Filed under: blister care, Foot Care, Foot Care Products, Footcare, Footwear, Footwear Products, Health, Sports, toenails
The seven tips below are written for the Primal Quest Expedition Adventure Race starting next week. They are also applicable to any race you may have coming up.
Primal Quest is less than two weeks away and here are seven things you can do to improve your chances of finishing with healthy feet.
1. Wear the best fitting shoes you can. Have a bit of space in front of your longest toe and enough height in the shoe’s toe box to avoid squishing the toes from the top.
2. Bad toenail care can result in toe blisters and black toenails, where fluid or blood is under the nail. Trim your toenails short and then use a nail file to smooth the tip of the nail. File the nails from the top over the edge down toward the tip of the toe. The goal of the trimming and filing is to remove any rough or sharp edges. File the nails so when you run your fingertip up and over the tip of the toe no rough edges are felt. It’s even better to file the nail so that no tip of the nail is felt. If you have thick nails, file the top of the nail down to reduce its thickness.
3. Any time you can, remove your shoes and socks to dry and air your feet. Your feet will be wet from water disciplines, stream crossings, cooling yourself off by pouring water over yourself, and simply sweaty feet. When stopping to eat or rest, remove your shoes and socks. Lay your socks in the sun to dry and switch to a clean dry pair if possible. Issues caused by wet feet will multiply over time and can end your race or at the least, result in extremely painful feet.
4. Do everything in your power to prevent and reduce maceration. This means not letting water poured over your head get into your shoes by bending over before dousing yourself. If means following the tips outlined in # 2 above. Use a moisture-controlling agent to help prevent the skin on the bottoms of your feet from macerating. Several include Desitin Maximum Strength Original Paste (available at drug stores, Walmart, etc), zinc oxide, Chafe X, SportsSlick, Trail Toes, and RunGoo. Apply liberally and before all water segments to help prevent damage to your skin. Once serious maceration happens, only drying your feet and letting them air, with the help of powder and warmth, will reverse the condition. If left unchecked, the skin can fold over on itself, split open, and tear layers of skin off the bottom of your feet.
5. Use gaiters to prevent pebbles and rocks, trail dust, and other debris from getting inside your shoes and socks. These become irritants and can lead to hot spots and blisters.
6. Take care of small issues before they become larger problems. Lance and drain small blisters whenever you feel them to keep them from becoming larger. Put a dab of ointment over the blister and then apply a strip of tape over the top to protect the skin.
7. Finally, make sure you have the supplies to treat your feet out on the course. Waiting to get to a TA to repair a blister can make a small problem much larger.
Filed under: blister care, Foot Care, Foot Care Products, Sports
I have often mentioned the website BlisterPrevention.com.au as a great source of information on blister care. Rebecca Rushton, manages the website and is on top of developments in the prevention and care of blisters. She’s a podiatrist in Australia – and a friend.
Through research and looking at the mechanism of how blisters form, Rebecca has changed some old theories of what causes blisters. Heat, moisture, and friction were always considered the three contributors of blisters. Further consideration has found that shear is a major factor. Shear and friction combine to cause blister formation.
I want to quote a blog post by Rebecca about Healing Foot Blisters Faster to help you understand more about friction and shear.
“You know friction is responsible for friction blisters. But I bet you think friction is rubbing. It isn’t. Friction is about grip. High friction means two surfaces grip together. Low friction means they don’t … they’re slippery.
“Here’s how friction is responsible for foot blisters … There is high friction in your shoe. There just is. This means your skin grips your sock; and your sock grips your shoe. All three surfaces grip together so your foot doesn’t slide around in your shoe.
But with every step you take, your bones are moving around under the skin. And while the skin is stuck and 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. And it needs high friction to get anywhere near blister-causing.”
With this opening, Rebecca starts to explain the effect of shear and friction on blister formation. She talks about cutting friction levels, especially when a blister develops, and gives examples of six friction reducers. Some of these are better than others.
We have always tried to reduce friction in both preventing blisters and when treating blisters. As Rebecca says, and I support, “Otherwise all that stretching (shear) continues at the blister base while it’s trying to heal. Making it hurt more. And taking longer heal.”
So take a moment and click on the Blister Prevention link and read Rebecca’s full blog post. While you are there, I encourage you to subscribe to her email list.
Filed under: blister care, Foot Care, Foot Care Products, Health
A while back I was sent a sample tube of Blue Steel Sports Anti-Chafe Cream. It’s another entry into the marketplace of blister and chafe prevention products – needed by many athletes.
Blue Steel Sports Anti-Chafe Cream is a white non-sticky and non-greasy cream that spreads evenly and leaves a protective smooth, almost silky feel to the skin. Unlike some creams or lubricants, I did not have to wash my fingers after applying it to my skin. It’s not oily. It will wash off with soap and water and will not stain your clothes.
This cream can be used by athletes, whatever their sport. It has a great following by cyclists, but is perfect for runners, walkers and hikers. Use it on your feet – between your toes and on your heels, anywhere you typically develop hot spots or blisters. If you are doing a long race or event, you might want to pack a small amount in a Ziploc bag for a second application if you feel it necessary. While it will not sweat off, if you are ding a day long race, a second application could be helpful. It can be used on underarms, inner thighs, and anywhere in your groin or backside areas. It works well on sensitive skin areas and will not burn or sting. Cyclists can also apply it directly to the chamois in their bike shorts.
Blue Steel Sports Anti-Chafe Cream is available in a 3.3 oz tube and smaller single use packs. A little bit of the cream goes a long ways.
The cream contains Tree Tea Oil, which has nice healing properties. It also contain silicone, which helps with moisture and perspiration control, an important part of foot care for many athletes.
Here’s a report from a friend I asked to try the cream. “I got a chance to use Blue Steel Sports Anti-Chafe Cream cycling 46 miles on Friday. Cycling was the first sport on it’s list of uses, and it says ‘Apply directly to skin on ANY areas prone to chafing’, and on cyclists that would be the whole crotch zone, which is embarrassingly where I have a problem on long rides with lots of hills. You can also apply it after an activity to calm irritated skin, so I assumed it must be for sensitive areas. It was not uncomfortable to apply, and has a pleasant herbal scent, and was effective at eliminating crotch chafe for me, even though I rode 46 miles. I had no need to apply it afterwards and it did not stain my clothing. I used it only once, but I give it a ‘Thumbs up’!”
Check out some of the testimonials on their website and you’ll find someone who is doing your sport and has had success with the cream.
I recommend trying Blue Steel Sports Anti-Chafe Cream for your activity. I am a strong believer in trying products to find the best for your feet (and in this case, other body parts). I think Blue Steel Sports Anti-Chafe Cream is a winner.
I have no financial interest in Blue Steel products.
Filed under: blister care, Foot Care, Foot Care Products, Footwear, Footwear Products
Occasionally I see runner’s shoes that have wear holes in the material in the heel counter. This picture from Dan shows his shoes with holes to the outside of center on both heels. I emailed the following suggestion.
I’d try an ENGO Back of Heel Patch. They are made to shape to the curve of the back of the heel counter. Put them in when the shoe is dry. Rub them a bit in a curving motion to help them form to the shape of the shoe. Then peel off the paper backing and apply from the center outwards to the sides. Rub well so they adhere to the shoe’s material. You could also try the large ovals if the hole is small. The blue ENGO patches are very slick and can take a lot of wear. Once the blue wears down to expose white, replace the patch. Sometimes the holes are on the sides of the heel.
Last summer at Western States, I had a runner whose shoe was rubbing her heel raw. You can see from the image that she has a prominent heel bump. This, of course, contributed to her problem. This is the kind of problem one needs to plan for before it becomes a major issue – especially at the event the magnitude of Western States.
We decided to cut a notch out of the outside of her shoe’s heel. This allowed the back of the shoe to spread apart for her large heel bump. Then I applied an ENGO Back of the Heel Patch to the inside of the shoe’s heel counter. This provided some protection to her heel bump.
The large ENGO ovals can also be used when there is a small area to be covered.
I have been a fan of ENGO Blister Prevention Patches since I first discovered them years ago. The ovals are perfect for the common areas at the side of the heel where blisters form at the junction of insole and heel counter. The large rectangles are great to put on insoles underneath the ball of the foot, another common problem area.
Check out the ENGO website for more information. ENGO products are available through Zombierunner. If you are in Australia or New Zealand, ENGO products are available through Rebecca Rushton’s Blister Prevention website.
Disclosure: Tamarack Habilitation Technologies supplies me with ENGO Patches as I need them for races.
Filed under: blister care, Foot Care, Foot Care Products, Health, Sports
Foot Kinetics recently introduced several new products designed to reduce blister formation. Carl and Rick, founders of Foot Kinetics, developed HikeGoo, RunGoo, WalkGoo, and SilkStep foot creams for preventing blisters and providing moisturization. The products help avoid foot problems by forming a friction-free layer between the skin and sock. This protective layer reduces rubbing and friction, working on a variety of foot problems including blisters, callus formation, soft tissue bruising, and sore feet. Each formulation is different and contains a balance of hard wax, lanolin, and natural vegetable waxes to moisturize and protect feet from abrasion and foot fatigue.
The protective foot creams are formulated for specific activities and footwear. The relative percentage of hard versus soft waxes in each product’s formulation enables it to perform optimally for that activity. The more hard wax in the formulation, the longer the product stays on the skin’s surface and the slower it absorbs. HikeGoo has the hardest wax and will last in the harsh environment of a boot on an all-day climb. RunGoo has the hard wax persistence of HikeGoo but also some added soft wax moisturization. The higher percentage of soft waxes in the foot cream, the greater the absorption and dry skin moisturization. SilkStep has the softest waxes and is optimized for moisturization.
Rather than repelling moisture or attempting to block sweat, the unique formulations actually absorb sweat and moisture to become even more effective in reducing friction between the skin and sock. This is why Foot Kinetics say they are highly effective in both dry and wet conditions to protect feet from blisters, callus formation, and skin damage.
Why it works
According to the folks at Foot Kinetics,“Our barrier creams stick around much longer than any other blister prevention or anti-chafe product on the market. They contain a high percentage of specialty hard waxes that are blended into the emulsion and make it persistent…. make it stick around all day to provide a protective layer that reduces rubbing, friction, calluses and blisters. Most other anti-chafe and blister prevention products are dimethicone-based. They are OK for thighs and chest but are too thin to stand up in the harsh environment of a shoe and you can’t apply enough to last all day.” Click on the image above for a larger view.
Foot Kinetics put a high concentration of hard wax in the HikeGoo, RunGoo, and WalkGoo emulsions and then figured out how to adjust the ‘rheology’ (deformation and flow) of the product so that it can flow out of a tube. They point out no one else has been able to do this.
They point out the other key to the success of their Goo products is their ability to last over an entire day because of the balance of lanolin alcohol in the emulsion. The balance allows it to absorb water or excess sweat and makes the emulsion ‘slipperier’. Moisture, usually present between the skin and sock, contributes to blister formation, and the lanolin alcohol balance make the skin slipperier to help keep blisters from forming.
RunGoo Protective Foot Cream prevents blisters by providing a friction barrier between the skin and sock. RunGoo contains lanolin and a balance of both soft and hard waxes to create a foot care cream that protects feet from skin damage. It is effective in eliminating blisters and calluses in traditional, barefoot style running shoes, and hiking boots. RunGoo is available in 5.5 and 3-ounce tubes.
HikeGoo Protective Foot Cream is very similar to RunGoo and provides a friction barrier between the skin and sock that protects feet from blisters, nerve abrasion and foot fatigue all day. High melting point waxes slow its skin absorption to create a protective layer that stays on the skin’s surface and is highly effective in helping prevent blisters. HikeGoo absorbs completely by days end and socks easily wash clean. HikeGoo is available in 5.5 and 3-ounce tubes.
WalkGoo Protective Foot Cream is a thinner compound and is good for feet because it protects and moisturizes during sport walks or while on the job. WalkGoo’s friction-free formulation reduces rubbing by including Jojoba, Mimosa, and Sunflower waxes which stay on the skins surface longer to help prevent blisters, calluses and nerve abrasion while softening and smoothing cracked heels and rejuvenating dry feet. A single application lasts all day and absorbs cleanly. WalkGoo is available in 8 and 3-ounce tubes.
SilkStep Protective Foot Cream has the highest percentage of Jojoba, Mimosa and Sunflower waxes of all their protective foot creams. It absorbs slowly providing a protective layer on the skin.
You can find all their products at the Foot Kinetics website.
The Goo products all have the same basic compound, but the amount of hard and soft waxes as well as hydration varies in each formula. Some are thicker than others and will stay on the foot for longer periods of time.
The Foot Kinetics Goo products are advertised as lasting, “…for the entire race, workout, run or game.” You need to determine if that works for your event. There’s a big difference between a 12-mile hike, a marathon, a 100-mile run and a 24-hour run. Try the Goo to see how it holds up on your skin during your events, reapplying it if necessary. If using it in events with sand and grit, cleaning the foot and then reapplication will probably be necessary.
Applying the Goo
To apply, with one or both hands, squeeze the tube firmly to get the cream started out the hole. You may have to squeeze hard, especially if in cold weather. After this initial squeeze the cream will come out more easily. Continue squeezing the tube while rubbing the applicator over your foot taking care to thickly cover problem areas such as heels, bunions, toes and the soles of your feet. Don’t worry if the coverage is uneven or lumpy. This is normal. Starting at your toes with your sock mostly inside-out, roll or pull your sock on and up over your heel. Don’t drag your sock on as this could wipe away some cream leaving exposed areas. If you are going to be engaged in your activity for a long time (i.e. hours), a thicker layer provides optimum protection.
Foot Kinetics protective foot creams are to be used only on closed healthy skin and not open wounds.
The Foot Kinetics website has a testimonials page describing how athletes have used the their products.
I used HikeGoo on several occasions. The compound is thick. Getting the initial squeeze out of the tube is challenging, as they describe. The design of the applicator gives you a generous amount of the Goo to spread on your feet. That’s how the Goo is meant to be used. If you are used to rubbing a small smear of BodyGlide or other lubricant on your skin, You’ll have to get used to the Goo. The hard waxes keep it thick and that’s how you should use it. Many lubricants go on and you have a hard time knowing they are there. When applied properly, you’ll feel the Goo, and know it’s working.
The Goo reminds me of Desitin Ointment – the stuff used on baby bottoms. The consistency in thickness is almost the same. It’s white so you see exactly where you have applied it and how much is on your skin. I like that aspect of the Goo.
I also like the two sizes of tubes; making it easy to carry a small tube in a pack, while keeping the larger tube in your foot care kit.
There’s always room on the shelves for more lubricants. This is one you’ll want to try. When I try products, I often use one on one foot and another (or nothing) on the other foot. I feel that gives me the best opportunity to fairly test the products. I’ve done that with shoes and socks too.
Give RunGoo or HikeGoo a test. See how the formula works for you. Use your regular lubricant on one foot and the Goo on the other. Then do a long run or hike, and see which your feet like the best. They can be ordered from the Foot Kinetics website and from Amazon.
Disclosure: I was supplied several samples of the Goo products to test. RunGoo, HikeGoo, WalkGoo and SilkStep are trademarked names of Foot Kinetics.
Back in May I posted an article about Training With Wet Feet. My being invited to work on the medical team at the Jungle Marathons in Vietnam and the Amazon prompted the article. While the Vietnam race had to be cancelled, the Amazon race is happening – in a bit over two weeks.
As I wrote in that article, it was long felt the best way to manage your feet was to keep them as dry as possible. This was more and more evident as Denise Jones and I worked the Badwater Ultramarathon in the heat of Death Valley each July. Runners who kept their feet dry typically finished better than those who had wet feet. This was also based on our experiences at Western States and other events.
Then came the invite to help at the Jungle Marathons.
The Jungle Marathons are run by Race Director Shirley Thompson and the Medical Team Manager is Vicky Kypta. They found their runners had a better race when they trained with wet feet. As part of their instructions to their race participants, they stress the importance of training with wet feet.
The reason for this is the Jungle Marathons are wet. Very wet is typical in the jungle. Whether through rivers or streams, the Amazon is full of water.
When I am helping runners at the race in early October, I will be closely monitoring the condition of their feet. I expect runners will use lubricants and other products to control the moisture, or powder, socks, well-draining shoes, and maybe a few home-grown tricks.
Over the past few months, I have shared some of the findings by Rebecca Rushton, a podiatrist from Australia. In her Blister Prevention Report, she talks about managing moisture control. She supports her report with studies from medical and other professional journals. What she found through the studies is that you could reduce the incidence of blisters by keeping the skin either very dry or very wet.
Rebecca writes that, “… the very high or very low skin moisture strategies aim to reduce the coefficient of friction value between the sock and the skin to below blister-causing levels.”
The Coefficient of Friction
The coefficient of friction (COF) is the number that represents the slipperiness or stickiness between two surfaces. According to studies, this number is generally below 1.0. Inside the shoe, the COF between the foot’s skin, and the sock and insole can range from 0.5 and 0.9. Compare this to the COF between a sock and a polished floor – about 0.2.
In Rushton’s report, she illustrates this with an example of a runner whose feet sweat a lot. His socks become damp, creating a moist condition. The COF in this case might be 0.7. By moving away from a moist condition to either very dry or very wet, the runner might reduce the COF to 0.5. If the runner’s blister-causing threshold is 0.6, getting to 0.5 will reduce his chances of blistering. Reducing the COF between your skin and socks/insole combination is important to having healthy feet.
Moist skin produces higher friction than very dry or very wet skin. Whether skin is dry and becomes moist through sweat or through a water moisture source, or is very wet and becomes moist through heat or simply drying out, when it hits this middle stage, it becomes more susceptible to blistering.
Very Dry Skin
Drying the skin can be done with powders, antiperspirants or other drying agents, used by themselves or in conjunction with moisture control socks. Keeping the skin very dry is tough because our feet sweat naturally. Humid or hot conditions can also make it hard to keep the skin dry. Dumping water over your head to cool yourself can result in water running down your legs into your shoes – defeating your efforts to keep your feet dry. Airing your feet with shoes and socks off can help. If you use powders, make sure it is high quality and does not cake, which can be an irritant. When counting on any of these methods to keep your skin dry, you mush also have shoes that allow moisture to escape. That may include shoes with mesh uppers and drain holes in the arches and heels.
Very Wet Skin
Increasing skin moisture leads to very wet, lubricated skin that reduces the skin’s coefficient of friction. This can be through the use of a lubricant and or by simply having wet feet. The thing to remember is that over time, 1-3 hours, friction will increase as the lubricant is absorbed into the socks – so ongoing application is required.
Remember too what happens to your skin when you spend too much time in the water. It becomes weaker and less able to resist trauma on wrinkly skin. In extreme cases, the skin can fold over on itself and split. Severe maceration can be painful and athletes say it feel like a giant blister on the bottom of their feet.
In the Amazon Jungle Marathon, the trick will be to dry the feet at the end of each day’s stage. Because the feet will be wet during much of each day’s stage, the runners will have to find the balance between very dry and very wet, avoiding moist as much as possible.
Here’s some advice from my previous post about training with wet feet.
As said earlier, stop and deal with any hot spots as soon as you feel them. Check for folds in your socks, friction from dirt or sand, pressure inside your shoes – and get rid of these irritants. Lube the area or apply a piece of tape or blister prevention patch to help. This may seem like common sense, but many people ignore this simple step.
At the end of each day’s stage, remove your wet shoes and socks, dry your feet and air them as much as possible. If your feet have tape on them, remove the tape to dry the skin underneath. Wear sandals or Crocs around camp to keep your feet away from the wet ground and dirt and sand. Walking around barefoot will often aggravate wet, cold, and soft macerated skin. Later in the day or the next morning, re-tape your feet and patch any blisters.
Rest assured that I will write about how everyone’s feet held up in the wet Amazon jungle.
Credit is due to Rebecca Rushton for her Blister Prevention Report. Her website is Blister Prevention. Check out her website and sign up for her newsletter and free reports.
Here is the link to the Jungle Marathon Amazon.
If you want to read more, check out this article I did in November 2012 about Stuart Crispin who completed the race in Vibram FiveFingers.
Filed under: blister care, Foot Care, Foot Care Products, Footwear, Sports
In my last post, I talked about four ways to reduce shear and the likelihood of blisters. To recap, they were fit, cushioning, moisture management, and socks. Today’s post will cover a fifth way by using ENGO Blister Prevention Patches.
Tamarack Habilitation Technologies is well known for providing healthcare professionals and clients with innovative, value-added orthotic-prosthetic componentry and materials. Their ShearBan product is similar to the ENGO Blister Prevention Patches reviewed in this article. ShearBan is used in the orthopaedic and prosthetic industry on prostheses at amputation stump sites to reduce the incidence of skin breakdown.
Introduced in 2004, ENGO Blister Prevention Patches have radically redefined the way hot spots, blisters and calluses are treated. As a preventative measure, ENGO patches provide peace-of-mind that blisters won’t become a painful, debilitating problem. If a blister has already formed, applying patches to footwear, corresponding to the blistered area eliminates painful irritation and further skin damage, allowing continued activity. Friction forces are reduced by more than 50% when you apply an ENGO Patch to your footwear.
The patches are made from an ultra-thin Polytetrafluoroethylene (PTFE) film and are 0.015 inches total thickness – a very slippery surface. They are very durable, lasting four to six weeks in most applications. The aggressively sticky patch peels away from the backing and is applied to dry shoes or boots. The PTFE ENGO Patch reduces the ‘stickiness’ between the shoe and sock so they can glide over one another. The foot, inside the sock, glides over the patch shear distortion and friction are reduced, and blisters can be averted, in spite of pressure.
Avid runners, hikers and sports players rely on their feet to reach performance goals; from day hikes to ultra marathons. But quality footwear and socks alone don’t eliminate the skin trauma your feet can experience from repetitive rubbing — building friction forces to levels that cause hot spots, blisters and calluses. While I use these patches in runners’ footwear at races, they can also be used in ordinary every day shoes to reduce calluses.
Similar to Tamarack’s ShearBan material, ENGO patches are applied directly to footwear and equipment, not to the skin. Outcomes of this unique application include ease of use, long-lasting and guaranteed friction relief.
ENGO Patches are made in several sizes and types:
- A large oval – 2 ¾ x 1 ¾
- A small oval – 2 x 1 ½
- A rectangle – 3 ¾ x 2 ¾
- Back of the heel patch – 3 ¾ x 1 ¾
- A cushion heel wrap – 3 ¾ x 1 ½
When I work a race I always have a bag with different sizes of ENGO patches. I have applied the ovals and rectangles and the back of the heel patches. The patches are applied to the shoes and insoles – not to your skin. This means wherever you are going to apply a patch has to be dry. My advice is to apply patches before your race when your shoes are dry. I have used them inside the shoes in the sides, in the heels, and on the insoles.
Typical problem areas in footwear are under the heel and forefoot, and at the side of the heel. An oval patch can be applied to overlap the side of the heel counter and the insole as seen is the photo. I often use a rectangle or large oval under the ball of the foot or an oval under the heel – applied directly to the insole. The patches are useful over stitching or seams in footwear that are rubbing the wearer. If necessary, a patch can be cut to shape for where it will be applied.
The patches will reduce shear and friction; provide relief from hot spot and blister pain, and can be used in any type of insole or orthotic and footwear, from sandals to running shoes, and any type of hiking or ski boot.
I like ENGO patches because they work. The patch is thin and does not alter the fit of the shoe. When properly applied to dry footwear, they stick.
Rebecca Rushton, a podiatrist in Australia, strongly recommends ENGO Patches. She discovered the patches after getting blisters herself and now represents ENGO in Australia. She has written several free reports on blister prevention available on her website, Blister Prevention.
If you are unclear about shear and blister formation, here’s a link to my article An Introduction to Shear and Blister Formation.
The Technical Stuff
JM Carlson, in a 2009 report wrote, “The measurement of friction is the ‘coefficient of friction’. The coefficient of friction (COF) is a number that represents this slipperiness or stickiness between two surfaces and is generally below 1.0. Within the shoe, the COF between the foot, socks and insole can range from 0.5 – 0.9. In contrast the COF between a sock and a polished floor is around 0.2.” Tests have shown PTFE patches to reduce the coefficient of friction (COF) in the shoe by up to 80%. The COF is in approximately 0.16, which is significantly lower than all other in-shoe materials. Importantly, the low COF is maintained even in most and wet conditions inside the shoe.
Check out GoEngo.com for more information about ENGO Blister Prevention Patches. They also offer a money-back guarantee.
Disclaimers: I support ENGO Patches and am supplied with whatever I need for the events I work. I am an affiliate of Zombierunner and make a bit of any sale made through the link above.
Back on June 17 I introduced the concept of shear with a post by podiatrist Rebecca Rushton from Australia who has studied blisters and identified shear as a major factor in blisters.
It’s best to start by refreshing our memories about what was shared on the previous article. Here’s the link in case you want to see the full post: An Introduction to Shear and Blister Formation. Otherwise, here’s a short piece from that post:
Poor blister prevention outcomes are due in no small part to the misunderstanding of the cause of this obstinate injury. The force that causes ‘friction’ blisters is not friction. And it’s not rubbing. It’s shear. But if you ask 100 people the question “what causes blisters”, nobody would answer “shear”. Shear is the sliding of layers across one another – internal layers that are structurally connected. Those connections can break and when fluid fills that cavity, you have a blister! What Does Shear Look Like? Try this … Step 1: Place the tip of your right index finger on the back of your left hand. Step 2: Wobble it back and forth but keep it stuck to the same bit of skin. Notice how your skin stretches? This is shear and this is what causes blisters. Shear might look like rubbing but it’s not. Notice how your finger tip has not moved relative to the skin of the back of your hand? But your hand skin has moved relative to the underlying bone. This is shear. Your skin doesn’t need anything to rub over it for blisters to form. It just needs shear (this stretching of the internal tissue layers) to be excessive and repetitive.
Managing shear is key to managing blisters. Let’s look at several ways to reduce shear.
The first way is to make sure your footwear fits. Many people buy shoes that seem comfortable in the store but don’t make sure they feel ok by wearing them around the house for a few days. Make sure they have enough room in the toe box both in height and length. Make sure there is not undue pressure on soft tissues over any bony spots (sides of the forefoot, ball of the foot, sides and back of the heel, over the instep, etc.). Make sure they are not too loose, allowing too much movement leading to skin abrasions, hot spots, and then blisters.
Using a cushioning product is a second way to reduce shear. This might be a gel pad under the ball of the foot or under the heel bone, or a replacement insole meant to pad and cushion.
A third method is to manage skin moisture. This can include skin-drying strategies and skin lubrication. Studies have shown that you can reduce the incidence of blisters by keeping the skin either very dry or very wet. Drying the skin can be done with powder, benzoin, alcohol wipes, and antiperspirants. Lubricants can include SportSlick, BodyGlide, BlisterShield, and other popular products. Zinc oxide is also effective at controlling moisture. The method of having runners train with wet feet has been successfully used by Shirley Thompson and Vicky Kypta of the Jungle Marathon Amazon. They have found that the feet of their race participants have been better with this suggestion given to runners before the race.
The fourth method of controlling shear is with socks. This may include double layer socks or wearing two pairs of socks – a thin liner and usually, a thicker second sock. This allows movement between the two sock layers. Injinji toe socks are great for those with toe blister problems.
Next time, we’ll talk about a fifth way to reduce shear – Engo Blister Prevention Patches.
In the mean time, check out ZombieRunner for many products that can help with cushioning, skin-drying and lubricants, and socks.
This weekend close to 400 runners will start at Squaw Valley and make the trek over the Sierras towards Auburn – 100 miles away. It’s the Western States 100 Mile Endurance Race. I love the race, having completed it three times in the late 80’s. It’s tough and throws a lot at the runners. Cold, heat, extreme heat, streams running down the trail, rocks, dust and grit, water crossings, long ups and long down through numerous canyons – and for many runners, a second sunrise with renewed heat.
I will again be working at the Michigan Bluff aid station doing foot care. Later, I will be at the finish line taking care of feet as people finish. Having worked this race for years, I have a good idea of what foot problems to expect. Here’s what I commonly see and a few tips.
First, here are common problems:
- Toe blisters. Under the toenail, on the tips of toes, between toes, and under toes.
- Heel blisters. Either at the rear of the heel or at the sides.
- Ball of the foot blisters. Either in a certain area or across the whole foot.
- Side of the foot blisters.
- Stubbed toes. From hitting rocks or roots.
- Sprained ankles.
- Sore feet.
Here are some tips:
- Cut toenails short and them file them smooth. No rough edges to catch on socks or hit the toebox of your shoes.
- Reduce your calluses as much as possible. This close to the race, don’t file too much off. Aim to get reduce the thickest rough patches.
- Use Engo Blister Prevention Patches in problem areas – sides of the heels and ball of the foot. They will greatly reduce friction and shear.
- Pretape any problem areas.
- Check your insoles for thick edges at the sides of the heel – always a problem area. Thin these down or change insoles. Most side of the heel blisters are caused by these edges.
- Don’t use Vaseline as a lubricant. Stick to SportSlick, BodyGlide, or a similar lube.
- Change socks frequently and clean your feet. Today’s trails shoes often have mesh uppers, which allow sand, dirt, and trail dust inside the shoe, on and into your socks, and on your feet.
- Know how to manage your feet and patch blisters on your own – or your crew should have these skills. You can’t count on aid station people knowing what you need or want or doing it on your time schedule. There may be other runners in front of you or they may be out of supplies.
- If you feel something inside your shoe, stop and clean it out. Even a small rock can cause problems.
- Wear gaiters to keep rocks and trail grit and dust out of the top of your shoes.
- Build your own quality foot care kit. Stock it with what you need and learn to use everything.
Maybe I’ll see you at Michigan Bluff. I hope it’s just to say Hi as you run through.
Have a great race.
This is a guest post by podiatrist Rebecca Rushton from Australia. She has looked at blisters, how they are formed, what causes them, and how to prevent them. For years, the common thinking about blister causes has been friction, heat, and moisture. Rebecca’s research has led her to identify shear as a leading cause of blisters. Read the article and then check out her website. Over the next months, Rebecca and I will take an in-depth look into blisters, their formation, and treatments. Her website Blister Prevention has a lot of valuable information on blisters (more on that at the end of this post). Here’s Rebecca’s article.
An Introduction to Shear and Blister Formation
Foot blisters continue to wreak havoc with endurance athletes’ feet in spite of their best preventative efforts.
Poor blister prevention outcomes are due in no small part to the misunderstanding of the cause of this obstinate injury.
The force that causes ‘friction’ blisters is not friction. And it’s not rubbing. It’s shear. But if you ask 100 people the question “what causes blisters”, nobody would answer “shear”.
Shear is the sliding of layers across one another – internal layers that are structurally connected. Those connections can break and when fluid fills that cavity, you have a blister!
What Does Shear Look Like? Try this …
Step 1: Place the tip of your right index finger on the back of your left hand.
Step 2: Wobble it back and forth but keep it stuck to the same bit of skin. Notice how your skin stretches? This is shear and this is what causes blisters.
Shear might look like rubbing but it’s not. Notice how your finger tip has not moved relative to the skin of the back of your hand? But your hand skin has moved relative to the underlying bone. This is shear. Your skin doesn’t need anything to rub over it for blisters to form. It just needs shear (this stretching of the internal tissue layers) to be excessive and repetitive.
Rubbing Causes Abrasions
Most of us use the term rubbing to mean two surfaces moving across one another – like when you rub your hands together. The type of skin injury that rubbing causes is abrasions. An abrasion is where the top layers of skin are rubbed off – you end up with a red raw sore. Blisters (from shear) and abrasions (from rubbing) are completely different entities – they have different mechanisms of injury and affect different layers of the skin. Here’s a video on blisters versus abrasions on the feet.
Is the distinction important? Yes it is. The lack of understanding of blister causation is at the heart of why foot blisters continue to plague athletes.
Achieving True Blister Prevention Success
There are 3 factors that influence shear. Impacting on these is how we can minimise shear and prevent blisters.
1) Type of skin
Thinner and more mobile skin (like we saw earlier on the back of the hand) will abrade before it blisters. In contrast, thicker and less mobile skin (like on the palm of your hand) is the type of skin more likely to form and maintain a blister. Do the same experiment we did before but with your index finger on your palm – the skin is noticeably thicker and less mobile in comparison. (This is why blisters are most common on the soles and palms)!
Apart from the thickness and mobility characteristics which determine the ability to blister (and which you can’t do an awful lot about), shear is influenced by two other factors: friction and bone movement. You need both, not just one, to create skin shear. The good news is that these things we really can change! Change one or more of these, in one of many ways, and you can successfully prevent foot blisters.
Friction is the force that resists the movement of one surface against another. It’s the degree of slip or grip between surfaces. Low friction (slippery) is when two surfaces glide easily against each other. High friction (sticky) is when the two surfaces tend to grip together.
The moist in-shoe environment during exercise causes high friction levels between the shoe, sock and skin. This causes these materials to stick together … yes the shoe sticks to the sock and the sock sticks to the skin … for longer. They all stick together for longer because of high friction.
3) Bone Movement
Meanwhile, as we run the bones move back and forth. With the skin remaining stationary (for longer) and the bones moving back and forth as far as they can go, the soft tissue in between stretches – that’s what shear is.
This concept of friction and bone movement leading to shear is depicted in the diagram below and in this video demonstrating shear.
The purple area is a section soft tissue between the skin surface and its underlying bone. Although the heel itself has not lifted within the shoe due to high friction levels, the bone has moved up relative to the skin surface causing shear to the soft tissues in between.
Rebecca’s website Blister Prevention has a lot of valuable tips and techniques, and information on blisters. Take some time and explore the site, subscribe to updates and receive a copy of her ebook, Blister Prevention for Active People. Rebecca is a podiatrist in Australia.
Next Up? More on Shear and Blister Treatments
Over the next month or two, we will talk more about shear and common blister treatments – including what works and doesn’t work. Make sure you are a subscriber to this blog to receive each post. You can do that at the box at the upper right side of this page.