The Power of ENGO

December 5, 2017 by · 1 Comment
Filed under: blister care, Foot Care, Foot Care Products, Footcare, Footwear 

Tamarack Habilitation Technologies, a company dedicated to the prevention and relief of skin breakdown for individuals with prosthetic limbs and orthopedic braces, created ENGO Blister Prevention Patches in 2004. The patches are designed to prevent blisters and reduce pain from existing blisters. These patches are one of the best products to help athletes that have been released in many years. I think two or three of these thin ENGO Patches patches should be in everyone’s foot care kit.

ENGO Heel Patches

ENGO Heel Patches

ENGO low-friction patches are applied to your shoe, insole, or orthotic—not your skin. The patches are made with three layers: a low friction outer surface made of polytetrafluoroethylene (PTFE), a fabric backing, and an adhesive. Patches range from small and large ovals to a large rectangle to a shaped strip for heels—and each can be cut to size. These thin patches can greatly reduce friction in targeted locations within your footwear by giving a slick, slippery surface to the area of your footwear or insole where friction is a problem. Socks slide over the patch, reducing the usual drag, which allows the foot’s skin and the sock to glide with the underneath bone through the foot strike, reducing shear distortions in that area.

ENGO offers multiple advantages over other blister prevention and treatment products:

  • Reduction in friction levels
  • Targeted protection at the specific problem area to reduce friction
  • Durable and can last for months
  • Cost-effective based on their small size and durability
  • Well tolerated because it is placed on and in footwear
  • Takes up virtually no space so it doesn’t change the fit of the shoe
ENGO side of the foot patch

ENGO side of the foot patch

ENGO patches can work in footwear to reduce shear, prevent blisters, and provide relief almost anywhere on the foot: the bottom and sides of the heel, ball of the foot, side of the foot, and arch areas. Patches should be applied to dry and clean footwear, which makes them perfect for proactive prevention. Sometimes when shoes are wet, patches are applied to dry socks. The patches have many uses, including on bike seats, paddles, tool handles, and more.

ENGO rectangle patches in a package

ENGO rectangle patches in a package

Types of ENGO Patches

ENGO patches come in small and large ovals, back of the heel patches, and rectangles. A good rule of thumb is to select a patch that is slightly larger than troubled area or blister. Select the patch that is right for you, based on the area where you have a blister:

  • Heel: ENGO Back of Heel Patches
  • Arch: ENGO Large Oval Patches
  • Ball of foot: ENGO Oval or rectangle
  • Side of foot: ENGO Large Oval Patches
  • Toes: ENGO Small Ovals
  • Skates, Helmets, Boots: ENGO Rectangle Blister Patches
  • Multiple Blisters: ENGO Blister Prevention Patch Variety Pack

Using ENGO Patches

  • Remove half of the patch from the backing, using the backing to create a tab. Use tab for handling patch.
  • Apply adhesive side of ENGO patch to desired location of clean, dry footwear.
    Tip: ENGO may last longer when anchored to a surface. For example, wrapping patches around the edge/sides of the insole.
  • Peel remaining backing away from patch.
  • If blisters form at interface of footwear & insole, use two patches. One patch is placed on the footwear. The other patch is placed on the insole. A smooth interface is created.
  • Press firmly around entire patch surface to secure.
  • To protect remaining patched and preserve their quality, store your unused patches in the re-closable, heavy duty ENGO bag that they came in.

Tamarack is always developing new products, for instance, a thin lowfriction tape that could be useful for athletes and special socks with a low friction forefoot. The best way to connect with Tamarack is through the ENGO website, goengo.com.

Note: ENGO patches need to be applied to dry shoes.

Finding the Right Combination

November 22, 2017 by · Leave a Comment
Filed under: blister care, Foot Care, Footcare, General, Health, Sports 

This is Part V in a series about blister formation and prevention. Below are links to the first four parts of the series.

Finding the Right Combination

Each athlete needs to find a blister prevention strategy that works for him or her. One may use a lubricant, another may use Zeasorb powder, and yet another may pretape his or her feet. Each may use one of many types and styles of socks. There are many combinations. Remember, the goal of all these components is to reduce shear stress by bone movement, pressure, friction, and moisture; increasing skin resiliency; and absorbing shear. A look at the image will show how the 5 Blister Formation Factors (the 2nd outermost circle) and the 13 Blister Prevention Components (the two inner circles) are related.

Five Circles 1

High-level views of the factors in blister formation and components in blister prevention
The legend for the inner circle: G=Gaiters T=Taping N=Nutrition and Hydration C=Shoe and Sock Changes I=Insoles and Orthotics L=Lacing A=Antiperspirants S=Skin Tougheners and Adherents

Five Circles 2

 

Try any of the suggestions and find those that work for you. Some will and some won’t. That’s OK, because it’s a process. You are gathering information that will help you now, and file away other information that may help you later.

At the 2017 Western States Endurance Run I treated many runners who had ignored my advice about Running a Wet 100 Mile Trail Run posted on my blog two weeks before the race.I gave advice based on my years of experience in working on feet in multi-day races around the world. Things like clean socks, powder and lubes made for wet conditions in drop bags. And carry the same in hydration packs. I gave proactive advice on caring for one’s feet. It seemed the majority of the runners I treated had not read my blog post. because more runners than usual had badly macerated feet. The did not take advantage of a few of the components mentioned above.

Here are two more examples of runners using blister prevention components in combination.

Ultrarunner Dave Scott claimed his feet are often “as soft as a baby’s bottom” after the 100-mile Western States Endurance Run. Dave found that he rarely had foot problems. He trimmed his toenails, used a small amount of petroleum jelly, and regularly changed his shoes and socks. That is what worked for him.

Ultrarunner Tim Twietmeyer has won the grueling 100-mile Western States Endurance Run five times while accumulating 25 silver belt buckles for finishes less than 24 hours. Over the years, in addition to running ultras, he has enjoyed fast packing in the California High Sierra. He has found the differences interesting.

A week before running a 100-mile trail ultra, Tim trimmed his toenails as short as possible. The morning of the run he coated his feet with lanolin to reduce friction, provide warmth if running in snow or through water, and make his skin more resilient to getting wrinkled. Then he pulled on a pair of Thorlos Ultrathin socks. His strategy is “that the more sock you wear, the more moisture close to the foot. The more moisture, the more blisters and skin problems.” He usually wore the same pair of shoes and socks the entire way. Tim acknowledges, “My feet don’t usually have problems, and when they do, I’m close enough to the end to gut it out.”

Tim found that fast packing affected his feet differently. When he hiked the John Muir Trail in 1992 (doing 210 miles in five days and 10 hours), his feet were trashed more than ever before. His group of five experienced ultrarunners averaged 14 hours per day on the rough trail. Tim remembers, “We covered the ground so fast that my feet swelled and I almost couldn’t get my shoes on the last day.” He used the same strategy of using lanolin and thin socks. Instead of running shoes, he chose lightweight hiking boots. Foot repair became the group’s daily ritual as the 40-mile days took their toll. They realized that “an important strategy for keeping our feet from getting any worse was to get that first piece of duct tape on in just the right spot and make it stick. If we did that, our feet held up pretty well.” By the end of the fifth day, the last piece of duct tape had been used on their feet. Tim’s

cardinal rule for fast packing is to “keep your feet dry.” That can be hard to do when fighting afternoon thunderstorms, but when your feet are wet too long, it’s only a matter of time before they blister. Whether running ultras or fast packing, Tim knows the importance of keeping his feet healthy, and he has experimented to find what works well for him.

Both Dave and Tim used a combination of components: skin care, socks, lubricants, taping, toenail care, and changes of shoes and socks in an effort to prevent blisters. Determine what foot problems you normally experience, study this book, and then begin the task of finding what works best for your feet.

We need to understand the importance of other elements that contribute to prevention. Proper strength training and conditioning will help make the foot and ankle stronger and more resistant to sprains and strains. Everything you put on or around your foot becomes related to how well your foot functions. Keep in mind that whatever you do, the aim should be to reduce shear, moisture,

The Components of Prevention

November 12, 2017 by · Leave a Comment
Filed under: blister care, Foot Care, Foot Care Products, General, Health, Sports 

This is Part IV in a series of posts about blisters, their formation, causes, and prevention. In this post we look at the 13 components of blister prevention – five major and 8 minor components. They all play a role and are important to understand.

Blister prevention takes place through a combination of 13 components. Five are the most major components: fit, socks, ENGO patches, lubricants, and powders. Eight others are minor but still important components: skin toughening agents, taping, insoles and orthotics, skin care and hydration, antiperspirants for the feet, gaiters, lacing, and changes of socks and shoes.

Within our shoes many things are happening, and everything is related in some way. Where something touches another, we have what we’ll call an interface. The basic interfaces are between the skin and sock, the sock and the insole, and the sock and the inside of the shoe. When you put tape on the skin, it adds two more, between the skin and tape, and the tape and the sock. Adding an ENGO patch adds two more. Since the tape and the ENGO patch are stuck to the skin and shoe respectively, the only interfaces we are concerned with are the tape and the sock, and the ENGO patch and the sock. The interface with the lowest COF determines or limits the magnitude of friction. If the tape loosens on the skin, another damaging interface is added.

The Five Major Components

We’ll start with the top circle comprised of fit, socks, ENGO patches, lubricants, and powders—the first line of defense against blisters. It’s important to remember that these five components and the eight from the next circle all work in some way to reduce shear distortion. They may increase skin resilience; reduce bone movement, pressure, friction, and moisture; absorb shear; or reduce the number of repetitions. Remember that the more you use shear-reducing or shear-absorbing materials in your shoes, the more you are taking that stressor off the skin.

  1. FIT comes first. You need to start with properly fitting shoes with a quality insole. No matter how well you tape, how good your socks are, or how good any other component is, if the shoes fit incorrectly, you will have problems. If your footwear is too loose, your feet will slide around, creating shear. If your footwear is too tight in certain areas, your feet will experience excessive pressure. Wearing too-loose or too-tight footwear will change the biomechanics of your foot strike, which in turn will affect your gait and throw off your whole stride and balance.
  2. SOCKS come in either single- or double-layer construction. Some singlelayer socks, particularly those without wicking properties, allow friction to develop between the feet and the socks, which in turn can create blisters. Double-layer socks allow the sock layers to move against each other, which reduces friction between the feet and the socks. Socks can also wick moisture away from the skin. Injinji toe socks give each toe its own sock.
  3. ENGO BLISTER PREVENTION PATCHES are effective at reducing shear distortion by reducing friction at the skin and sock–shoe interface. The patches are an alternative to taping.
  4. LUBRICANTS create a shield to reduce friction and protect skin that is in contact with socks during motion. This lubricant shield also reduces chafing.
  5. POWDERS reduce friction by reducing moisture on the skin, which in turn reduces friction between the feet and the socks.

 

Prevention Components

The 13 components of defense against blisters

LEGEND

Outer Circle: Fit, Socks, ENGO patches, Lubricants, and Powders.

Inner circle: G=Gaiters T=Taping N=Nutrition and Hydration C=Shoe and Sock Changes I=Insoles and Orthotics L=Lacing A=Antiperspirants S=Skin Tougheners and Adherents

The Eight Minor Components

Now, imagine another circle made up of eight components that play a strong supporting role in prevention—the second level of defense against blisters. This innermost circle is made up of skin toughening agents, taping, insoles and orthotics, skin care and proper hydration, antiperspirants for the feet, gaiters, lacing, and frequent sock and shoe changes. Each can contribute to the prevention of blisters and other problems. You could argue that these outer components should be identified as major components, and to some extent you may be right—some components may be more important for your feet than for mine. The trick is to determine what we each need to keep our feet healthy under the stresses of our particular sport. Let’s look at each component.

  1. SKIN TOUGHENING AGENTS form a coating to protect and toughen the skin. These products also help tape and blister patches adhere better to the skin and lead to a reduction in perspiration.
  2. TAPING provides a barrier between the skin and socks so friction is reduced. Proper taping adds an extra layer of skin (the tape) to the foot to prevent hot spots and blisters. Taping can also be a treatment if hot spots and blisters develop. ENGO patches can be an alternative to taping or compliment taping. Toe caps are silicone gel devices that go over the toes and absorb shear.
  3. INSOLES AND ORTHOTICS help maintain the foot in a functionally neutral position so arch and pressure problems are relieved. Some also have absorption qualities. Small pads for the feet may also help correct foot imbalances and pressure points. They can be bought over the counter or be custom made for your feet.
  4. SKIN CARE for the feet includes creams and lotions to smooth and soften dry and callused feet. This also includes good toenail care. Proper hydration can help reduce swelling of the feet so the occurrence of hot spots and blisters is reduced. These all contribute to skin resiliency.
  5. ANTIPERSPIRANTS for the feet help those with excessively sweaty feet by reducing the moisture that makes the feet more prone to blisters. It’s another help in skin resiliency.
  6. GAITERS provide protection against sand, dirt, rocks, and grit. These irritants cause friction, hot spots, and blisters as shoes and socks become dirty.
  7. SHOE LACES and boot laces often cause friction or pressure problems. Adjusting laces can relieve this friction and pressure and make footwear more comfortable.
  8. FREQUENT CHANGES OF SOCKS AND SHOES help keep the feet in good condition. Wet or moist socks can cause problems. Changing the socks also gives an opportunity to reapply either powder or lubricant and deal with any hot spots before they become blisters. Sometimes shoes are also changed as they become overly dirty or wet.

The next post will look at how we found the right combination of blister prevention components that will work for us.

Understanding the Five Factors in Blister Formation

November 2, 2017 by · 3 Comments
Filed under: blister care, Foot Care, Footcare, General, Health, Sports 

Understanding the Five Factors in Blister Formation

This is Part III in a multi-part series on blister formation. This is a subject that still confuses many athletes. In this post, we look at the five factors that are the leading causes of blister formation.

For years, we thought blister formation was caused by heat, moisture, and friction. So, ever since the first edition, the image used to show this was a triangle with heat, moisture, and friction at its three sides. Everyone thought the three factors combined to make the skin more susceptible to blisters. That’s what was promoted in articles, running forums, and general discussion. It seemed to make sense.

Then we discovered shear, as you read in the previous Part II post. Shear encircles everything. The image shows a series of two concentric circles where shear is outside as the base on which everything else rests. The next circle contains the five factors that contribute to shear: skin resilience, bone movement, pressure, friction, and moisture. In the next post, we’ll look at the two inside additional circles: the first with the five major components of blister prevention and the innermost circle with the remaining eight minor components, which I will explain later. For now, we’ll look at the five factors that contribute to shear.

Blister formation

A view of the five factors in blister formation

1. Skin Resilience

Our skin is very resilient. However, repeated stressors to the skin, over time, can cause breakdown. The healing process can’t keep up with the ongoing trauma. This is why well-fitting shoes are important. Skin that is thin (like on the top of our feet) will abrade before it blisters, whereas thicker skin (like on the soles of our feet) is more likely to blister. We can make the skin on our feet more resilient by progressively increasing distance over time. This gradual increase of the frequency and magnitude of forces applied to the skin helps change the characteristics of the skin. Reducing calluses and using moisturizers also contributes to skin resiliency.

2. Bone Movement

As the bones in our feet move back and forth and up and down through the foot strike, and the overlaying skin remains stationary, the soft tissue layers in between stretch in a shearing motion. The more movement, relative to the skin surface, the more chance you’ll blister. When that happens, there is stretching and distortion between the inner tissues under the bone. Shoe fit is an important component in controlling bone movement. Changing your biomechanics is another way to work at reducing blister formation.

3. Pressure

Pressure is vertical force exerted against an object or surface. In this case pressure is the normal force of the foot through the foot strike. The heel comes down, the foot rolls forward onto the forefoot and off the toes. At all of these transitions, there is pressure downward, forward, and most likely side-to-side. Optimizing the fit of your footwear, correcting any biomechanical issues with an orthotic, and adding cushioning or padding can reduce pressure.

4. Friction

Mention the word friction to athletes and they most commonly think of rubbing. For instance, “My heel rubbed inside my shoe and created a blister.” It may help to know that the dictionary gives two definitions for friction. The one most people think about is the action of two surfaces rubbing against each other. Rubbing can cause abrasions to one or both surfaces, but not a blister. Forget about this definition as we talk about blisters. Let’s look at the second definition.

Scientifically, friction is defined as the force that resists one surface sliding against another. It’s easiest to view friction in one of two ways. When two surfaces slide easily against each other, we have a slippery connection—and low friction. When two surfaces resist movement against each other, we have a sticky connection—and high friction. Friction is required for shear to reach traumatic levels.

Rebecca Rushton of BlisterPrevention.com.au says it well: “There is high friction in your shoe. Surfaces are resisting movement against each other. When your skin is moist, your skin grips your sock; your sock grips your shoe. All three surfaces grip together so your foot doesn’t move around in your shoe. But with every step you take, your foot bones are moving under the skin. And while the skin is stuck the bones are moving back and forth. Everything in between is pulled and stretched. This pulling and stretching is what causes blisters. We call it shear.” Note: Rebecca wrote the forward to the 6th edition of Fixing Your Feet.

There is good friction and bad friction. High friction, as Rebecca described, is when things grip together. From this comes traction, which we need for the mechanical efficiency of our gait. Most friction is good, but when high friction causes blisters, it’s bad friction, and has to be managed—but only in that specific location. ENGO patches are an example of targeted management of friction. Now let’s look at the forces affecting friction, specifically the coefficient of friction.

4.a The Coefficient of Friction

The coefficient of friction (COF) describes the relationship between the force of friction and the normal force between two objects at which sliding is initiated. It is a number that represents the slipperiness or stickiness between two surfaces and is generally below 1.0. Within the shoe, the COF between the foot, sock, and insole can range from 0.5 to 0.9. In contrast the COF between a sock and a polished floor is around 0.2. The lower the number, the better the effectiveness in preventing blister formation.

Here’s an example. A runner may have damp feet, creating a moist condition. The COF in his case might be a 0.7. By moving away from the moist condition to either very dry feet or very wet feet, he might reduce his COF to 0.5. If his blister-causing threshold is 0.6, getting to 0.5 will reduce his chance of blistering. Moist skin is higher friction than dry or very wet skin, meaning it’s more susceptible to blistering.

Understanding the COF of materials is beneficial to knowing how shear starts and what we can do to reduce blistering. Managing the moisture on the skin, using different socks systems, and using ENGO patches are the easiest ways to reduce the COF. The COF of an ENGO patch is about 0.16 equally against a dry or wet sock, effectively reducing friction by 80%. Compare that to the COF of moleskin against a dry sock of 0.6 and a wet sock of 0.86. Again, the lower the number, the better the result.

5. Moisture

Moisture is the last factor. Increased moisture leads to an increase in friction. Beyond that, moisture does not cause blisters in any other way. Generally speaking, a lower COF is achieved with dry socks compared to wet. Some degree of moisture control can be gained with moisture-wicking socks, antiperspirants, powders, and some special lubricants. Our feet have approximately 250,000 sweat glands that can produce continuous moisture, without factoring in sweat produced though an increase in body temperature as we engage in physical activity. When active, most athletes have feet that are always damp from moisture. Moisture can also occur from stream crossings, rain, and puddles, as well as from pouring water over our heads to cool us down, which runs down our legs into our shoes.

Other Factors

There are three additional factors worth mentioning, but they are not important enough to warrant lengthy explanations or inclusion on the chart. The first is heat. Heat is not a factor in blister formation, but many athletes equate heat to causing blisters. Heat produces moisture as the feet sweat, leading to a higher COF and an increase in friction levels. But heat does not cause blisters in any other way. The second is repetition. We can minimize the chance of blisters by reducing repetitions. This can be done by shortening the length of your activity, reducing the level of intensity, and changing the frequency of your activity. But not many athletes will stop running or hiking—so there’s little point in talking about reducing repetitions.

The third factor is shear absorption. The less shear absorption in your footwear, the more pressure and friction your skin has to absorb—and that means more chance of blisters. Most of this is covered in cushioning components like socks and insoles as they work to reduce pressure and absorb shear.

The next blog post will look at the components of prevention.

Understanding Shear

This is part II of a series on blister formation and prevention. If you’ve missed the first post, I encourage yo to go back and read it to get a foundation on blisters. Here the link: Blister Formation.

In this part II, we’ll look at shear. For years we didn’t understand the concept of shear and its effect on blister formation. So let’s start with a story.

In Fixing Your Feet I tell the story of a runner at Badwater whose feet I patched. In short, he had run 90 miles of the 135-mile race, on pavement, in extreme heat. He had Elastikon tape on both balls of the feet. His feet were hurting to the point of quitting. I replaced the Elastikon tape with smoother kinesiology tape, which allowed movement between the tape and his sock, greatly reducing the shear movement between the layers of skin and the bones of his feet. I also added a large ENGO Blister Prevention Patch on each insole under the ball of each foot. By reducing the shear level, the runner was able to finish the race with less pain. Try to picture the following: as your foot moves through its foot strike, the bones of the foot move against the layers of underlying skin—then you apply a tape that is not smooth to the skin, pull on a sock, and finally put your foot inside a shoe. The tape sticks to the skin. As you run, the foot naturally moves a bit inside your shoes.

However, the sock cannot move freely against the coarseness of the tape. The sock and tape move as one, which stresses the outer layer of skin against the inner layers. The only movement is the shearing effect between the layers of skin.

That experience was the first time I made the connection to shear, although I didn’t know it by that name. All I knew is the stickiness at the sock–shoe interface, the tape–sock interface, and the tape–skin interface—and one, or all three, had created this major problem for the runner. I never forgot the story. His skin was stuck to the Elastikon tape, the coarse tape didn’t move against his sock, and the sock didn’t move against the shoe’s insole. With the smoother kinesiology tape and the new slipperiness between the tape and the sock, the coefficient of friction was reduced and in turn shear was reduced.

Shear is a new concept for most athletes, especially as it relates to blisters. Shear is defined as a strain in the structure of a substance when its layers are laterally shifted in relation to each other. Applying the definition to the above example, shear happened between the layers of skin as the bones of the foot moved through the foot strike. The internal layers of skin were connected. But those connections can break under the stress of shear and the cavity fills with fluid—and you have a blister.

To understand shear, try this. Place the tip of your index finger against the skin on the back of your hand. Keep it stuck to the same bit of skin while you move it back and forth while. See how your skin stretches? The skin on your hand has moved against the underlying bones. That is shear that causes blisters.

Note that nothing has rubbed against the skin. Your finger did not rub the skin. J. Martin Carlson, the founder of Tamarack Habilitation Technologies, has championed shear as the cause of blisters. Tamarack has a long history of providing innovative orthotic-prosthetic componentry and materials. Their focus on friction management, especially for amputees, has won them many awards and much recognition. This knowledge in turn led to the creation of a new product that can be applied to footwear to reduce high friction levels and, in turn, the shear that leads to blister formation: ENGO Blister Prevention Patches.

Shear in Action

After watching a video on Tamarack’s website, I understood more about shear in action. The video showed a cutaway on the heel area of a shoe, showing the sock and foot inside moving through a foot strike motion. In one video, the cutaway showed a sock and foot on an insole where there were high levels of friction. The sock and foot were distorted as they were held against the insole. It was as if they were stuck together. In another video, the sock and foot were on an insole with an ENGO patch underneath. No distortion occurred as the sock and foot moved easily through the foot strike, over the slippery surface of the ENGO patch.

It’s important to grasp how shear happens. As described above, shear results in distortion occurring between the skin and soft tissues underneath. This shear distortion is what causes blisters. The bones in our feet move back and forth as they move through each foot strike. When the skin at the bottom of the foot is stuck by high friction (stickiness) to the sock and shoe, the middle tissues are distorted. When this is repeated over and over, traumatic levels are reached and a blister forms. This distortion can happen anywhere on the foot: in an up-and down motion in the heel, the sides of the foot, and between toes; in a side-to-side motion at the ball of the foot, under the heels, and at the bottom of the toes; and in rotation as the foot moves through its foot strike. As we walk, run, and pivot in our shoes, the surface of our skin incurs a shearing force.

Certain amounts of shear are normal, and our feet can deal with a lot. However, with repeated traumatic levels of shear, blisters will develop. How much is too much? It varies from person to person, and some people are simply more blister-prone than others.

Part III will look at the five factors of blister formation.

Blister Formation

October 14, 2017 by · Leave a Comment
Filed under: blister care, Foot Care, Footwear Products, Health, Sports 

This is the first in a multi-part series on blister formation and prevention. Subsequent posts will focus on various part of the blister process. Too many people do not understand how blisters form, some even think they are a natural part of the running or hiking experience.

Blisters are the result of shear trauma to the skin. When running, every step is “repetitive loading” as the foot moves through the foot strike. The whole of the body’s weight is put on the skin and inner tissues, onto the bones and joints, up the leg, into the knees and hips, and into the pelvis and spine. For now, let’s focus on the foot. The skin can take a lot of repetitions without a problem, but once skin and tissue damage reaches a painful level, the trauma is escalating rapidly.

Repetitive loading has two components. The first is a vertical loading to the surface of the skin and by itself is relatively harmless. The second is a repetitive friction loading parallel to the surface of the skin. The two combine to create shear stresses within the skin. When these shear stresses exceed a certain level, micro tears begin to form within the third layer of tissue. As more repetition occurs, more micro tears appear and existing tears grow. These tears in the tissue form a cleft parallel to the skin’s surface. The cleft fills with serous fluid and a blister has formed—caused by shear stressors. This typically occurs in the stratum spinosum, the inner fourth layer of the epidermis that is the least resistant to shear.

If the blister is deep or traumatically stressed by continued running or hiking, the serous fluid may contain blood. When the serous fluid lifts the outer layer of epidermis, oxygen and nutrition to this layer is cut off and it becomes dead skin. This outer layer is easily burst. The fluid then drains and the skin loses its natural protective barrier. The underlying skin is raw and sensitive. At this point, the blister is most susceptible to infection.

Rebecca Rushton, an Australian podiatrist and the author of The Blister Prone Athlete’s Guide to Preventing Foot Blisters, has studied extensively about blister formation. She has identified four requirements for shear that cause foot blisters to form:

  1. Skin resilience: The skin on our feet is, by its very nature, susceptible to blister formation. Repeated gradual exposure to shear can improve the skin’s ability to withstand shear stress. Often times the skin is stressed by a sudden increase, or an increase over many days. Examples include increasing one’s mileage too quickly and doing more than normal in a multiday event.
  2. Moving bone: Bones within the foot move throughout the foot strike. The more they move relative to the skin’s surface, the higher the shear stress created, and the more likely you are to develop a blister. An example is the movement of the heel bone underneath the skin as it moves up and down in the shoe’s heel counter.
  3. Repetition: It’s the repetitions throughout the foot strike that increase the odds of a blister forming. An example is studies showing that runners in a multiday event blister more as the race progresses.
  4. Friction and normal force: The levels of friction and pressure determine the amount of shear that impacts the skin.

It’s worth talking about how blisters will deroof—when the stop layer of skin is torn off the top of the blister. Consider a back-of-the-heel blister. A blister has formed because the heel bone has moved up and down while the outer skin has remained fixed inside the sock and shoe. The shear stressors, as described previously, have caused the blister. With repeated levels of movement against the skin on the back of the heel, the skin can be rubbed over and over. This is what causes abrasions. When the forces that cause blisters combine with forces that cause abrasion, the skin is stretched past normal levels and is torn off.

In reality, some people are more blister-prone than others, irrespective of the amount of training and preparation. In spite of having done everything right, the shear strength of their skin is going to be lower than others—no matter what they do. They are simply blister-prone. For others, some of this has to do with the training that they do in preparation for races. It’s quite common at races to see lead runners come through aid stations without any blister problems. They typically have conditioned their feet through extensive training. But as the race progresses, the middle- and back-of-the-pack runners enter aid stations with a lot of blister problems. They typically have put fewer miles on their feet and, in some cases, have made poor choices about footwear and foot care.

This is the first in a multi-part series on blister formation and prevention. The material is extracted from Fixing Your Feet, 6th edition.

Doc on the Run

September 19, 2017 by · Leave a Comment
Filed under: Foot Care, Foot Care Products, Footcare, Health, Sports 

I recently attended a conference where I had the opportunity to meet Dr. Christopher Segler. He’s an award winning foot and ankle surgeon and podiatrist who is a runner and 15-time Ironman finisher. His practice is in San Francisco and the Silicon Valley in California. His focus in on helping runners, triathletes, and athletes to stay active and keep running.

Christopher is unique in that he is literally the Doc on the Run – i.e., he makes house calls. His website is a wealth of information on everything foot related, his Runner’s D.I.Y. advice, products, videos, courses, and ways to connect with him. Even if you don’t live in the area, you can get a consultation over the phone or through Skype.

Doc on the Run

Take a look at his Doc on the Run website and read some of the articles. His Runner’s D.I.Y. page has information on arch pain, ball of the foot pain, ankle sprains, and five other areas. The Advanced Treatments page has information on Platelet Rich Plasma injections, stem cell therapy, neuroma treatment toenail fungus treatment and more. Many pages have videos.

There’s also a Doc on the Run podcast with 58 episodes. Many are under 30 minutes in length. Show topics include sprained ankles, neuromas, tendon injuries, shin splints, toe and toenail injuries, plantar fasciitis, and more. You can subscribe to his podcast in iTunes or on his website to receive notice of new episodes. If you haven’t discovered podcasts yet, Christopher’s show is an excellent place to start.

Finally, he has a book Runner’s Heel Pain: Self-Diagnosis and Self-Treatment available as an ebook.

I encourage you to check out the Doc on the Run website and podcast. Every athlete at some point suffers from injuries. Dr. Christopher Segler will help you get healed and keep on running.

He also has a Facebook page and videos on YouTube.

The Year’s Best Blister Horror Story

You may have seen the news articles either in your newspaper, or on Facebook, or on TV. Let me paint you a word picture of some of the headlines and quotes:

  • Blister sparked tears
  • “I got a really bad blister.”
  • “My mind was ‘blocked with pain’ of a blister.”
  • Pain and tears
  • Blister caused meltdown

Marin Cilic let the tears come midway through the second set after calling for medical attention for a nasty blister on his left foot. The former US Tennis Open champion had tried to play through the pain, but couldn’t stop Federer from winning the tournament. Cilic said, “I got a bad blister in the semi-final against Sam Querrey. Fluid just came down under my callous in the foot.” The medical staff helped him over a period of 30 hours and did as much as they could. He said, “I still felt the pain. Every time I had to do a reaction fast, fast change of movement, I was unable to do that.” Cilic was challenged emotionally because of everything he had gone through in the months before Wimbledon. “It was very, very difficult to deal with it. It didn’t hurt so much that it was putting me in tears. It was just that feeling that I wasn’t able to give the best.” Here’s the full story.

Wimbledon 2017: Devastated Marin Cilic Reveals Blister Sparked Tears

What did this cost Cilic? It cost him the championship at Wimbledon and the fame and fortune that goes with it. Putting it into language that athletes would understand, If this had been you, it could have cost you a completion of a hundred mile race, an adventure race win, a marathon win, a through hike, and more.

So here’s what happened. We know that Cilic had a callus on the ball of his left foot. A blister developed under the callus, and then popped. A fluid filled blister hurts and when it’s on a pressure point area of the foot, it hurts even more. Then with the fluid removed, the blister’s roof moves against the inner layer of raw skin, causing even more pain. Movement, especially when doing sudden pivots and push-offs, as required in tennis, becomes impossible. That’s it. One blister. But a blister in a vital spot – at the head of the metatarsal at the base of the large toe on the left foot can ruin your day – or your chance for the 2017 Wimbledon trophy.

In the picture you can see white stuff on the bottom of Cilic’s foot. That’s tape residue from the layers of tape they put on his foot. The residue builds up into a sticky mess and can become an irritant. Look closely and you’ll see a callus or blister just under the ball of his big toe. That’s a typical callus area too and I’d bet he had a thick callus there. Cilic mentioned fluid that came out from under the callus. Try as they could, the doctors and medics were unable to patch his foot so he could play the way he needed to play. Since his play was compromised, he ended up losing.

So what’s the lesson here?

  1. Callus buildup is bad. It’s one of my main things I talk about. Calluses. Spend the time it takes to reduce your calluses. If Cilic did not have a callus, he might not have developed a blister.
  2. Treat it right from the start. We can only speculate what treatment Cilic received. How did they lance the blister? Did they get all the fluid out? Did it refill? What did they put over the callus and blister? Did the blister extend beyond the callus? What kind of tape did they use? What did he do to his foot during the 30 hours? How many times did they try to tape it. Why didn’t they remove the tape residue?
  3. Was this a recurrence? In other words, had he had a blister in the same place before?
  4. What was the surface of his insoles like? Coarse and rough? Smooth? Did they change insoles?
  5. What kind socks was he wearing? Did he change to a different pair as the injury progressed?

What would I have done? My treatment is based on what I read through the news stories and saw in the pictures.

  1. I would have checked his insoles and if they had a rough surface, I would have replaced then with a pair that had a smoother surface.
  2. I would have put a large ENGO Blister Prevention Patch on the insole under the callus and ball of the foot. This would have reduced the friction dramatically.
  3. If the callus over the blister is rough and coarse skin, I’d file it down to remove some of the coarseness and bulk.
  4. I would have made sure there were at least three lanced holes in the blister, in spots were pressure through the foot strike would have forced fluid out. And made sure all the fluid was out.
  5. I’d put a small dab of antibiotic ointment over the blister and apply a strip of kinesiology tape over the whole ball of the book, making sure the skin was clean, with a tincture of benzoin base and an added strip of benzoin to the tapes edges.
  6. I’d then add two figure 8s from Hypafix or Coverall tape between the toes to anchor the forward edge of the kinesiology tape at the base of the toes.
  7. Finally, roll the socks on the foot to avoid pulling any edges of the tape loose.
  8. Optionally #1, If the pain was almost unbearable, I would have applied cushioned adhesive felt over the ball of the foot and then the kinesiology tape over that.
  9. Optionally #2, I would have the athlete wear a double layer sock or two light weight socks to allow for movement between the two socks layers and reduce pressure on the ball of the foot.

Over the years, I have found most doctors, nurses, physical therapists, and even podiatrists, do not know how to patch blisters on athlete’s feet in order to get them back into the race or event.

I know I was not courtside, and don’t know what Cilic’s medical people saw. But the above treatment plan is still what I would do regardless of other things. You are welcome to weigh in on what you think.

Bad Toenails at Western States

July 7, 2017 by · 2 Comments
Filed under: blister care, Foot Care, Footcare, General, Health, Sports, toenails 

I’m taking another opportunity to share a few pictures from the Western States 100 two weeks ago. The pictures were taken at the finish line. They are important because it’s very hard to get runners to learn how to manage their toenails. Maybe the two pictures will help.

The tops of bad toenailsThe first picture is taken looking down at the tops of the runner’s two great toes. Notice the apparent forward rough edge of the toenails. See the blood at the back of the nail, at the base of the nails? In this instance, the toenails were pushed backwards into the nailbed and into the cuticle of the nail and the nail folds that support the nail at the rear and sides.

The constant trauma to the toes with the toenails being pushed backwards, caused blood to form at the base of the nail. The blood then spreads to the inside of the toe and under the nail. In the second picture, you can see blood all along the inside of the toe and moving under the toe and forward over the tip of the toe.

The front of bad toenailsThe downhills, or a shoe too short in either length or height of the toe box were all contributing factors. But the real cause, in my opinion, was the toenails that are too long and not trimmed short enough and then filed smooth.

In August 2005, I wrote a blog post about Trimming Toenails – It’s Not That Hard. Here is what I wrote:

How hard can it be to trim your toenails? I guess for a lot of folks, it’s a huge deal and something they never do. In all the years I have been patching feet, I have observed that untrimmed toenails are the number one cause of problems leading to toe blisters and black nails. Socks will catch on nails that are too long or that have rough edges. This puts pressure on the nail bed. Nails that are too long are also prone to pressure from a toe box that is too short or too low.

So what are some tips to keeping your toenails under control? Toenails should be trimmed straight across the nail—never rounded at the corners. Leave an extra bit of nail on the outside corner of the big toe to avoid an ingrown toenail. After trimming toenails, use a nail file to smooth the top of the nail down toward the front of the toe and remove any rough edges. If you draw your finger from the skin in front of the toe up across the nail and can feel a rough edge, the nail can be filed smoother or trimmed a bit shorter.

Use a regular nail file from your drug store, you know, those cheap “use it a few times and toss it” file. Better yet, invest a few bucks in a nice metal file that will last a long time and serve you well. If you need clippers, there are regular large clippers and for thick nails there are nippers and scissors made exclusively for toenails. If your local drug store or pharmacy doesn’t have them, check out FootSmart for a great selection.

A little bit of care in toenail trimming goes a long ways in making your socks last, and in preventing toe blisters and black toenails.

In the case of the runner at Western States, good toenail care could have prevented his blood blisters.

I have repeatedly written about toenails and how to take care of them. It’s one of the things I stress with runners. It’s so easy to do and only takes a few minutes. At our aid stations and the finish line, we saw many runners with bad toenails.

Tonya Olson, a physical therapist who does amazing foot care too, has helped at Western States for many years. She’s worked Michigan Bluff, Foresthill, and then we work the finish line together. When we see runners with toenail blisters or untrimmed toenails, we look at each other to decide which one of us will give the runner “the toenail talk.” You don’t want to be on the receiving end of the “toenail talk” because we make you feel guilty about your lack of quality toenail care. Again, it’s so simple and can save your race.

If you missed last week’s blog post about the condition of feet at Western States, here the link to the post: Feet at Western States.

Next week I’ll be in Death Valley for the 135-mile Badwater Ultramarathon. We’ll see what feet are like there.

Bad Toenails at Western States

July 7, 2017 by · 2 Comments
Filed under: blister care, Foot Care, Footcare, General, Health, Sports, toenails 

I’m taking another opportunity to share a few pictures from the Western States 100 two weeks ago. The pictures were taken at the finish line. They are important because it’s very hard to get runners to learn how to manage their toenails. Maybe the two pictures will help.

The tops of bad toenailsThe first picture is taken looking down at the tops of the runner’s two great toes. Notice the apparent forward rough edge of the toenails. See the blood at the back of the nail, at the base of the nails? In this instance, the toenails were pushed backwards into the nailbed and into the cuticle of the nail and the nail folds that support the nail at the rear and sides.

The constant trauma to the toes with the toenails being pushed backwards, caused blood to form at the base of the nail. The blood then spreads to the inside of the toe and under the nail. In the second picture, you can see blood all along the inside of the toe and moving under the toe and forward over the tip of the toe.

The front of bad toenailsThe downhills, or a shoe too short in either length or height of the toe box were all contributing factors. But the real cause, in my opinion, was the toenails that are too long and not trimmed short enough and then filed smooth.

In August 2005, I wrote a blog post about Trimming Toenails – It’s Not That Hard. Here is what I wrote:

How hard can it be to trim your toenails? I guess for a lot of folks, it’s a huge deal and something they never do. In all the years I have been patching feet, I have observed that untrimmed toenails are the number one cause of problems leading to toe blisters and black nails. Socks will catch on nails that are too long or that have rough edges. This puts pressure on the nail bed. Nails that are too long are also prone to pressure from a toe box that is too short or too low.

So what are some tips to keeping your toenails under control? Toenails should be trimmed straight across the nail—never rounded at the corners. Leave an extra bit of nail on the outside corner of the big toe to avoid an ingrown toenail. After trimming toenails, use a nail file to smooth the top of the nail down toward the front of the toe and remove any rough edges. If you draw your finger from the skin in front of the toe up across the nail and can feel a rough edge, the nail can be filed smoother or trimmed a bit shorter.

Use a regular nail file from your drug store, you know, those cheap “use it a few times and toss it” file. Better yet, invest a few bucks in a nice metal file that will last a long time and serve you well. If you need clippers, there are regular large clippers and for thick nails there are nippers and scissors made exclusively for toenails. If your local drug store or pharmacy doesn’t have them, check out FootSmart for a great selection.

A little bit of care in toenail trimming goes a long ways in making your socks last, and in preventing toe blisters and black toenails.

In the case of the runner at Western States, good toenail care could have prevented his blood blisters.

I have repeatedly written about toenails and how to take care of them. It’s one of the things I stress with runners. It’s so easy to do and only takes a few minutes. At our aid stations and the finish line, we saw many runners with bad toenails.

Tonya Olson, a physical therapist who does amazing foot care too, has helped at Western States for many years. She’s worked Michigan Bluff, Foresthill, and then we work the finish line together. When we see runners with toenail blisters or untrimmed toenails, we look at each other to decide which one of us will give the runner “the toenail talk.” You don’t want to be on the receiving end of the “toenail talk” because we make you feel guilty about your lack of quality toenail care. Again, it’s so simple and can save your race.

If you missed last week’s blog post about the condition of feet at Western States, here the link to the post: Feet at Western States.

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