- The athletes who take the field in next
year's Paralympic games are among the pioneers showing how technology -
from prosthetics to sophisticated robotics - can be melded with the human
body to improve performance. Hari Kunzru reports
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- AS competitors get ready for next year's
Sydney Olympics, preparations are also underway for the Paralympics, which
start soon after the mainstream competition finishes. Four thousand athletes
from 125 countries will take part in a sporting event that, even more than
its able-bodied sibling, demonstrates the effects new technologies are
having on the human body.
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- It has become fashionable to call sports
stars the first cyborgs. Scientific training regimes, diet and specialised
equipment are all ways of augmenting human performance through technology,
and despite the Olympic ideal of "pure" physical competition,
the temptation to improve performance by chemical means is becoming too
great for many athletes.
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- But although able-bodied sports people
find themselves in an ever-closer relationship with technology, the true
cyborg pioneers are the disabled. In such events as swimming, competitors
must not use "artificial devices", but in many others, notably
wheelchair sports and amputee track and field events, participation would
be impossible without high-specification prosthetics and other equipment.
It is no exaggeration to say that in many Paralympic events, entrants compete
as amalgam of human and machine.
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- The growing prestige of the Paralympic
movement is primarily based on the performances of disabled athletes, which
have improved dramatically over the past few years. American track and
field star Aimee Mullens had her feet amputated at the age of one, but
recently set an unofficial 200m record of 34.06 seconds (Florence Griffith-Joyner's
two-footed world record time was 21.34 seconds). Seven times world discus
record holder Shawn Brown says: "I can throw farther now than when
I had two legs." His throw of 54.2 meters is still less than the world
record of 74.08m, but considering Brown's left leg is amputated below the
knee, it is a substantial achievement.
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- Underlying Brown's performance is a lot
of training, mental toughness, and a significant technical development.
The complex turning and spinning motion required in discus throwing is
made possible only by an extremely sophisticated prosthetic leg and foot
assembly, a rig that owes more to the aesthetics of The Terminator than
the "peg-leg" of popular cliché. Peter Pan pirates aside,
prosthetics have come a long way from wooden legs and hook hands. The equipment
used by high-scoring Paralympians depends on advances in CAD/CAM (computer-aided
design/computer-aided manufacturing), 3D modelling and biomechanics, materials
science, and hydraulics. It may even incorporate robotics, embedded computers,
and that staple of science fiction, true interfaces between flesh and machine.
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- To illustrate, let's build a cyborg leg
. . . The first issue is to decide how to connect the leg to its wearer.
A hundred years ago, fitting a socket involved some leather straps, a piece
of hardwood and a lot of chisels and sandpaper. Prosthetic legs were either
bought "off the shelf" with a more or less round socket, or if
you were lucky, had some degree of customisation, involving a little shaving
here, a little sanding there.
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- The result was often excruciatingly painful
for the wearer, and tended to cause the stump to atrophy. Now hi-tech prostheticians
can put a patient's residual limb into a 3D scanner, gaining a complete
computer model that is used to design a socket as individual as the wearer.
The design is also modelled on computer, then output directly to a robotic
milling tool, essentially the same operation as getting a print-out of
a word-processor document.
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- Instead of wood, it is more likely to
be made of less rigid plastics that allow the remaining limb muscle to
grow and distribute the weight evenly over its surface. Straps still play
a part in keeping some legs on, but various types of suction cup are also
in use. In a recent development, some European doctors have begun to attach
prosthetics directly into the thigh bone.
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- Next, to the knee. Artificial knee-joints
- themselves an advance on jointless wooden or metal legs - once consisted
of a metal hinge and a couple of rubber pads to absorb impact. Fine in
theory, but the friction of strenuous activity could cause the whole assembly
to melt.
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- The knee's movement is also far from
being a straightforward one-dimensional bending. Today's prosthetic knees
are designed to minimise friction and allow the user to walk naturally,
using cushioning and bearings. Here, the technical advance lies less in
the object than the design process. Biomechanics, the study of human motion,
has become big business. Computer games designers, cinema special effects
houses and sports shoe manufacturers all have a stake in it.
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- Architects, designers of cars, factory
production lines, furniture and computer equipment also use detailed information
about the way we move. This information is gained through video and computer
analysis, and the same data that drives prosthestics design is likely to
be animating the goons in the next SF flick you see, and dictating the
height and position of the pedals in your new car.
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- The knee bone is, as they say, connected
to the shin bone, and it is here, in this seemingly straightforward part
of the leg, that one is most likely to find embedded intelligence. The
sub-discipline of biomechanics known as gait analysis has shown that the
swing of our lower legs when walking is radically different from that when
running, and a slow walk is different from a fast one.
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- Until recently, artificial leg-wearers
had to "kick" their lower legs forward to get a greater swing,
creating an unnatural and unstable motion. Now hydraulics can produce far
better motion, and it is here that computers come in. When fitting a leg,
the prosthetician programs a chip embedded in the shin cylinder to sense
changes in speed and adjust the leg hydraulics accordingly.
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- The shin mechanism connects to the foot,
which, being the contact with the ground, has to work hard. As with many
aspects of prosthetic design, war has played a big part in driving foot
design forwards, in this case the use of landmines in Vietnam. It was in
response to the poor quality of the rubber and plastic feet available to
the huge population of active young veterans disabled by such weapons that
American doctors turned to carbon fibre. A simple curve of carbon fibre
provides a remarkably efficient foot mechanism, returning up to 95 per
cent of downwards energy, which reduces fatigue and improves athletic performance.
The artifical legs used by top Paralympians are integral to their performances.
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- This is just one aspect of current prosthetics
technology, which now extends to optical aids for the blind, artificial
arms controlled by electrical impulses from the wearer's muscles, and robotics
for the severely disabled. As we inch towards the augmented human-machine
hybrids of the future, disabled people are leading the way.
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