Tag: stress fracture

Overall Athleticism & Risk of Injury

Will Improving Your Overall Athleticism Reduce Your Risk of Stress Fractures?

Guest blog by John Davis (RunnersConnect)

Most runners know somebody whose training or racing ambitions have been sidelined because of an injury caused by another sport.  Whether it’s a torn ACL from playing a pick-up game of soccer or a sprained ankle from a rec basketball league, “other sports” have a reputation for causing trouble when runners try their hand at them.

Traditionally, many runners are uncoordinated and unskilled at ball sports, so they tend to avoid them. Moreover, not only do runners perform poorly, they also often get hurt while doing so.

But some fascinating studies published in the past few years are indicating that this might be the wrong way to look at ball sports and general athleticism in relation to running.  Instead of merely causing injuries and soreness, participating in ball sports might confer a protective effect against some injuries because of the adaptability of your body.  We’ll take a look at these studies to figure out exactly what’s going on.

Running, ball sport, and bone strength

The first among these studies was published in 2000 by a group of researchers led by Charles Milgrom in Israel who were evaluating risk factors for military recruits who would develop stress fractures.

In a series of studies, the researchers looked at the effects of pre-boot camp activity levels on stress fracture risk in Israeli military recruits.  The recruits were surveyed on their activity levels, then followed during their basic training.  Surprisingly (and in contrast to some other military studies), being a runner did not confer a significant protective effect against stress fractures during military service. However, recruits who had played ball sports (typically basketball for the recruits in this study) for at least two years before military service suffered significantly fewer stress fractures than those who did not.

In a follow-up study, the same research group measured the strain on the tibia bone during walking, running, and basketball, finding that the peak stress on the bone was up to 50% higher during a basketball game when compared to running.  The researchers surmised that regular exposure to these higher stresses in the years before the ball-sport athletes became military recruits caused them to develop stronger and more robust bones, and hence more resistance to stress fractures.

Another study examining runners, ball-sport players, and bone strength was published in 2007 by Michael Fredericson and others at Stanford University.  Using a sample of 15 elite male soccer players, 15 elite male runners, and 15 sedentary men, Fredericson et al. used an x-ray machine to measure the subjects’ bone density at several locations in their skeleton.

Though the runners hand stronger bones than the sedentary subjects at places which are directly loaded on impact, like the heel bone, they are outclassed by soccer players, who have stronger bones everywhere as measured by bone density: whole-body, hip, leg, spine, and heel bone.   This is probably because of the dynamic nature of playing a ball sport like soccer: unlike the simplicity in running, ball sport athletes make a huge range of different cutting and turning motions on a regular basis, putting a wide variety of stresses on their skeleton.  Compared to ball sports, runners, by contrast, put moderate but repetitive stresses on their bones, which don’t result in as robust of skeletal strength overall.

Do ball sports help protect against stress fractures?

The last question to address is whether experience playing ball sports actually grants a protective effect from stress fractures in runners.  Fortunately, this exact concern was addressed in a large study of elite track and field athletes at the 2003 USATF national track championships, held at Stanford University.

Michael Fredericson, Jessica Ngo, and Kristin Cobb issued a one-page questionnaire to 156 female and 118 male distance runners competing at USATF nationals.  The athletes were asked about their sports histories and any stress fractures they had suffered.  After collecting the surveys, Fredericson, Ngo, and Cobb found that runners who had formerly been ball sport athletes had a significantly lower risk of suffering stress fractures.

For both men and women, each year of playing ball sports resulted in a 13% lower incidence of stress fractures.

Women, however, had one caveat: this protective effect only applied if they had normal menstrual periods; women with amenorrhea, which disturbs bone growth, had no protective effect from playing a ball sport like basketball or soccer.

Like with the two previous studies, the authors hypothesized that the diverse stresses associated with dynamic sports like soccer and basketball led to “greater and more symmetrically distributed bone mass,” which resulted in resistance to stress fractures.

Now, there’s still no research on whether playing ball sports while you’re also doing running training will grant any protective effects against injury, and as mentioned earlier, ball sports are far from innocuous.  Soccer and basketball players suffer a lot more ankle and knee sprains than runners do, for example.  But perhaps it is time to start thinking more seriously about the importance of general athleticism in running.

When you spend an hour a day or more running in mostly a straight line, you’re bound to develop some deficiencies when it comes to lateral or diagonal movement, as well as sharp accelerations and large stresses on your bones. 

Incorporating some agility drills or strength work into your running routine might be one way to address this; indeed, many elite runners already do strength and conditioning work that involves lateral shuffling, hurdle drills, medicine ball work, plyometric jumps, and diagonal running and cutting, all of which are similar to the types of stress involved with playing a ball sport.

Given what we’ve learned above, this type of ancillary training is likely to benefit your body’s overall structural integrity, hopefully leading to protection against stress fractures and possibly other overuse injuries too.

Get more great injury prevention advice from John Davis (plus other great training & maintenance tips from Jeff Gaudette & Co) on the RunnersConnect blog.

Choosing the Right Running Shoes

A Look at How Trainers Affect Training and Running Performance

Guest blog by Matt PhillipsRunnersConnect

running shoesFollowing last week’s article “Foot Types & Foot Wear,” I have had quite a few runners ask me the same question, with words to the effect of: “Ok, if the whole overpronation shoe model thing has no evidence, what the hell do I run in!?”

A very good question! But first things first…

Why do we need running shoes at all?

Relax, I’m not going to start preaching about barefoot running (although I’m not going to dismiss it either). But in order to discuss how we decide which trainers are suitable for us, it is useful to re-evaluate exactly what we are buying them for.

With that in mind, over the last couple of days I have been asking the runners I meet what they are looking for when they buy trainers. Collectively, the majority of them produced the following three reasons: protection,supportcushioning.

Protection

If by protection we are referring to avoiding glass & syringes, then wearing something on our feet obviously makes sense. This may well be the main contributing factor as to why, at least in my experience, it is rare to see runners training or racing in no shoes on at all.

Many of us could probably find less hazardous routes on which to entertain the theoretical benefits of barefoot running, but until clearer evidence supports such theories, most of us will probably pass.  However, if we’re talking about protection from running on hard surfaces then we are essentially looking at cushioning (more on that shortly).

Support

By support, most people are referring to stopping the medial arch of the foot “collapsing,” which brings us back to the whole supination/neutral/pronation paradigm used by most running shops to prescribe you a “suitable” trainer after watching you walk or run for a couple of minutes (or in some cases just standing you on a pressure pad, which in itself has no connection to how your foot acts whilst running). I am sure you are already familiar with the process:

  • If the arch of your supporting foot drops “too much” you are labelled an “overpronator” and assigned a motion-control shoe that will in theory reduce the “overpronation”.
  • If your arch does not drop “enough”, you are said to be an underpronator (or supinator), and assigned a flexible, cushioned shoe to absorb some of the shock that underpronator is said to cause.
  • If you are somewhere in the middle, you are said to have normal pronation and are recommended a “neutral” shoe that in theory provides just the right amount of stability and cushioning.

As we saw last week, this model is heavily flawed and unsupported to date by any evidence. It is important not to let fear of injury or promises of recovery persuade you to be herded into one of the three pens (motion control, stability or neutral) however persuasive the sheepdog/sales person may be!

Cushioning

If you regularly run on hard surfaces like pavements, tracks and treadmills, you would think cushioning makes sense. Running shops can be very quick to stress this point if they “see” you as a heel striker. And yet, studies show (Scott, 1990) that peak loads at typical sites of injury for runners (Achilles, knees, etc.) actually occur during midstance (when your bodyweight passes over the supporting leg) and toe off (when your back leg pushes away from the ground).

These studies suggest that impact force at heel contact has no effect on the peak force seen at typical injury sites.

There is also growing evidence that when faced with higher impact forces from a harder running surface, your body makes natural adjustments to deal with the change in impact force – changes in joint stiffness, changes in the way the foot strikes the ground, and also via a concept called “muscle tuning” (pre-activation of muscles prior to impact).

Based on information received visually and from the previous foot strike, the body adjusts how strongly the muscles in your leg contract before the foot hits the ground again. Imagine jumping on a trampoline – your legs naturally stiffen in preparation for the soft landing.

Now imagine yourself jumping onto concrete – your legs naturally become less stiff in preparation for the hard landing. This natural adjustment is the result of sensory feedback from not only the eyes but also from the feet. In other words, the theory is that sensory feedback from the feet following one foot strike helps prepares the body for the next foot strike. If this is indeed the case, could excessive cushioning at the bottom of a trainer inhibit this natural sensory feedback?

Cushioning & injury prevention

The role that impact actually plays in running injuries is not at all clear. Studies by two highly respected biomechanics researchers, Dr. Irene Davis (Director of the Running Injury Lab, University of Delaware) and Dr. Benno Nigg (Co-Director of the Human Performance Laboratory, University of Calgary) have produced contrasting results.

Whilst Dr. Davis’ research links high impact loading rates with plantar fasciitis and tibia stress fractures, Dr. Nigg has found that overall injury rates are slightly lower among runners with high impact loading rates.

One possible interpretation of the above is that leg stiffness, as we considered earlier, is an important factor with certain injuries. Dr. Davis’ research linked runners who had suffered tibia stress fractures with higher impact forces and higher leg stiffness.

If tibia stress fractures are a consequence of high leg stiffness (for which I hasten to add there is as yet no evidence) then maybe runners susceptible to them should try wearing a less cushioned shoe and run on harder surfaces.

Just as we saw in our “landing on concrete” example earlier, in preparation for the harder surface, the body will reduce leg stiffness, which if the theory is correct could reduce susceptibility to tibia stress fractures.

At this stage it is all theory, and I draw particular attention to the words “maybe” and “try”. Always introduce changes slowly and gradually! Give your body a chance to tell you how it feels about the change before you do any harm to yourself!

So what trainers should I buy?

For those of you still clinging onto the hope that I or indeed anyone is going to be able to give you a structured model for trainer selection, I should probably put you out of your misery. There is no model. But do not despair. See it as liberation as opposed to a hindrance.

Yes, some people are recommended trainers and their injury disappears, but plenty are given the same advice and the injury continues. The journey to injury free running is best started with acceptance & application of the following mantra, as used by running coach James Dunne of Kinetic RevolutionForm Before Footwear.

As far as trainer selection goes, Pete Larson, anatomy professor, writer & runner with self diagnosed shoe obsession sums it up nicely: “I can run in just about anything as long as I’m careful to take things slowly and listen to my body.”

This is what I mean by “liberation.

Part of Pete’s Running Shoe Collection, 2010. (Photo Courtesy of P. Larson)

Part of Pete’s Running Shoe Collection, 2010. (Photo Courtesy of P. Larson)

In my opinion, one of the best things to so far emerge from the barefoot debate is the much larger variety of designs of shoe you can now choose from.

Having seen that heavy cushioning is not necessarily helpful to everybody, you should now hopefully be more confident to test, for example, some lighter trainers. Again, the secret is experimenting to see what feels comfortable for you. Bear in mind that a trainer that suits you for one distance, terrain or speed may not work as well for another.

You could also try trainers with a slightly lower Heel-Toe Drop than you are used to (the difference in height between the heel and the forefoot).

Traditional running shoes have a heel-toe drop of about 12mm. Vibram Fivefingers have pretty much a drop of 0mm. Going straight from 12mm to 0mm is not taking things slowly or listening to your body! There are plenty of 6-10mm transitional trainers on the market which will allow you to experiment more gently.

Though there is as yet no direct evidence for benefits of a lower drop, I personally see much logic in the argument that exposing your feet and legs to varying forces (in a controlled, sensible manner) could potentially make you a stronger runner and reduce injury.

Remember to listen to your body

If you run too far, too often, or too fast in a new pair of trainers, your body will let you know. Many of the running injuries we see in clinic are linked to a runner buying a new pair of trainers and thinking they can pick up their training program from where they left off. It’s more than that. Most runners actually run faster or further the first time they put on their new trainers (we all love new toys!).

  • It is vital to respect the fact that your body will often need time to adjust to a new style of trainer. Put on a minimalistic shoe for the first time and run too far and your calves will soon let you know about it! It’s all about taking it slowly and listening to your body.
  • If you experience a slight discomfort, treat it as a thoughtful message from your body that you need to break the new trainers in a little more gently. Put them away for a while. Go back to your favourite trainers then re-test the new ones with reduced time or intensity.
  • Obviously, if the pain is persistent and affects your running whilst wearing other footwear then get it checked out by a professional, but in my experience most running injuries are the result of either ignoring a warning sign (not listening to the body) or too quick an escalation in frequency, intensity or time.

It may be the shoes, but it’s more likely to be you pushing yourself too much, too soon. Which brings me to my next point…

Use more than one pair of trainers

In order to break in new trainers, you will need to have your all time favorites at hand to wear in between. Your body will warn you if you are doing too much in your new trainers. Listen to it. Put them away for a week, continue with your regular trainers, then go back to the new ones.

Many runners I work with report that exposing their legs & feet to different forces via rotating the trainers they run in leads to (or at least coincides with) less injury. Given that the majority of running injuries are the result of repetitive strain, mixing it up kind of makes sense (and that goes for running surfaces as well). Invest in a few pairs of different style trainers – the chances are you will get your money back by less need for injury treatment!

Have you experienced success by changing to a new style of trainer? Maybe you already rotate different style trainers as part of your running program? We are always keen to hear from you and look forward to reading your comments.

Happy running!

Matt Phillips is a Run Conditioning Coach, Video Gait Analyst & Sports Massage Therapist with over 20 years experience working within the Health & Fitness Industry. Follow Matt on TwitterAnd for more great training, nutrition, maintenance info, check out the RunnersConnect blog.

Where Are You Most Likely to Get a Stress Fracture?

Research to Help You Catch Potential Stress Fractures Early

Guest blog by John Davis (RunnersConnect)

stress-fracture-1-1stress fracture is one of the most feared running injuries. With a virtually guaranteed six or eight-week layoff from running, the prospect of sustaining one is unsettling even to veteran runners who have dealt with other injuries. Additionally, the fact that it’s a boneinjury—something we usually associate with hard falls or other traumatic incidents—gives a stress fracture an additional tone of seriousness.

Intuitively, the bone doesn’t seem like it should be injured from something as basic and “normal” as running. But, as many runners discover every year, stress fractures are a reality. Progressive stress on the bones, either from impact with the ground or the “active force” that occurs when you push off the ground, can surpass your bones’ structural integrity, leading to a stress fracture.

As such, being aware of where stress fractures occur and how common the various locations are can help you catch one early, potentially sparing yourself weeks of time off from running, or even prevent one entirely.

The science behind where runners get stress fractures

While, in theory, any bone in the lower body can get a stress fracture, in practice they are much more common in some locations than in others. This likely has to do with some universal biomechanical principles that apply to running, though these are poorly understood as of right now. One simple example might be the tibia and fibula. These two bones make up your lower leg, but while the tibia is much thicker than the fibula, it is much more likely to sustain a stress fracture. This is probably because it bears most of the weight while running, the fibula being relegated to a “support” role. To get a better picture of where stress fractures occur, we’ll turn to the scientific literature.

A cursory review of the literature reveals that stress fractures account for around 20% of all injuries in runners.

While this is substantial, it’s nevertheless difficult to conduct large studies on the location of stress fractures among all types of runners. For this reason, studies tend to focus on groups of athletes that are at a higher risk for stress fractures. This is the case with both studies we’ll look at today.

Fractures In Focus

The first is a 2003 paper by Elizabeth Arendt and colleagues at the University of Minnesota. In this study, ten years’ worth of college athletes were tracked and the patterns of stress fractures were analyzed, both by sport and by gender.

  • Like many sports injuries, stress fractures were more common in women, with about three female athletes getting a stress fracture for every two male athletes.
  • Distance runners, who accounted for the largest proportion of the athletes with a stress fracture, tended to suffer from stress fractures to the tibia, femur, fibula, metatarsals, and navicular, with the tibia being about twice as common as the others. No stress fractures to the pelvis or spine were reported.

Unfortunately (for our purposes at least), Arendt et al.’s study only counted 23 stress fractures in runners. While this is fantastic for the athletes in those ten years, our ability to predict where stress fractures occur is somewhat limited by this relatively small number.

An earlier study by Gray Barrow and Subrata Saha at Louisiana State University addresses this issue.

Using surveys mailed to female varsity distance runners at colleges and universities across the United States, Barrow and Saha collected information on the incidence and location of stress fractures in the sampled athletes. Since the population studied (female distance runners) were at a significantly higher risk for stress fractures, and given that women whohad suffered a stress fracture were probably more inclined to respond to the survey, it is no surprise that 89 of the 241 women who responded had suffered at least one stress fracture from running.

In total, 140 stress fractures had occurred in the 89 subjects.

The tibia accounted for 64% of these, followed by the metatarsals at 21%, the fibula at 9%, and the pelvis, calcaneous (heel bone), & tarsal (midfoot, including navicular) bones at 3%, 1%, and 1%, respectively.

Additionally, the number of respondents allowed Barrow and Saha to break down the specific locations of stress fractures on the tibia, fibula, and metatarsal bones.

  • On the tibia, half of the stress fractures occurred in the distal third of the tibia, meaning somewhere along the first third of the bone’s length, starting from the ankle. The other half were divided about evenly between the middle third and top third of the tibia.
  • Among the metatarsals, the long bones that make up the midsection of your foot, the second metatarsal (the one corresponding to your “index toe,” or the one next to your big toe) accounted for fully half of all metatarsal stress fractures. Another quarter occurred in the third metatarsal, with the fourth and first metatarsals accounting for 14 and 10%. No runners in this study suffered a fifth metatarsal stress fracture.

What you can take from this research

Any persistent running injury deserves to be seen by a doctor. However, if runners were to run (no pun intended) to the doctor every time they felt a little niggle, we’d be broke and doctors and health insurance companies would be lining their pockets. As such, we can use this research to better identify what pain might be a serious stress fracture and avoid costly breaks in training and trips to the doctor.

  • As we’ve learned from the research, runners—especially female runners—should be particularly attuned to their tibia and metatarsal bones, as these are the most common bones to suffer a stress fracture.
  • In the tibia, stress fractures can occur anywhere, but are most common in the lowest third of the bone. In the metatarsals, the second and third metatarsals account for three-quarters of stress fractures.
  • While stress fractures to the femur, pelvis, and navicular are particularly worrisome due to their reputation for poor healing, they are fortunately exceedingly rare.

When it comes to preventing stress fractures, there’s no perfect recipe, but as we’ve seen in other articles, strategies like increasing your stride frequency, being smart about your training, and paying attention to your diet and overall health are evidence-based methods to reduce your risk.

Get more great injury prevention advice from John Davis (plus other great training & maintenance tips from Jeff Gaudette & Co) on the RunnersConnect blog.

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