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The No-Slip Winter Shoe This work has been published in the Teen Ink monthly print magazine.

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   As with any winter season, snow and ice are major concerns for people. Children and adults find it difficult to walk on hazardous, icy sidewalks. Many accidents occur when people do not shovel. As the temperature drops below freezing, the snow becomes a glassy sheet of ice that is extremely slippery. Gusty winds can cause us to fall or slip. The memories from the winter of 1993-94 in the northeastern United States, nicknamed "The Storm of the Century," consisted of nearly 15 subsequent snowstorms. These visions are still fresh in our minds.

With these problems in mind, we have developed a new type of shoe designed to help people in the NYNEX area walk around more easily without sliding on icy sidewalks and streets. Our new shoe is based on the boots used for ice-climbers but is adapted for the use of common pedestrians. The shoe will be easy to put on and will be comfortable to wear.

The sport of ice-climbing comes from the sixteenth century. Alpine shepherds attached spiked horseshoe devices to the sole of their feet. This allowed them to counteract the slipperiness of the ice on steep slopes. They also carried iron-tipped sticks to help them walk. In the early 1800's, tourists from England began vacationing in the alpine villages. Their curiosity was piqued by the spectacle of inaccessible mountain tops. They hired peasants to guide them among the peaks. This sudden interest in ice-climbing led to many improvements in equipment and knowledge of ice conditions. The shepherd's three-pronged "crampon" was replaced by nailed boots; the "alpine sticks" were shortened to accommodate man's height; and the adze was added for chopping steps to climb steep slopes of ice. The latter half of the nineteenth century - the Golden Age of mountaineering - saw all the summits of the Alps climbed. Alpine guides traveled as far as Argentina, Russia, New Zealand and Canada to establish their sport in these places. It was not until the sport became popular in the United States, that new standards of ice-climbing were set.

Mike Weiss and Jeff Lowe, professional ice-climbers, discovered that chromemolly tubes with tips beveled to the inside could be driven in the ice without destroying it. On January 2, 1974 they found their homemade invention very useful when climbing near-vertical ice at the Colorado Bridalveil Falls. Within the last twenty years, reverse-curve and interchangeable picks with graphite shales evolved from simple angled picks and sticks. Footfang crampons and Snarg ice pitons made their first appearance. Interested participants in this popular sport increased worldwide.

For years, ice-climbers used a special technique called "smearing," while walking on icy surfaces. The idea was that the entire sole is placed firmly on the ice and pressure by the weight of the body is placed on the shoe. We are able to walk or run only because of the frictional force at the ground acting on the foot in the direction in which we want to move. The importance of the frictional force developed between the shoe and the ground during walking, especially at heel strike and toe-off Force plate studies indicate that the horizontal component of foot force at heel strike is about 15 percent of body weight, and at toe-off, 20 percent of body weight. This increase in normal force helps to provide adequate stabilization for the foot. The rubber and plastic in the sole would provide the friction necessary so the climber would not fall. This technique will reduce the chance of people falling and hurting themselves.

Walking with equal pressure on the foot forces the hamstings and gluteus muscles to be active. There must be a large movement about the hip and muscles in front of the hip. Between these stages the body moves forward horizontally so the knee must be bent. That is likely to result in large movements at the knee joint, requiring the quadriceps muscles to be active. Muscle tension costs metabolic energy, so we would burn a lot of fuel walking like this. Normally we do not walk with pressures on all areas of the foot. While each foot is on the ground we keep its knee almost straight. The body is higher when supported by a straight vertical leg than when supported by straight sloping legs, so we rise and fall. The up and down movement of our body implies that the force on the ground is not always equal to body weight. By using a pedobarograph we can see the distribution of pressure on bare feet. The two areas of greatest pressure are found in the heel and the metatarsupahalangeal joints of the foot.

Walking requires adequate friction between the sole of the foot and the floor, so that the foot will not slip. In dealing with pressure distribution beneath the foot, speed increases the pressures on the foot and shift medially. The toes contribute more by assuming more loading as the walking speed increases.

Although many materials have been used to improve the ice-climber's boot, the same technology should be available to help improve the pedestrian's shoe. It should help the pedestrian walk around safely in icy and snowy conditions. There is a wide array of snow shoes and boots around for the winter season, but none of them is designed in a way to combat the main problem - falling on slippery ice. Jeff Lowe described the perfect snow shoe as: "a very stiff but not rigid sole; a rigid roomy toe that will stand up to step-kicking in hard snow; a flexible ankle that allows full range of motion with little resistance or irritation at the boot top; light weight; with the inside with crash resistant neoprene foam; and a fit that holds the heel firmly in place." These are the ideal characteristics of a shoe to help a person walk better and have more control and flexibility. These qualifications of a perfect snow shoe are our main objectives for reinventing the "perfect winter shoe."

Based upon our research and correspondence with several mountain climbing manufacturing companies, we have concluded that the best materials to make the overshoe would be a foam called Duratherm, a warm polyester insulation. It will provide warmth and avoid the "clunky and heavy" look of ski boots. The insulation will not compress together with time so the mold of the shoe will not change. This is important in improving the longevity of the shoes. We tried to find a special material used for shoes to provide a waterproof surrounding, yet would also allow the feet to perspire freely.

The answer was in the Lowa plastic shoes, made in Germany. Mark Guider, a representative of Climb High, the American distributor, informed us that Gore-Tex is the unique material used in their shoes. Gore-Tex is waterproof and windproof that allows your feet to breathe comfortably. The Gore-Tex material is laminated to another fabric, usually a lightweight knit tricot. This material is very important in the Lowa shoe and should be incorporated into our new design because it will retain heat generated by the foot, while allowing the perspiration vapor to escape.

We plan to use Gore-Tex material with knit tricot to insulate the inside of our shoe. It would provide warmth for the feet and minimize the chance of getting frostbite. The sole will be a correct mix of rubber and plastic to produce the "smearing effect." Also on the sole of the shoe will be metal prongs that will protrude slightly. The prongs are similar to the crampons that are commonly used by ice-climbers. The metal prongs reduce vibration and provide a strong balance on ice. In effect, they provide resistance on glass sheets of ice. The metal prongs are placed in the areas of highest distribution of pressure in front of the heel and in the ball of the foot. Two metal prongs are placed near the front of the foot and two are placed near the heel.

As you can see in our diagram [illustration 1], we made the soles of the shoe slightly thicker than regular walking shoes. The reason is that the shoe will be slightly above the snow areas and it will be easier to walk. For added convenience, we made the shoes with a plastic covering and Velcro straps to tighten the shoe. This would make the shoe easier to dry and clean, and faster to put on. We also designed the shoe stylishly so children, teenagers, and adults would be apt to wear them. Our second design for our shoe would be exactly the same except that it would be worn over regular sneakers or flat-shoes. This design would provide convenience to the family. The shoe would be wider and be able to expand more. This would allow a person to wear regular shoes under our overshoe.

On a frictionless surface (for example on ice), a regular sneaker would easily allow a person to slip. With our new shoe, the metal prongs would create friction between the ice and the shoe. But this is where we run into a problem: the metal prongs do not work well on other surfaces, like tile floors. They become extremely unstable on concrete and with their pointy ends, they scratch floors and erode surfaces. So the idea of metal prongs would have to be reconsidered. But we had to keep in mind that on ice, metal prongs work best. They suited our purpose.

The logical approach would be to change the metal prongs to rubber prongs. Rubber tips are found on the bottom of canes to create friction on concrete. But, we did not have proof that rubber would create enough friction on ice to counteract sliding. We came up with an idea that pieces of melted rubber material could be placed on the tips of the metal cramnons. They would be safe enough to be worn on regular floors because the metal points would not be exposed. It would also work very well on ice because the pressure points from the foot would place the same amount of pressure to create friction. We believe this idea will incorporate our main purpose of this project - comfort and reliability on ice. The metal crampons would still remain stable on the ice and create friction. The rubber tips would prevent the damage and prevent a person from slipping on floors.

Our snow shoe, no matter how sophisticated or technologically advanced, may or may not be accepted in the general consumer market. The prongs on the bottom of the shoe are made for people who are heel or toe walkers. But cautious people might walk differently and provide equal force on all parts of the sole. This might counteract the effectiveness of the prongs.

The shoe should not be worn in place of ice-skates in a skating rink or on a frozen pond. It is designed specifically for streets that are covered with some ice, snow and slush. It is only a snowshoe and cannot be misused for any other purpose. The shoe cannot guarantee absolute protection from falling but would minimize your chances of falling.

We also think that the general public should be educated about the dangers of ice. We think that this shoe is a good starting point for teaching people. There are many devices available to the public and our winter shoe is one of them. Once people are better educated about walking safely on ice, they would know what they can do to prevent themselves from slipping. Once the public is more aware of the solutions available, they would be better protected.

Based upon the current market rates, the average ice-climbing boot with a GoreTex lining costs around $400. The separate crampons can cost up to $40. We estimate the cost of our walking shoe to be less than half of the professional's shoe. The reason for this is that our shoe is basically the same as any shoe but with protection, the plastic prongs, and the Gore-Tex lining for warmth. We also added more foam to the shoe to maintain its stiffness. The only expensive materials are the Gore-Tex and the Duratherm foam. But with increased demand and the common application for Gore-Tex, we are sure the price of these materials would decrease.

Our proposed solution, the new winter shoe, is both convenient and practical. No other shoe technology is specifically made for easy walking use in icy and snowy conditions. We converted the technical shoe into a shoe that would be widely appreciated and practical for family use. If the problem of walking in icy conditions is not addressed properly, many minor and major accidents will occur. We need to have shoes that help us walk around in most winter conditions. The shoe we are proposing is safe to wear if used properly. With all the accidents occurring in the city and all the lawsuits being filed, a shoe that would help people balance themselves better is long overdue. u


This work has been published in the Teen Ink monthly print magazine. This piece has been published in Teen Ink’s monthly print magazine.






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