Football Boots to Soccer Slippers
In
the early days football boots weighed approx. 500 grams when
dry and twice as much when wet. When manufacturers were made
aware the boot was only in contact with the ball for about 10%
of the game, they developed less heavy boots. Lighter footwear
meant players were less exhausted and subsequently the overall
speed of play increased. This made for a more enjoyable spectator
sport. The soccer boot was streamlined with the ankle hugging
component reduced to below the malleoli (anklebones). At first
this met with concerns about ankle injuries, but this proved
ill founded. The traditional soccer boot was now a slipper or
soccus. Leather soles were first replaced by moulded rubber,
and then injection moulded PVC before eventually nylon and plastic
provailed. The new synthetic materials were waterproof, cheap
to produce and substantially lighter than leather. The upper
of the slipper became thinner improved treatment of leather
with synthetic waterproof compounds contributed to the development
of the new styles.
The
physical properties of kangaroo skin were recognised very early
in the 19th century and most quality sports footwear was made
from the marsupial's skin. This tradition has quietly continued
in soccer shoes and now most quality shoes are now made from
medium brown, vintage kangaroo leather. This is a name given
to the process of tannage (preparing the leather) and often
the leather is dyed to popular dark colours. Kangaroo hide is
the toughest and most durable available and been used to produce
quality sports shoes for rugby, American football, baseball,
basketball, tennis and cycling shoes for over a century. It
is lightweight yet very strong and many times stronger than
the same thickness of cowhide. Comfortable and supple it requires
no break-in period and gives the player a tight fit with optimal
feel for the ball. Suitably treated Kangaroo leather is favoured
because of its high performance nature. Kangaroo leather has
a naturally high strength-to-weight ratio. In the 80's, Australia's
CSIRO under took independent tests which confirmed these findings
and determined that, when shaved to 20% of its original thickness,
kangaroo leather retains between 30% and 60% of its original
tensile strength, as compared to a retention rate of 1% -4%
for calf and bovine leathers. In a further study by the CSIRO,
it was found that kangaroo leather was at least 50% stronger
than goatskin gloving leather in tear strength and puncture
resistance. Microscopically the hide displays high uniform orientation
of fibre bundles in parallel with the skin surface. The skin
of the Kangaroo does not contain sweat glands or erector pili
muscles, which would weaken the skin surface. The yellow elastic
fibres (elastin) are evenly distributed throughout the skin
thickness which gives the leather greater tenacity. These properties
remain even when the leather is split. Tanning further enhances
the leather's properties by unsticking the fibre bundles thereby
allowing them to move independently. Their recent popularity
may be explained by "Foot & Mouth " and Mad Cow Disease
scares. Whilst recent animal rights activists have brought the
use of kangaroo skin to the public's attention by condemning
players like David Beckham, who endorse their use reputable
firms collect kangaroo hides during the Kangaroo Harvest. Environment
Australia - Wildlife Protection (an Australian Federal Government
agency whose job it is to regulate and control the harvest and
manufacture of all kangaroo leather) regulates this with the
ruling that only non-endangered species can be used. Today's
boots weigh less than 250gms eg Mercurial Vapour (NIKE) - 196
gms. Development of latex foam, meant the soccer shoe could
be cushioned at no detriment to overall mass and new lightweight
synthetics were stronger and harder wearing than traditional
soles. According to Grau (1997) the focus of boot research from
the 70s has been primarily directed at anti-pronatory control
(preventing the foot from rolling over0. This was combined by
using cushioning mechanisms to damped shock to the foot. Later
researchers looked at torsion and pressure distribution across
the foot. Initially it was wrongly assumed overloading of the
weightbearing foot was the primary cause of most injuries. This
research led to shoe design thought to cope with the problems
but the number of reported injuries did not decrease. Moreover
it seemed, in retrospect, many reported injuries arose as a
result of the injury preventing solutions in boot design. Many
injuries are attributed to adverse physical conditions at the
interface between the soccer shoe and the playing support surface.
The function of the soccer boot provides some means of attachment
to the playing surface whilst encasing the foot for protection.
No shoe can ever guarantee full protection against injuries,
because there exists a conflict between the function of the
shoe and the interests of the human body. The maintenance of
static balance for a player performing an individual skill demands
a significant level of torque. Excess torque or twist passes
proximally through the foot pedestal to damage the ankle or
knee. During contact, a static foot anchored to the ground negates
its ability to dampen down (shock absorb) external forces, such
as caused by contact with another player. The ankle and knee
then have to absorb the energy of impact, alternatively torque
within the short bones of the foot may cause them to fracture.
This type of incident was illustrated by recent injury to David
Beckham (Manchester United & England). Such great store
is placed on individual players of his calibre that in the FIFA
World Cup Korea Japan game against Sweden in the openning round,
he wore a special supportive sole in his boot designed to give
maximum Ironically the custom-made footwear was made by a Swede,
called Jorgen Wiklander. It has also become the player's custom
to wear a new pair of the now famous silver boots for each game
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