A Survey About Feet From The 2012 Amazon Jungle Marathon

Vicky Kypta is the Medical Team Manager for the Jungle Marathon, which starts October 6 in the Amazon in Brazil. Last year she did an informal survey of the participants and the results are interesting. The race lasts seven days and goes through the jungle on pre-existing paths, trails, and tracks with natural obstacles to pass including streams and shallow rivers. This leads to feet that are constantly wet.

Jungle Marathon foot care

Jungle Marathon foot care

This is the race that I will be at in a few days.

Vicky shared the results of the questionnaire and commented it was quite interesting, although the sample group was quite small. There were about 30 participants.

Here are some of the findings:

  • 77% of the respondents wore Injinji socks
  • 100% of those NOT wearing Injinji sock got blisters
  • 46% of those wearing Injinji sock got blisters: out of those 50% were on the balls of the foot and 50% were on the toes. Those who had blisters on their toes all wore shoes in their normal size.

Out of those with no blisters:

  • 100% wore Injinji socks
  • 100% wore shoes one size larger
  • 75% applied some form of anti-friction compound to their feet; i.e. Body Glide, 2nd Skin or Zinc Oxide cream
  • 75% pre-taped problem areas or hotspots

I find this interesting and wonder what we will find with the 78 participants next week. The Jungle Marathons are well run and the staff tells runners to train with wet feet. They have found this results in less foot problems.

The results are striking in several areas (remember this is a seven day stage race):

  1. All the runners who did not get blisters wore Injinji socks and shoes a full size larger than their normal shoes
  2. All the runners who did not wear Injinji socks got blisters
  3. Runners wearing their normal size shoes all got toe blisters
  4. The majority of blisters were on the forefoot and toes

Over the past 17 years, I have worked a lot of ultramarathons and multi-day stage races. I can honestly say that overall, feet have improved. More runners are prepared and know how to manage their feet.

When I return, I will share what we found at this year’s Amazon Jungle Marathon.

Moisture on Your Feet – Moist, Very Wet or Very Dry

September 22, 2013 by · 1 Comment
Filed under: blister care, Foot Care, Health, Sports, Travel 

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

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.

Amazon Wet Foot

Amazon Wet Foot

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.

ENGO Blister Prevention Patches

September 8, 2013 by · Leave a Comment
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.

ENGO in Footwear

ENGO in Footwear

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.

ENGO Applied

ENGO Applied

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 Patch in Shoe

ENGO Patch in Shoe

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.

ENGO in a Shoe's Heel

ENGO in a Shoe’s Heel

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.

ENGO Patches can be purchased at the ENGO website, Zombierunner.com, and Rebecca’s Blister Prevention website.

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.

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