Tag Archives: plantar

Running Footwear: A critical look at what we know about footwear and how to select the best fit for your athlete

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The media likes to spin things to make headlines. I’m not too big on spinning, I’d rather just help educate. If you’d like to clear the air and see what we know, what we don’t know, and what’s been spun, you can check out this webinar I’m doing for USA Track and Field next week on Mar 26th. Coaches will get CEU’s from their couch.

The make of running shoes have historically gone from one side (thin and flexible) to the other (stiff and bulky) and are now moving toward the middle of the road. Which is best? And how do you match running shoes to an individual runner? In this webinar presentation, Jay Dicharry will comb through relevant research and clinical experience to help you approach your running retailer with the knowledge of selecting the right tool for the job. Learn how to ensure that you are running in your shoes rather than your shoes running you! By the end of this webinar you’ll be able to understand:

  •                 the evolution of footwear
  •                 how footwear has been classically prescribed
  •                 proof that this fit model is ineffective
  •                 how shoes impact your running form
  •                 how barefoot running impacts your form
  •                 how shoe wear impacts your form
  •                 how to select shoes for you
  •                 what minimal shoes are, and if you are ready to make the transition

Proprio-what? a deeper look at balance and stability

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Yesterday’s post got lots of comments; I’d like to post a bit more here to help folks understand this concept a bit deeper. Why does this idea about balance matter at all to runners? Midstance is basically single leg standing balance. However there is a difference between “reactive balance” and “proprioceptive control.”

Let’s define a few terms here:

Strength – relates to the cross-sectional area of a given tissue. This is related to the muscle’s ability to generate force. Bigger muscle, bigger force. Simple.

Proprioception: there are 3 primary things we use for balance.

  1. Vestibular  (inner ear) – If you are standing still, inner fluid is still. If you turn your head suddenly, the inner ear fluid swirls and this information goes to your brain to help determine acceleration and change in position.
  2. Somatosensory – You “feel” the ground. You have sensory receptors in your skin which allow you to feel something – light and deep pressure, vibration, heat, cold, etc. This sensation goes a long way to improve your tactile feedback to help you remain stable.
  3. Vision – We use our eyes to orient our head and trunk and let us know which way is “up”.

Note- you do have other reflexes that play a role here, but these are the primary ones that have the greatest effect.

If these 3 systems “agree” then you are using your body as best you can to achieve control in stance. So let’s look at examples of how these can change. If you are on a merry go round, your eyes see you are spinning, your somatosensory feels the body turning, and your vestibular system says you are spinning. Everything is fine. If you stop, your eyes and somatosensory system say you have stopped, but your inner ear fluid is still swirling – signals don’t agree….. and you become dizzy.

So why is it harder to close your eyes in single leg balance? Most folks are visual dominant. They rely highly on their eyes to find their position in space. The problem with this is that it’s “slow.” You need to see information, process it in the visual part of your brain, then send a signal to the part of your brain that control motion (motor cortex) to make a correction. Somatosensory information is very very fast. There is a direct relay between the sensory and motor reflexes both inside and outside the brain – resulting in fast rapid “micro-corrections” of position. Let’s use an example.

If you look at skiers, surfers, skateboarders, white water paddlers – they all have something in common – they need to make positional corrections VERY quickly – faster than they can see visually and adjust. They get good feedback about the position of their body from their hard ski edge (transferred up through a very stiff plastic boot), or the rail of the surf board (transferred through their bare feet). Each and every time they practice their sport they are refining their position sense by “feeling” where the body is. They consistently train and improve their somatosensory system.

Research shows that the somatosensory system is highly trainable. Its best done frequently in small doses. Instead of trying to balance on one leg for 10 min each night, its better to do it 20x’s a day for 30 seconds. Yes, you CAN improve your balance….by practicing.  Not your “I’m-rocking-back-and-forth-like-a-weeble-wobble” re-active balance, but your “proactive balance.” Proactive balance means “I know what to do to keep my body stable – I can micro-correct to improve my stability.” Think about spreading your toes out wide to maximize the width of your foot. Try to push your big toe down – not curling, just down as you keep it straight. This will improve your muscles firing inside your foot. I’ll make a deal with you – if you work on your single leg balance every day, you’ll find not only will you be able to stand with eyes closed, but also be able to begin to rotate left and right with your eyes closed. The goal is to reduce your dominance on vision and improve your use and perception of “feel.” It works!

OK – so let’s now look at this with respect to running. I’m going somewhere with this I promise – I’m building a case for you. There is a ton of research that supports the idea that firm surfaces offer better “feel” to the individual and thus better balance control. Soft surfaces mute the feedback to the person and result in poor stability in stance. The goal is to maximize your level of active stability control that your body can produce.

If I am in the clinic working with a patient, I always work them in barefoot, and will use all kinds of rocker/wobble/rolling boards to do this. All of these are FIRM and HARD surfaces. Even though the foot is moving, the contact between the ground and the foot is solid. The person gets good feel for what is happening. I am not a proponent of foam pads to work on balance. Why? Foam pads let you cheat and roll off to the outside of the foot. They don’t mandate that you activate the big toe. They don’t train “pro-active control.”

Let’s take this idea and now apply is to footwear and the entire rationale for you reading this post. What is traditional footwear? – It’s got an elevated heel, a wider lever arm than your foot, and a big marshmellow stuck underneath. This marshmallow allows your weight to shift to the outside of the foot. The heel-higher-than-the-forefoot provides a “rocker” in front of the shoe that you can simply roll off of. It lets you “cheat” by conforming to your foot. A lot of runners have gotten used to this.  Their feet have become weaker as the shoe does more of the work.

When we look at minimal footwear or barefoot running, this foam pad is gone completely or reduced significantly.  Suddenly, you can’t cheat. You have to actively use the muscles inside the foot to stabilize. The absence or reduced cushioning in the shoe allows you to get better “feel”  – why do so many proponents of barefoot and minimalist running claim that they feel “free” or like they’ve “been released”…….? It’s simple – your foot gets more information from the surface you are on when you don’t have a big piece of compressible foam in the between. More information  = better muscle activation.

I see a hand up in the audience.

Q: So I’ve been running for years and I still can’t stabilize with my eyes closed. What gives?

A: closing eyes might be slightly overkill, but you know what? – Almost every standardized assessment for balance testing has an eyes-closed component to assess just what we mentioned above (the 3 things that impact proprioception). So if you have good balance with eyes closed, I know that you are good in this regard and not going to ask you to add this into your training program. It allows the examiner to differentiate how well you use different skills that affect balance. If the eyes closed part is the issue, and this is connected to faulty foot and ankle mechanics during running, it give me more information as to what your limiters are as a runner.

Q:  So I’ve been running for years, and I still can’t stand on one leg – even with my eyes open. What gives?

A:  There is no research to show that your poor balance will result in injury, but there is research to show that those with a number of lower extremity injuries do have poor balance. Further, I’ll be happy to say that those with poor single leg balance almost always have some very interesting finding in our lab – they usually have altered forces around the ankles which results in abnormal stresses to the lower leg and foot. Improving your single leg balance is a way work on prevention. I’d much rather you not get hurt and keep enjoying your runs, than not. Maybe you are one of the lucky ones who has run for years without injury – awesome! However, research shows that 82% of you runners will be hurt at some point. Both personally and professionally, I’d rather see you in the 18% of those who are not.

Do shoes have feelings ?

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Let’s say you are out for a night on the town. Your significant other turns to you and says how do you like my outfit? Unless you answer this question perfectly (still not sure how to answer this even after many years of marriage!) you may notice that your significant other withdraws for a while to cool off. Could be a few minutes, could be for the night, but this time away allows things to mellow and return to a state of bliss yet again. What does this have to do with shoes?

It’s common practice for a lot of runners to have multiple pairs of shoes at one time. This though process behind this has been that running in a shoe breaks down the cushioning properties of the shoe, and it takes time for it to rebound before your next run.

Well, Let’s look at some objective information on this subject. This is not going to turn into a discussion of minimal shoes vs. traditional construction. We are simply going to look at what happens to the properties of the midsole itself. The midsole is the squishy part of the shoe that lies between your foot and the tread. Its commonly made of a chemical compound called ethyl-vinyl acetate (EVA). Shoe manufacturers manipulate properties of the midsole to get their shoe to perform a certain way. Obviously a minimal shoe has less of this midsole material in it then a traditionally constructed shoe, but they both have some type of cushioning material between the foot and the shoe tread.

As you run, you are applying mechanical forces to the shoe itself. These forces physically break down the midsole. In fact, lets look at this at the microscopic level. The following picture is from a study (1) that looked at the state of the midsole at various points in the shoe’s lifespan. In fig A, you are looking at an electron micrograph cross section of a brand new shoe. It’s easy to see the outline of the well defined air pockets in the midsole. This intact formation allows the midsole to perform as it was designed. Fig B shows a cross section of the midsole after 500 kilometers (310 mi). This type of magnification allows you to see that the edges of the former well defined air pockets are now frayed and weakened. Finally, Fig C shows the midsole after 750 Kilometers (466 mi). It is now possible to see that the majority of the air pores are frayed, and in fact some of them have actually deformed enough to create holes. Thus, the structural properties of this midsole material are now very different from what they originally were when new. While your body can repair tissues that have been affected from mechanical stresses in running, your shoes cannot. Resting your shoes by the front door between runs won’t reverse these changes.

While it’s probably a good thing to be nice to your shoes (running in wet environments with no chance to dry out may accelerate breakdown of the midsole), they don’t have feelings. You can pound on them day in and day out  – even 2 runs in the same day. The breakdown of the material in your shoe is cumulative. So what happens to our gait as shoes breakdown?

A 2009 article (2) revealed that running in worn shoes caused the runner to increase their stance time (time spent on the leg) and alter their lower leg range of motion in order to keep forces on the body somewhat constant. What does this mean? As your shoes break down, the body will slightly alter its gait style adapt to the gradual changes that occur in the shoe itself.  When do these gait alterations reach critical mass (causing injury if you don’t buy new shoes)? Shoe breakdown is variable depending on the runner’s mass, running surfaces, and gait style. I know runners who note that they become injured if they put more than 250 miles on their shoes, and I know runners that put well over 1200 miles on a single pair. The old school rule of thumb states 400-500 miles, and is likely a good starting point based on the research stated above.

Happy Running!

  1. Verdejo, R. , Mills NJ. Heel-shoe interactions and the durability of EVA foam running-shoe midsoles. J Biomech. 2004. Sept; 37(9):1379-86.
  2. Kong, PW., Candelaria, NG., Smith, DR. Running in new and worn shoes: a comparison of three types of cushioning footwear. Br J Sports Med 2009 43: 745-749

Loading Rate: Part 2: Forefoot, midfoot, rearfoot……..Who cares?

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Yesterday we briefly discussed the idea of loading rate, and why it matters to you as a runner. Today we’ll talk of the 3 primary ways runners can change loading rate, and likely dispel some myths while doing so. If I ruffle some feathers while doing this, don’t get frustrated. Its good to stretch you brain.  Let’s look at what we do know about loading rate, and what is a bit fuzzy.

Methods to decrease loading rate involve a combination of:

  1. A foot contact style closer to the body’s center of mass
  2. Minimizing excessive lumbar extension (which shifts the body’s center of mass posterior in relation to foot contact)
  3. Changing limb stiffness through feedback training.

****Warning – some of this gets a bit tedious, but there has been a lot of request for this information lately, so lets dive in shall we?

Let’s get right to the hot topic. Should you land on you forefoot, midfoot, or rearfoot?

Right below, is a graph of a runner landing with a midfoot gait. You’ll notice a very distinct impact peak (first bump) and a larger active peak (second bump). You’ll also notice that the slope of the first bump (from the x-axis to the top of the first bump) is quite steep.

What kind of foot contact pattern made this graph? Nope – not a heel striker – but a midfoot striker. In fact this woman is about as midfoot as possible – her foot came down completely flat down at contact. I know ….this runs counter to a lot you’ve been told right? Hold on – let’s keep going.

Now look at runner #2’s graph. Notice the single mountain (or peak). Notice that the slope of the line from contact to peak is quite less steep than that of Runner #1. A LOWER loading rate! Guess what kind of contact style this runner utilized? A heel-strike. Yes. You read that right. A heel striker had a lower loading rate than a midfoot striker …..in this situation.

What gives? The media tries to make things simple. They say that “mid-foot” or “forefoot” is better than rearfoot. I love reading running forums where people with way too much time on their hands armchair quarterback running styles. They look at a picture or video of a contact pattern of some guy running across the screen and say “wow – nice midfoot strike –that runner is efficient.” They don’t know who the runner is, or what his time was for the race. They just saw a foot strike and proclaimed him efficient. Then they’ll scroll down and see some picture or video of some guy heel striking and proclaim that he/she is an “in-efficient” runner based on the heel strike. This “in-efficient” runner might be an in-efficient runner. Or it might be Meb Keflezighi (a runner who is just a bit faster and more efficient and than most of your reading this post).  You see, these arm chair-quarterbacks aren’t very good at identifying efficient gait. Fancy force plates are. I do this for a living and still need data from my lab to give me the answer because no one can actually see forces. So what have we learned from these fancy force plates?  Its NOT rear-foot or midfoot or forefoot that matters – its where the foot contacts in relation to the body’s center of mass.

As I stated above, I picked some outliers just to make a point. It is true that for MOST runners, adopting a midfoot or forefoot gait style will lead to decreased loading rates. However, its not because the foot lands differently, its because a rear-foot style typically allows you to land with the foot farther in front of the body’s center of mass (over-striding). Switching to a contact style that moves the foot closer to the body’s center of mass usually means that we land closer to the font of the foot. But not always. Let’s look at the elite runners to dig a bit deeper.

To run really fast, it’s very simple. You either increase your stride rate or your stride length. Simple right?

  • Stride rate- this is also referred to as cadence. Cadence ranges in cycling are pretty variable. Cyclists use anywhere from 45 – 140 rpm in competition, depending on the event and terrain. When we look at running, you’ll notice that cadence for middle distance through marathon distance typically ranges from 88-96 rpm. This is a much narrower effective window than cycling. We’ll look more in depth at cadence in a later post, but for right now, its safe to say at the elite level, there isn’t a huge difference in cadence values.
  • Stride length –if cadence values are held fairly consistent, the only other way to run faster is to adopt a longer stride length. The stride length of someone running 4:30 miles is significantly longer than running 7:45 miles. What we see is that a number of the elites land on the rearfoot, but their center of mass is still very high up at the time of contact. When running, you are a projectile in the air with your center of mass following a parabolic curve. So even though the elites often “contact” on their rearfoot, they don’t really have much pressure (force) on it until their center of mass lowers to the ground.  This effect produces a low loading rate with a heel contact, and is exactly what occurred in runner #2 above.

So let’s summarize what we’ve said about contact foot contact style. For most runners, landing closer to the body’s center of mass is an effective tool to lower loading rates. Barefoot running, minimalist running, and increasing cadence (faster cadence means you don’t have time for your foot to reach out far in front of the body) are all effective tools to accomplish the end goal of decreasing loading rate.  This being said, contact style is NOT the only way to decrease loading rate. Its possible to have lower loading rates with multiple foot contact styles, and other factors as well.

***Note: Unless the person is accelerating, it is not possible to have the foot contact directly under the center of mass. At steady state, the foot does (and should) contact in front of the center of mass.

The effect of posture

We said that, in general, a foot contact closer to the center of mass would decrease loading rate. On the flipside, posture can be utilized to alter the center of mass in relation to the foot. Most of us stand, walk, run, etc with poor posture. Take a look at the runner below. The runner is in exactly the same phase of gait, except for a more arched low back on the right than on the left. The posture on the right is typical to most runners. We hang out in the “back seat” with lots of arch in the low back. This change in lumbar position moves our center of mass backwards thus causing our foot to land further in front of the center of mass.  Therefore, keeping a neutral lumbar spine (not arched) is essential to keep our center of mass over our foot when running – and has the effect of minimizing loading rate.

Lastly – gait cueing and limb stiffness. Here’s where things come together, but also show need for additional research. In our lab, when we get someone with high loading rates, we show them their ground reaction force plots in real-time as they run, and ask them to change it. Normally, we don’t tell them how, we ask them to “play” with their graph shape as they run. Most runners figure out how to minimize their loading rates by getting visual cues, or feedback. This is the best way since the runner is aware of the conscious modifications they are doing to alter their loading rates and can see instant feedback to observe success – thus learning! If they don’t “get it”, we guide them through the technique modification so they can see the effects of their form changes as they run. Again – the goal is to get the runner to retain this sensation so they can alter their gait to make long-term changes to decrease tissue stress.  On the simpler side, research has been done that simply told runners to “run soft”. These individuals were found to decrease their loading rates. Gait cueing works. How does it work? People modify their contact style, posture, and their limb stiffness to achieve a desired result. Limb stiffness relates to how compliant the runner maintains the knee to modulate the rise and fall of the center of mass. There is more work to be done here to dig deeper, but this should hopefully answer the bulk of questions for now.

Summary:

What does this mean for you as a runner?

There is mounting evidence that minimizing loading rate has vast implications for a number of injury prevention strategies. There is also mounting work to show links to performance, though this is inconclusive at this time. There is additional work to be done to show how the gait style changes observed with decreased loading rate correspond to improved performance. Another topic for another day……

If you want to try to decrease your loading rate, you need to get your foot to land closer to the body. Barefoot running is a good drill for this since it “forces” you to avoid over-striding.  There is evidence that a properly constructed minimal shoe should also lead to minimal loading rates (although no one can say all minimal shoes since the definition of this market sector is so vague). Keep your torso centered over your lower body and avoid the temptation to run in the “back seat”, especially as you fatigue.

Run Tall! Run Soft!

Yup…. Less (loading rate) = More.

Plantar Fasciitis

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Plantar fasciitis is one of the most common injuries in runners, recreational and competitive alike. Although it can be frustrating to experience, there is good news for plantar fasciitis sufferers: it gets better! This frustration is perhaps best illustrated by the bumper sticker available at the Ragged Mountain Running Shop that reads, “I survived plantar fasciitis!” Mark and Cynthia don’t dispense stickers proclaiming the survival of stress fractures or runner’s knee. Perhaps the mystery regarding the healing of these injuries are more widely understood. Implementing a comprehensive approach to plantar fasciitis will help ensure a more speedy recovery and return to full training.

The plantar fascia is a broad band of tissue that starts at the heel, then widens as it extends through the foot to attach near the toes. The fascia supports the arch and foot musculature. The fascia is most commonly injured near its insertion at the heel. There are good reasons for this: the fascia is stressed with impact loading at every heel strike, then is stretched as we go through the gait cycle. The area near the heel also has less blood supply than other regions, thus limiting its healing capacity. Pain occurs on the bottom of the foot near the heel and is particularly noticeable first thing in the morning as well as during and after running. As symptoms worsen, the runner may also have pain after sitting for a long period of time or sometimes with every step! The term fasciitis is perhaps a bit of a misnomer as it implies that inflammation is the cause. Inflammation is just part of the package. In addition to inflammation, scar tissue and even tearing can occur. This explains why anti-inflammatories alone rarely prove curative.

Treatment includes measures to control pain and inflammation, minimize overload forces, and to promote tissue healing. Proper shoe wear is essential. Anti-inflammatories are useful (as long as there is no reason not to take them ie allergies to anti-inflammatories or aspirin, pregnancy, or if you have a history of stomach ulcers, or kidney or liver disease). In chronic or especially painful cases, I may prescribe a short course of oral steroids first. Stretching of the calf muscles and plantar fascia is performed. Remember to perform the calf stretch with the knee bent as well as straight as these 2 positions emphasize different muscles. The fascia is stretched by extending the toes against a wall or the floor. Strengthening the foot and ankle muscles is important. Useful exercises include towel scrunches, picking up marbles, and “short foot” exercises, where the runner stands on one foot while maintaining the arch of the foot. Several devices are marketed to assist with plantar fasciitis. I have found good success recommending the counterforce arch brace designed by my sportsmedicine mentor, Robert Nirschl, MD, MS and available through running shops or direct from Medical Sports, Inc. Other useful devices include gel heel cushions and over the counter orthotics. If symptoms persist beyond 6 weeks of this level of treatment, formal physical therapy can be useful to apply modalities such as iontophoresis (delivering anti-inflammatory medication with an electric stimulator) or ultrasound, manual therapy to ensure proper joint motion, and expanding one’s exercise regimen. A night splint designed to apply a light stretch while sleeping can be useful. In select instances, custom orthotics may be indicated to control specific biomechanical contributors. In longterm or particularly painful cases, steroid injections can be applied to help facilitate the rehab process. Since steroid serves only to control inflammation, injections should not be viewed as treatment in and of themselves. Additionally, since steroids can potentially weaken the local tissues, I recommend refraining from running for 10-14 days after this type of injection.

In rare instances, surgery may be indicated, but is recommended only after the runner has failed to respond to the conservative treatment for several months. Alternative therapies also exist: shock wave therapy, magnets, and accupuncture. Although these may prove to be more useful, we simply have limited experience and research regarding these treatments. They can also be costly, and therefore are not as widely used.

There are other, less common causes of heel pain in runners including a bruised heel pad, stress fracture and nerve entrapments. Imaging studies such as xrays, bone scan, or MRI and nerve testing may be recommended if the runner is not responding to treatment or if initial presentation suggests a different cause.

Most runners may continue to train while plantar fasciitis is being treated, as long as the pain is considered mild and is not forcing a change in the gait. If pain is more than mild, back things down a level. Don’t run, however, if pain forces you to limp or change your gait. If you have to alter your training schedule, substitute cross training to maintain fitness. I recommend water running, the elliptical, or biking. Train at similar intensities and durations that you would for your land training.

Be patient, yet diligent with the rehabilitation program. And once resolved, you can proudly display that sticker!