We find ourselves in the midst of Olympic games fever once again. Our top athletes are competing at the highest level and strive for top honours in their chosen fields.
Before we investigate the type
of footwear used by our athletes let's examine a modern football boot.
If we look carefully we can see that it is made from a variety of materials
chosen because of their individual properties.
|
Material
|
Why
used
|
| Kevlar | 10 times the strength of leather |
| Leather/canvas which is a composite material | This material is thin, stable and low density |
| Foam-blown polyurethane | This gives a shoe extra cushioning |
| Thermoplastic polyurethane | This makes a shoe both strong and pliable |
| Kangaroo leather | Gives a footballer that extra spring in his or her step. It offers good elasticity |
Question:
What exactly is a composite material?
When two or more materials with very different properties are combined
together they form a composite material.
The different materials work together to produce a new material, which
combines all of the properties of the previously separate materials. Within
the composite it is still possible to easily tell the different materials
apart. They do not tend to blend or dissolve into each other.
Composite Materials can be either man-made but they may also exist in
nature. Fibreglass and concrete are both composite materials.
Car tyres, mud bricks and drinks cartons are all made from composite materials.
To learn more
about Composite Materials click on: http://www.design-technology.org/comp1.htm
Stability
This is a material's resistance
to changes in shape and size.
Timber tends to 'warp' and 'twist' due to changes in humidity.
Plastics and metals deform when subjected to certain forces and stresses
for long periods of time.
The extension of a material under a load over a period of time is called
'creeping'.
Aeroplane turbine blades are exposed to high temperatures and rotational
speeds. It is important that they are made from creep resistant materials.
Elasticity
This is the ability of a material to bend and flex under the influence
of a force and regain its normal shape and size when the loads are removed.
A product with good elastic properties is an elastic band. Most structures
like bridges or buildings need to have this quality to a certain extent.
Buildings or bridges without this quality would tend to collapse if exposed
to high winds and extreme weather.
Density
Density can be explained as the amount of matter in an object (mass) has
per unit or space occupied by the matter (volume). Relative density is
the ratio of the density of a substance with that of pure water at a temperature
of 4 degrees centigrade.
Polyurethane is a unique material that offers the elasticity of rubber combined with the toughness and durability of metal. The flexible type of polyurethane is used to make upholstery, mattresses, earplugs, chemical-resistant coatings, specialty adhesives and sealants, and packaging. It also comes to the rigid forms of insulation for buildings, water heaters, refrigerated transport, and commercial and residential refrigeration.
This term is used to describe a materials ability to resist force without breaking or permanently bending. Different forces require different types of strengths to resist them. There are various types of strength such as tensile strength, compression strength, shearing strength, Torsional strength and bending strength.
The Properties of KEVLAR®.
KEVLAR® is one of the most important manmade organic fibres ever developed. Because of its unique combination of properties it is used today in a wide variety of industrial applications. The fibre possesses a remarkable combination of properties that has led to its use in a variety of commercial products since the 1970's
Fibres of KEVLAR® consist of long, interconnecting molecular chains produced from poly-paraphenylene terephthalamide.
General Features of KEVLAR®:
· High Tensile Strength at Low Weight
· Low Elongation to Break High Modulus (Structural Rigidity)
· Low Electrical Conductivity
· High Chemical Resistance
· Low Thermal Shrinkage
· High Toughness (Work-To-Break)
· Excellent Dimensional Stability
· High Cut Resistance
· Flame Resistant, Self-Extinguishing
Applications of KEVLAR
In the almost 40 years
since its discovery, Kevlar has many applications:
· Ropes that secure the airbags in the crucial landing apparatus
of the Mars Pathfinder
· Small-diameter, lightweight ropes that hold 22,000 pounds and
help moor the largest U.S. Navy vessels
· Shrapnel-resistant shielding in jet aircraft engines that will
protect passengers in case an explosion occurs
· Run-flat tires that allow for greater safety because they won't
ruin the rim when driving to the nearest assistance
· Gloves that protect hands and fingers against cuts, slashes and
other injuries that often occur in glass and sheet metal factories
· Kayaks that provide better impact resistance with no extra weight
· Strong, lightweight skis, helmets and racquets that help lessen
fatigue and boost exhilaration
Most of the teachers but probably not many of our students remember the rubber-soled plimsolls that were traditionally worn in PE lessons throughout most schools in Europe. 'You could have any colour you liked as long as it was black or white'.
These have been replaced by air cushioned, gel filled capsules with superior technical performance. They come in a variety of colours, shapes and forms and are purchased as much for their appearance as their performance.
The groundbreaking manufacturing technique that allowed the development of the plimsoll was called vulcanisation, which is still used today. This process uses heat to meld rubber and cloth together. Sulphur is used during the process.
Plimsolls were revolutionary at the time as they provided comfort, were lightweight and allowed the user to move around silently. Plimsolls became known as sneakers and were sold on a mass scale by the Keds Shoe Company in America as early as 1917.
You may think that spiked running shoes are a relatively new invention but they have been around for at least a 100 years. In 1890's a British company, which is now called Reebok created running shoes with spikes in them. The spiked shoe was developed out of necessity. The founder of the company enjoyed running and wanted to develop a shoe that would increase his speed.
In 1925 a company called Adi Dassler now known as Adidas created a range of shoes with hand-forged spikes. They offered a range of shoes for different distances. The company used the strongest and lightest materials available at the time to make the running shoes.
Adi-Dassler who founded the company Adidas, his brother Rudolph founded Puma.
In the 1970's sports shoe manufacturers employed experts to conduct research into how humans run. They also investigated the shock effect to the body caused by the collision between the feet and the ground. Their finding helped to develop new, improved sports shoes.
Their research found three types of running styles:
| Neutral: This is where the heel of the runner makes contact with the ground and the foot travels in a straight line as it moves forward. |
| Pronation: This where the heel hits the ground but this time the foot moves to the side as it travels forward. It refers to the inward roll of the foot. |
| Supenation: This is where the heel hits the ground and the foot rolls outward. |
Question: Have you ever examined the way in which
you run? Ask a friend to watch you run and ask them to decide which one
of the above you are. It is worth finding out before buying your next
pair of trainers as most are tailored to suit either Neutral, Pronation
or Supenation.
Modern technological developments
In your answer to the previous question you may have discussed materials
such as foam, silicon, air or gel. These have been used to create cushioning
systems in modern running shoes.
In the 1970's a plastic called 'ethylene vinyl acetate (EVA)' was developed.
This material revolutionised the construction of sports shoes. It was
made up of tiny air bubbles that provide cushioning and absorbs shock.
This material is injection moulded into shapes, which serve as heel supports.
To see a table of thermoplastics visit: http://www.design-technology.org/lesson4.htm
If you wish to find out more
about injection moulding check out the following web page:
http://www.design-technology.org/injectionmoulding3.htm
Following the introduction of Nike shoes, a technical breakthrough occurred in 1972 when Bill Bowerman, while studying the pattern on a waffle iron, came up with a great idea -- waffle soles. Bowerman then cooked some rubber in his waffle iron and glued it to the bottom of a pair of shoes, which he later gave to athletes to test. The athletes came back with great reviews and the sneakers were well received in the market. The patented outsole revolutionized running by offering better traction in a lighter-weight, more durable shoe.
Nike Air: The air bubble
Nike's Air technology, which used a gas-filled bag of air inserted in the sole of the shoe to cushion the impact of running, first appeared in 1979. The pair of sneakers was named; Tailwind and these technologically advanced air-soles had provided a good foundation for which further Nike advancements are based on. Since then, athletic shoes have become increasingly specialized and prices for various sneakers have grown in accordance to the advances in technology and its value-added features.
The basketball shoes below were sold in the 1980's and even included a pump valve. Customers were encouraged to pump up their trainers as if they were bicycle tyres. Purchase of the trainers included a pump.
Did you know?
In 2003 American spent on average 50 dollars (£28) on a pair of sports shoes.
Companies sponsor most top athletes. This means that they are paid a fortune to wear the company's products during a sporting competition.
The Olympics is the biggest sporting event in the world attracting worldwide television viewers. This offers an ideal opportunity for sports companies to get their products seen.
Questions:
Different types of sporting events require differently designed sports
shoes. Can you list a number of track or field events and then attempt
to describe the differences in the types of shoes used for these events.
You should be able to create specifications for each type of shoe.
You may consider borrowing a variety of sports shoes from the physical education department in your school and conducting a full product analysis.
How about conducting this simple test. Ask two equally matched runners to race against one another on a sports track. One of the runners uses spikes and the other uses ordinary trainers. Interview the two runners after the race and write down their comments.
The runner with the spikes
should feel that he had more grip on the track.
Sports shoe guide
The following table provides details about specific sports shoes. When
viewing the table consider how much trainer technology has advanced in
the last 100 years.
|
High
Jump
 |
This type
of shoe has a much thicker sole. This gives maximum support and comfort.The
shoe is light and flexible which helps the athlete achieve speed over
a short distance before jumping.This shoe has to have spikes. The
spikes at the front help the athlete to gain speed in the run-up.
The four spikes t the heel provide grip when the athlete takes off. |
|
Javelin
 |
This type
of shoe has to be robust and durable. Athletes drag their feet along
the ground during the throw. As a result the shoe has to be made from
a tough, hardwearing material. Support is crucial. Javelin shoes look
more like boots with protection around the ankle. Most of them feature
strapping. This prevents the foot from moving in the shoe. |
|
Jumps
and pole vault
 |
These events
require speed both on the ground and in the air. In most cases straps
have replaced the laces. The sole tends to be both firm and flexible
allowing extra bounce in the jump. The spikes are once again very
important. They provide the grip before the jump.Notice the spikes
tend to be just at the front of the shoe. |
|
The
Throws
 |
The shoe has
to allow the athlete to throw and spin. A hooked strap over the toe
helps to prevent the feet from moving sideways during the build up
to the throw.These types of shoes do not have spikes but have a hard
sole. This lengthens the lifespan of the shoe. The sole tends to have circular grooves on the balls of the feet. These help the athlete to spin |
|
Sprinting |
This
type of shoe has to be lightweight and offer flexibility at the front.
They all tend to have spikes, which are located at the front. They
are able to cope with lots of different types of surfaces. Most Olympic
Athletes have their shoes specially made. |
|
Long
Distance
 |
These shoes
have to be both durable and flexible. Comfort is a real priority,
also this about the sweat factor.A mesh is sometimes added in the
upper part of the shoe to allow the foot to breathe. The cushioning
is also very important.Spikes are sometimes added but are not essential. |
