5 October 2012
SAN FRANCISCO — When South Africa double amputee Oscar Pistorius
sprinted into history at the 2012 London Olympics, he had a lot of people to thank for the blades propelling him down the track. One is a San Diego-area engineer he’s never met: Hilary Pouchak.
Pouchak is among a small group of engineers–throwbacks, almost, to
an age of guild craftsmen–who pioneered the use of carbon fiber blades used for lower-limb amputees like Pistorius, whose nickname is the Blade Runner.
No electromechanical designs with force sensors and gyros. Just carbon blades using energy-storage potential principles.
“Using energy storage lower limb prosthetics is fundamental in bringing back something that’s been lost from that individual,” said Pouchak, whom I met during the Littelfuse Speed2Design event in Fontana in September.
Controversy has surrounded Pistorius because of the Flex-Foot Cheetah
blades, a situation that strikes many observers as absurd since the devices
allow a man who otherwise wouldn’t be able to even walk to run really,
Scientific American wrote:
One of the biggest points of contention is limb-repositioning time. The average elite male sprinter moves his leg from back to front in 0.37 second. The five most recent world record holders in the 100-meter dash averaged 0.34 second.
Pistorius swings his leg in 0.28 second, largely because his Cheetah’s are lighter than a regular human leg. Pistorius’s
rivals are swinging a lower leg that weighs about 5.7 kilograms,
whereas his lower leg only weighs 2.4 kilograms.
(During the London Olympics, Pistorius finished last in the 400-meter
semifinal, and his South African relay team finished eighth in the 4 x 400-meter relay. The sprinter was caught up in controversy a month later during the Paralympics when he complained about a competitor’s longer blade design).
Pouchak doesn’t get caught up in the controversy. Rather, like any
good engineer, he views the design challenge as a series of tradeoffs. What’s good and cost-effective for lower-limb amputees
isn’t necessarily the right solution for upper-limb amputations, for example. What works for certain types of amputations doesn’t always work for others.
Here’s Pouchak, trackside in Fontana, talking about the art, science and engineering that makes Oscar Pistorius run: