down quite as much as you might think: Master's runners slow by about 1-2 seconds per mile per year for races from 10-15km, and 4-6 seconds per mile per year in the marathon.  Women also close the gap between male runners as they age.