19 July 2007

An Oscar-winning performance

The debate surrounding Oscar Pistorius and whether he should be allowed to compete with able-bodied athletes has reached fever pitch. Does Oscar's bionic limbs count in his favour?

The debate surrounding paralympic gold medallist Oscar Pistorius and whether he should be allowed to compete with able-bodied athletes at the Beijing Olympics next year has reached fever pitch.

Just this week, the International Association of Athletic Federations said that Oscar's bionic limbs provide less air resistance than normal legs, according to the Associated Press.

Pistorius finished second in a B race in Rome last Friday. But against the elite field on Sunday, at the British Grand Prix, he was the last athlete across the finish line.

Does Oscar's prosthetic legs really count in his favour?

An early introduction to prostheses
According to Dr Ross Tucker, from the Sports Science Institute of South Africa, it's a question of excellent control in terms of balance, co-ordination and agility – actions that Oscar's brain learnt as a toddler when he was first introduced to prosthetic limbs.

He explains that during a child's development, the brain learns patterns in order to recognise exactly where the limbs are – a process called proprioception. For example, most people can close their eyes and still clap their hands without missing, because they learned the ability to sense where their limbs are over many years. "Walking and running involve a good deal of timing," Tucker says. "You have to know exactly when the foot is going to strike the ground in order to prepare for landing," and then for lift-off.

Many amputees, who lose limbs later in life, first have to unlearn these commands, and then learn new ones. Tucker notes that Oscar had the opportunity to learn proprioception while using prostheses from a very young age. It is possible that he knows exactly when the foot is about to touch the ground, based on other signals sent from, say, the upper thigh where the prosthesis attaches. He also didn't have to "overwrite" previous patterns when he learnt to walk – a problem that amputees generally encounter when they lose a leg later in life.

Advantages in terms of rhythm
Adding to this advantage is the fact that Oscar is a double-leg amputee. This has advantages in terms of rhythm – an aspect that plays a particularly important role in running the sprints, says Corné Rossouw, Adapted Physical Activity Specialist of the Department of Human Movement Science at the University of Stellenbosch. She says that Oscar's rhythm when running is better than that of a single-leg amputee.

However, Oscar's overall balance cannot be compared to that of an able-bodied athlete.

"He has nothing like the fine motor control that is added by having a calf, ankle and foot," Tucker says. When Oscar is running, he has no contribution from the muscles in the lower leg, particularly around the ankle, which all contribute to balance.

This might explain Oscar's relatively slow starts and why he staggered and almost lost his balance about 10m from the finishing line in the Athens Olympics 200m final. "Oscar doesn't have that clear a feeling of the amount of force that he needs to apply to get away from the blocks," Rossouw says. According to Tucker, Oscar's postural control must be exceptionally good to compensate for this.

A 'well-connected' athlete
Oscar's pair of prosthetics were made by the former 200m world-record holder, Brian Frasure.

"I heard a Russian expert on biomechanics once refer to certain people as 'well-connected' if they were able to learn new techniques or skills very easily. Oscar would be exceptionally well-connected, because it seems he is able to adapt to new prosthetics and learn balance very well," Tucker says.

According to Rossouw, who worked with Oscar to help him adapt to his new set of prostheses, the new legs did, however, take some getting used to. Oscars' previous prostheses were much harder than his current racing set and the signals sent to the brain during running would therefore be very different.

Could Oscar compete in the Olympics?
Despite the unique compensations that Oscar's body has had to make, he has already shown that he could compete against able-bodied Olympic champs.

"If you consider how slowly Oscar starts those races, it's possible that at his top speed, he is running as fast as the world's fastest able-bodied guys. I'm speculating, but it would be interesting to see if Oscar's top speed is comparable to the top speed of Shaun Crawford. I suspect that it is very close," Tucker says.

It is possible that the prostheses add distance to his strides and that this could count in his favour. But both Tucker and Rossouw agree that any possible advantages still won't make up for Oscar's disadvantages in terms of balance and rhythm.

As for whether he will ever reach world-class at an able-bodied level, Tucker's gut feel for the 100m and 200m is no. "I think that the reduced balance and slow starts are obstacles that are too big to overcome." Tucker speculates that Oscar might have a better chance in competing in the 400m able-bodied event. – (Carine van Rooyen, Health24)

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