Silicon Valley Nation: What makes Oscar Pistorius run?
10/4/2012 2:46 PM EDT
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 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, who 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,
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
Here's Pouchak, trackside in Fontana, talking about the art, science and engineering that makes Oscar Pistorius run: