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From Fellrnr.com, Running tips
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[[File:Fixing Blisters Small.jpg|right|thumb|200px|I worked the aid station at Umstead 100, fixing runners' feet, which is given me a wide experience with the types of blisters ultrarunners suffer from.]]Runners should not get blisters except for the most extreme situations. I suffer from a skin condition called [[Epidermolysis Bullosa]] that makes my skin blister easily, but I can run 100+ miles without blisters. There * Good [[Running Form]] is important for blister prevention. If your foot scrapes as it lands then the shearing forces can cause blisters.* Shoes have to fit correctly, which is surprisingly tricky. Most running shoes are a number of approaches not designed to preventing fit the human foot, and have two boxes that squash the toes in. I frequently see blistersin ultrarunners wearing [[Hoka Shoe Review| Hoka shoes]], but the keys other conventionally shaped shoes are good also problematic. I'd recommend [[Running FormShoe Modifications| cutting open the toe box]] as this prevents a lot of toe blister problems. Alternatively, focus on Altra and correctly Topo shoes, or look for other shoes like the [[Merrell Trail Glove]] that are shaped for the human foot.* While socks can't prevent blisters from badly fitting shoes, you can get blisters wearing could shoes and poor quality socks.* Hydration and electrolyte intake can be a factor, as these can cause your feet to shrink or swell.* Calluses are a potential warning sign, and it's common to see blisters form under calluses. While it's worthwhile keeping calluses file down and moisturized, it's far more important to fix the underlying cause.* Toe nail care is critical; keep them short and equally important, smooth the edge so it's rounded and won't catch on the inside of your shoes. ==Causes of blisters==Blisters are primarily caused by shearing force, which is where force is applied to the skin across its surface. Blisters can also be formed due to trauma, such as stubbing your foot, or being squashed by ill-fitting shoes. [[File:Sheering-Force.gif|frame|nonecenter|Sheering force causing a blister]]===Exacerbating factors – Heat & Moisture===
Neither heat nor moisture will cause blisters, but they will make them more likely as they both tend to weaken the structure of the skin. If the skin is wet for long enough it will macerate, which sometimes called 'prune skin'. Macerated skin tends to wrinkle up, become white, quite soft and is far more likely to blister.
There are several key steps to preventing blisters.
Bad [[Running Form]] will not only make you slow and cause injury, but it is also a leading cause of blisters. With a good [[Cadence]] and [[Running Form]], your feet will land gently and quietly on the ground, producing little shearing force or impact. A slow [[Cadence]] or a poor [[Running Form]] will produce a sharp shearing force that will tear at the skin, causing blisters over time. Running downhill can make the shearing forces far worse, and a poor [[Downhill Running]] style is likely to cause serious blisters. When running downhill, your foot should land softly and the braking force should be even for the time the foot is in contact.
{| class="wikitable" style="margin-left: auto; margin-right: auto; border: none;"
|- valign="top"
|[[File:Foot-Landing-Badly-small.gif|frame|none|x150|Without paw-back, the foot is still moving forward at the time of contact, creating shearing force]]|[[File:Foot-landing-correctly-small.gif|frame|none|x150|Correct paw-back brings the foot backward in relation to the body, so that it touches down without any forward motion.]]
|}
A badly fitting shoe can cause blisters even with good [[Cadence]] and [[Running Form]]. When buying [[Shoes]], try them on when your feet are warm, preferably at the end of the day, and with the socks you will run in. You should generally choose your socks, and then buy your [[Shoes]] to fit with those socks. Some socks are available in a variety of thicknesses, so you can tweak the fit with different socks.
Your foot will slide around in a loose shoe and the pressure will tend to be in small areas, focusing the friction and shearing forces in hot spots. One test of shoe fit is to put your [[Shoes]] on, but leave the laces completely loose and see if you can walk around without your heel coming out. A good fit will have the shoe fitting gently against your foot, but without any area of higher pressure or pinching.
Remember that losing or gaining body fat can change the size of your feet. [[Shoes]] that used to fit you perfectly may not longer fit the same. A more acute problem occurs on longer races when the feet swell up. Having spare [[Shoes]] that are slightly larger, or thinner socks for later in a race can help with this problem. Of course, getting the fit right is hard, as you can't practice this until your feet are swollen, and different situations may produce differing levels of swelling.
The arch is a naturally strong structure, but arches are damaged by forces pushing up under their middles. This is particularly true of the arches of your feet; they are strongest when there is nothing pushing up under the arch. However, if you've worn [[Shoes]] that push up under the arch for some time, this will weaken the arch. This is similar to having a limb in a cast; the cast supports the limb, but the limb weakens quickly. Therefore when you try to move to a shoe without arch support, it can be like taking a cast off a limb. Your foot will take time to strengthen and recover from using arch support. The other downside to arch support is the pressure can easily cause blisters. This is especially true of orthotics.
It is possible for the edge of the insole to cause a blister, though this is fairly rare unless the insole moves within the shoe.
A bad seam or excess glue can cause a sharp edge that could tear up your skin. A shoe can fit correctly, but cause blisters due to manufacturing problems such as a bad seam. A shoe that bends in the wrong place can have a crease that causes a blister as well. Also, check that your insoles do not slip. Some double sided sticky tape between the shoe and the insole can prevent this.
Dehydration can be a contributor to blisters, as the skin loses some of its tension ([http://www.nlm.nih.gov/medlineplus/ency/imagepages/17223.htm skin turgor]) with significant dehydration. However, reduction in skin turgor is generally associated with 6-9% dehydration (excluding [[Glycogen]] depletion water losses), at which point the dehydration itself should be more of a problem than the blisters. [[Hyponatremia]] is a dangerous condition and one of the symptoms is swelling of the hands and feet, which can cause black toenails or blisters. Read up on [[Practical Hydration]] and [[The Science Of Hydration]].
[http://en.wikipedia.org/wiki/Callus Calluses] are a sign of poor fitting [[Shoes]]. A callus is a spot that is likely to turn into a blister with longer distances. You can file down a callus and keep is moisturized, but that is a symptomatic approach. The key is to fix the underlying problem, which is normally the fit of your [[Shoes]]. Note that a callus is a spot that is thickening; the general thickening of the skin due to being barefoot does not tend to cause this problem. The key is to watch out for small areas or spots that have excessively thick skin.
A lubricant will reduce the friction between your skin and your socks, which can help reduce the shearing forces, and thus the blisters in some situations. However, most lubricants will also keep your feet warmer and by keeping your sweat against your skin, make the skin wetter. This added heat and moisture will soften the skin and make the chance of blisters greater overall. In [[Running in the Cold|cold conditions]], smothering your feet in Vaseline can work well, as the added warmth is actually an advantage. Also remember that lubricating your feet can cause a problem if you do get blisters and want to tape them, as the lubricant makes it harder for the tape to stick. Wiping your feet with paper towels, then with paper towels soaked in rubbing alcohol can remove most of the lubricant, but that process takes time to do properly.
Here is a partial list of some of the options
* Hydropel helps prevent the skin absorbing moisture and is particularly useful in wet conditions. It does lubricate slightly, but its water repelling powers are its prime attraction.
* SportsShield is similar to Hydropel, both being based on a silicone lubricant (dimethicone). SportsShield is available as a roll on and towelette, whereas Hydropel is dispensed from a toothpaste like tube. SportsShield goes on much easier than Hydropel and results in less friction, but less water repelling as well. * Vaseline is cheap and can be used in large quantities. This can provide good lubrication, but tends to keep the skin quite moist. It also makes it harder to attach tape if this is required later. * Aquaphor is quite similar to Vaseline. Though it has different ingredients, I have not found a significant practical difference as a foot lubricant. * Bodyglide is one of the original products purposefully marketed as a sports lubricant. While effective, it does not seem to last very well, nor does it reduce the friction as much as other products. ===Powders===
Like lubricants, powders can reduce the friction between your feet and your socks. While powders do not keep your feet warmer or wetter in the way lubricants do, the powder does tend to clump up when damp. These clumps of powder can then lead to blisters.
Here is a partial list of some of the options
* Blister Shield powder is Teflon, which I found helps a bit, but tends to form clumps when wet. * Zeasorb powder absorbs six times its weight in water, which sounds effective, but water is heavy and powder is light. To absorb the level of sweat put out by a runner, a lot of powder is required, which I've found to be impractical.
See [http://www.zombierunner.com/store/categories/foot_care/powders/ Powders] and [http://www.zombierunner.com/store/categories/foot_care/lubricants/ Lubricants].
Like the other desperate measures, [[Taping]] can reduce the friction between your sock and your feet. Unlike lubricants and powders, [[Taping]] can help absorb some of the shearing force, though this depends on the particular tape used. A flexible tape will just transmit the shearing force to your skin, but an inflexible tape can absorb and spread the shearing force. There are several downsides to [[Taping]]
* [[Taping]] will keep your skin warmer and wetter. This depends on the tape, but thicker tapes and tapes that are waterproof are worse. Duct tape is especially bad and will cause the underlying skin to become saturated as it holds the sweat against the skin. * The tape can crease, causing ridges that create extra pressure and blisters. Again, duct tape is particularly bad for this. * If the tape works loose, it can bunch up and cause a blister. Occasionally the tape can migrate around your foot and cause a blister in an unexpected and unpleasant new area. * Should you get a blister under the tape, it can be quite painful to remove the tape to determine the extent of the problem. (I’ve I've seen a number of cases where are runner was convinced they had a blister, but the skin was fine.)
For more details see [[Taping]].
This section is intended to provide specific guidance for blisters in specific places on your feet. I've ordered the sections based on how frequently I've seen the problem.
Blisters on the tips of the toes sometimes start with a blister under the toe nail that spreads out, and sometimes it starts on the tip and spreads under the toe nail. If you suspect the blisters are starting with the toe nail, see the next section.
Suggested fixes (in order of preference)
* Have someone check your [[Running Form]] to make sure your feet are landing softly with the correct paw-back. Listen to the sound your feet make when they land for a scraping sound as well as the sensation of your foot pushing forward in your shoe at the point of landing. This is a sign that you are not pawing-back. * If the problem is occurring on hilly courses, make sure your [[Downhill Running]] form is right. Your foot should land and be in firm contact before your foot starts to act as a brake. * Check your [[Shoes]] are tied correctly and that the pressure on your feet to slide forward is taken by the area under the laces rather than allowing your feet to slide forward and your toes to hit the end. * Check your [[Shoes]] are not creasing at the toe box and pressing against the tips of your toes.
* Buy [[Shoes]] with a longer toe box so that your toes do not reach the end.
* Cut open the toe box so that your toes do not reach the end.
* Wear Injinji socks (unlikely to help, but worth a try).
* [[Taping| Tape]] the ends of your toes. If you are not also wearing Injinji socks, it is best to tape all of your toes so that tape does not rub on the next toe. ===Blisters under or behind toe nails===
I don't have any toe nails due to my [[Epidermolysis Bullosa|skin condition]], so this is not practical experience. This type of blister sometimes manifests itself as a blue or black toenail; the toenail has not changed color, it the blister under the toenail that you can see.
Suggested fixes (in order of preference)
* Trim your toes nails so they are short. I'm told that a pedicure before a big race is a good idea.
* File down the edge of your toe nails so that the edge is rounded rather than flat. * Have someone check your [[Running Form]] to make sure your feet are landing softly with the correct paw-back. Listen to the sound your feet make when they land for a scraping sound as well as the sensation of your foot pushing forward in your shoe at the point of landing. This is a sign that you are not pawing-back. * If the problem is occurring on hilly courses, make sure your [[Downhill Running]] form is right. Your foot should land and be in firm contact before your foot starts to act as a brake. * Check your [[Shoes]] are tied correctly and that on downhill sections any pressure on your feet to slide forward it taken by the area under the laces rather than allowing your feet to slide forward and your toes to hit the end.
* Buy [[Shoes]] with a longer toe box so that your toes do not reach the end.
* Cut open the toe box so that your toes do not reach the end. * Wear Injinji socks.
* [[Taping| Tape]] your toes over the nails. If you are not also wearing Injinji socks, it is best to tape all of your toes so that tape does not rub on the next toe.
This section is about blisters on the sides of the forefoot, but above the line of the insole. If you have getting blisters along the insole line, see the section below. Suggested fixes (in order of preference)
* Check your [[Shoes]] are the right size; a loose shoe can rub on the sides of your feet. Also, a shoe that is tight in the forefoot but loose elsewhere can cause excess pressure. * If the problem is occurring on hilly courses, make sure your [[Downhill Running]] form is right. Your foot should land and be in firm contact before your foot starts to act as a brake. * Check your [[Shoes]] are tied correctly and that on downhill sections any pressure on your feet to slide forward is taken by the area under the laces rather than allowing your feet to slide forward and cause the sides of the forefoot to rub.
* Watch where you're placing your feet on trails. If you land with the edge of your foot on a rock, your foot can twist in your shoe, putting a huge shearing force on the skin at the sides of your feet.
* Consider modifying your [[Shoes]] to cut open the area that rubs.
This section is about blisters on the sides or back of the heel, but above the line of the insole. If you have getting blisters along the insole line, see the section below. Suggested fixes (in order of preference)
* Check your [[Shoes]] are the right size; a loose shoe can rub on the back of your heel.
* Get socks that are long enough to prevent the top of the shoe rubbing on the skin. The short, 'no see' style socks can cause problems.
* Make sure your [[Shoes]] are not inflexible. As your foot bends when you run, an inflexible shoe will try to slide down your heel, causing blisters.
This is a particular problem with [[Hoka Shoe Review| Hoka Shoes]] due to their tight toe box, but it happens with other shoe types as well. If the blister is at the base of the toe where it meets the forefoot then it's likely that the blister started under the forefoot. Suggested fixes (in order of preference):
* Buy [[Shoes]] with a wider toe box so that your toes are not pushed together.
* Cut open the toe box so that your toes are not pushed together. * Wear Injinji socks.
* Use a small amount of lubricant between your toes.
* [[Taping| Tape]] the toes to prevent them rubbing together.
This is probably the worst place for blisters, as it is the key load bearing part of your foot. If the blister spreads to where your toes join together, it is possible to [[Taping| tape]] this area, but it's tricky. Suggested fixes (in order of preference)
* Have someone check your [[Running Form]] to make sure your feet are landing softly with the correct paw-back. Listen to the sound your feet make when they land for a scraping sound as well as the sensation of your foot pushing forward in your shoe at the point of landing. This is a sign that you are not pawing-back. * If the problem is occurring on hilly courses, make sure your [[Downhill Running]] form is right. Your foot should land and be in firm contact before your foot starts to act as a brake. ==Blisters under the front of the forefoot==This is probably the worst place for blisters, as it is the key load bearing part of your foot. If the blister spreads to where your toes join together, it is possible to [[Taping| tape]] this area, but it's tricky. Suggested fixes (in order of preference)* Have someone check your [[Running Form]] to make sure your feet are landing softly with the correct paw-back. Listen to the sound your feet make when they land for a scraping sound as well as the sensation of your foot pushing forward in your shoe at the point of landing. This is a sign that you are not pawing-back.* If the problem is occurring on hilly courses, make sure your [[Downhill Running]] form is right. Your foot should land and be in firm contact before your foot starts to act as a brake.{| class="wikitable" style="margin-left: auto; margin-right: auto; border: none;"|- valign="top"|[[File:Forefoot blistersA (2).jpg|none|thumb|x200px| This is a surprisingly commonplace for blisters, and tricky to tape.]]|[[File:Forefoot blistersA (1).jpg|none|thumb|x200px| I use a butterfly shaped piece of tape to cover the blister.]]|[[File:Forefoot blistersA (3).jpg|none|thumb|x200px| The top side of the butterfly anchors the tape.]]|}==Blisters under the heel of the foot===
Suggested fixes (in order of preference)
* Have someone check your [[Running Form]] to make sure you are not heel striking. * If the problem is occurring on hilly courses, make sure your [[Downhill Running]] form is right. You are more likely to [[Foot Strike| heel strike]] on a steep downhill than on the flat. ===Blisters along the edge of the insole===
Suggested fixes (in order of preference)
* If the insole is loose, some double sided tape will hold it in place. * If the edge of the insole is rough, try carefully rounding the edges by trimming with scissors.
* Try replacing the insole with an aftermarket alternative.
* Change shoe type. ===Blisters under the arch===
This is an unusual place to have blisters. Suggested fixes (in order of preference)
* Change to [[Shoes]] without arch support.
* If you have orthotics, talk to your supplier about the blister problem.
* If all else fails, pre-tape the area.
See [[Toughening Feet]]
