One of the leading prosthetic companies explains the physics behind Olympian Oscar Pistorius' running blades.
A computer monitoring her stride flickers as she puts one step down on her flesh-and-blood leg, another on her carbon fiber prosthetic – again and again and again. Ever since Bassett got her first athletic prosthetic, she's been addicted to sports.
"Sports was something that made me feel whole. It sounds a little ironic, but when I was out there, even if I wasn't playing, just being out there with other people made me feel like I didn't notice my disability really," she said.
Today, Bassett, 23, is a top para-triathlete who works in digital media at Ossur's office in Foothill Ranch in Orange County.
Ossur is the brand that manufactured prosthetic legs for Oscar Pistorius, the South African who will be the first double amputee to run in the Olympics. Pistorius was initially banned from the 2008 games. The Court of Arbitration for Sport (CAS) deemed that his blades, known as Flex Foot Cheetahs, gave him an unfair advantage. CAS eventually overturned its original decision to ban him before the Beijing Games, but Oscar failed to make the qualifying time that year.
"You know, a lot of people think you put on these Cheetah leg blades and you're running record times. It's definitely not that easy because, if it was, then every Paralympian would be competing in the Olympics," Bassett said.
The first Flex-Foot blades came out in 1997 and have become the limb of choice for many Paralympian sprinters. But prosthetic technology dates back long before the first Olympics. Perhaps the earliest evidence of a prosthesis is a wooden toe attached to a female mummy that dates to around 950BC and 710BC in ancient Egypt. In the Victorian era, amputees could choose from limbs made of ivory, leather and vulcanized rubber.
But historically, there wasn't a big market for the limbs – before doctors used antiseptics, most major amputations ended in death.
As medical practices improved and wars left veterans without limbs, the demand for prosthetics rose. Ossur, launched in 1971, has become an industry leader. Company prosthetist Coryn Rich explains the design behind the j-shaped blades.
"The design of the Flex-Foot Cheetah was basically [...] to mimic the anatomical foot and ankle motion. It does not look the same, however the function of it is as similar as possible," she said.
The physics behind the movement of a sprinter using on a flex foot Cheetah versus another sprinter with an anatomical leg are about the same. In both cases, the athlete exerts high forces on the ground through their toes, the balls of their feet or the front of their blade, and that force propels them forward.
"As the energy is loaded into the prosthetic foot into the Cheetah, that j-shape compresses and then the carbon fiber springs back and allows for energy return to the amputee then running on it," Rich said.
Able-bodied runners can get about 240 percent energy return from their flesh-and-blood legs. The Cheetahs return a mere 90 percent of the energy expended. Runners who use them have to make up for that difference by moving their legs faster and pushing harder off the ground to get more thrust.
Scout Bassett trains for four hours daily and today she's sprinting on a track near Ossur. This year she didn't qualify for the Paralympics, which will be held in London immediately following the Olympics. But she's training hard for other international competitions and the 2016 games.
Bassett hasn't always had the luxury of using the prosthetic blades. As a child in China, she lost her right leg in a chemical fire. Her parents abandoned her at an orphanage.
"Actually, the orphanage did give me a prosthesis, but it was made of leather belt straps. The foot was taped on by masking tape. It wasn't even functional, so I didn't even use it because it was more difficult to have it," she said.
After she was adopted, Bassett put on her first Ossur foot at age eight. She applied for grants to get athletic prosthetics when she was fourteen.
Runners like Bassett and Pistorius aren't typical Ossur clients. Most of the company's prosthetics go to patients who suffer amputations due to diabetes or war injuries. Ossur's sales boomed as the wars in the Middle East sent home scores of soldiers who lost arms or legs.
Veterans are especially interested in bionic limbs equipped with microprocessors. These prosthetics adapt to individual walking styles and different environments.
Right now, no one will be allowed to compete in the Olympics or Paralympics with motorized parts or bionic limbs. But as the technology continues to develop, the prospect of a cyborg Olympics might not be too far fetched.
Correction: An earlier version of this story reported that Oscar was entirely banned from the 2008 games.