08.01.12
It’s almost impossible to imagine that a double-amputee running in the Olympic Games would face criticism. Nonetheless, that’s what South African Olympian Oscar Pistorius has had to face during the past several years, ever since 2007 when the International Association of Athletics Federations (IAAF) banned him from competing against able-bodied runners. His carbon fiber prosthetic legs manufactured by Icelandic company Össur were said, and still are said, to give him an “unfair advantage” on the track.
Headquartered in Monaco since 1993, the IAAF is the international governing body for athletics. On March 26, 2007, the organization changed its rules to ban the “use of any technical device that incorporates springs, wheels or any other element that provides the user with an advantage over another athlete not using such a device,” although the IAAF insisted the rule change did not target Oscar Pistorius specifically. The IAAF observed Pistorius in races that year with high-definition cameras, and concluded that Össur’s Cheetah Flex-Foot did indeed give him an advantage. In January 2008, the IAAF disqualified him from competing in any sport even that it has governance over, which included the 2008 Olympic Games in Beijing, China.
Pistorius didn’t give up. He appealed the IAAF’s decision to the international Court of Arbitration for Sport (CAS), which overturned IAAF’s decision in May 2008. The court decided that because the IAAF observed Pistorius running at full speed in a straight line, it did not take into consideration the disadvantages he would face in a real 400 meter race, which is on a circular track.
Photo credit: Michael Steele/Getty Images
“This is one of the best days of life,” Pistorius said after the IAAF decision was overturned. But this wouldn’t be the end of the obstacles the so-called “Blade Runner” would face.
He didn’t qualify for Beijing in 2008, but four years later Pistorius is back in the spotlight. This summer he will compete in both the Paralympic Games and the Olympic Games in London, United Kingdom—the first amputee to ever compete in the Summer Olympics. And again, critics have emerged to say he will have an unfair advantage over his able-bodied competitors.
So what’s the story behind the controversial prostheses? The Cheetah Flex-Foot is custom built by Össur for each customer, and has a springiness to it that imitates the propulsion given by the complex motion of ankle and foot muscles and joints. Vertical forces generated at heel contact are stored and translated into a linear motion described as Active Tibial Progression. This action reduces the need to actively push the body forward using the contralateral foot and also equalizes stride length. The layering of carbon fiber, optimized through extensive computer analysis and mechanical testing, ensures that the deflection of the carbon fiber heel and forefoot components are proportional to the user’s weight and impact level.
The Össur prosthetic is indicated for transfemoral and transtibial amputees, and are specifically manufactured for use in sports. The prosthetic, as seen in the picture, is not styled to look like a biological leg or foot. It is a J-shaped molded piece of carbon fiber designed for optimum performance in running. When a user is running, the prosthetic’s "J" curve is compressed at impact, storing energy and absorbing high levels of stress that would otherwise be absorbed by the runner’s ankle, knee, hip, and lower back. At the end of stance phase, the "J curve" returns back to its original shape, releasing the stored energy and propelling the user forward.
The propulsion is what has critics riled up more than anything. Although it mimics natural foot motion closely, there are no muscles present where the lower leg would be. This means the runner does not have to supply oxygen to that region of the body, freeing up more oxygen to fuel the rest of the body.
Hugh Herr, director of the Biomechatronics Group at the Massachusetts Institute of Technology, differs with critics. As they currently exist, he says, artificial legs actually have more of a metabolic cost than biological legs. In the future, perhaps within the next decade, there may be prosthetic legs that make it easier to run than with biological legs, but that time has not come yet.
“In the future, when we have truly advanced systems, there will be an Olympic-sanctioned leg, just like the Cheetah now at the Olympics, and that leg will truly emulate flesh and bone,” Herr told The New York Times. “But technology may be so vast and sophisticated that there will be a limb that can extend beyond what nature intended, and that will certainly be used in the Paralympics—decrease running time, increase jumping time, beyond what nature is capable of.”
Prosthetic feet, like shoes, are designed for specific activities. Running or participation in other sports with a normal prosthetic foot can cause discomfort and potential injury. It also may be fatiguing to the user, typically requiring they expend disproportionately higher amounts of energy. Because Össur's Cheetah is specifically designed for running, it allows amputee athletes to train more effectively and with less risk of injury than if they used prosthetic feet designed for normal daily activities, claims the company. The smooth reaction and dampening effect of the Flex-Foot Cheetah also allows the user to focus on the task at hand, and not on what the foot is doing—a benefit able-bodied athletes enjoy without even thinking about it.
"With this extraordinary accomplishment, Oscar Pistorius has achieved what no other lower-limb amputee has ever done, and helped make Össur's Flex-Foot Cheetah a household name. As the ‘Blade Runner,’ he is one of the most recognized and influential amputees in the world, embodying what it means to live life without limitations," said Jon Sigurdsson, president and CEO of Össur. "We are inspired by all he has accomplished, and humbled that he chooses to wear Össur prostheses both on and off the track. We wish Oscar continued success as he claims his place in the pantheon of athletic greatness and enters the world stage of athletic competition."
According to Össur, the technology used in the Cheetah has not been updated significantly since 1997 when it was first introduced.
Pistorius will not be the only person on London soil running with “blades” for feet. BBC producer Stuart Hughes, who lost a leg reporting in Iraq, ran on his athletic prosthetic, a very similar carbon fiber foot made by British company Blatchford, in part of the Olympic torch relay.
“The process has made me appreciate what an amazing machine the human body is,” Hugh said, highlighting how important it is to understand that it is the body powering the prosthetic rather than the prosthetic powering the athlete.
Pistorius would agree. Refusing to be defined how others want to define him, his motto is, “You're not disabled by the disabilities you have—you are able by the abilities you have.”
An interview with Pistorius can be viewed here, courtesy of The Guardian.
Headquartered in Monaco since 1993, the IAAF is the international governing body for athletics. On March 26, 2007, the organization changed its rules to ban the “use of any technical device that incorporates springs, wheels or any other element that provides the user with an advantage over another athlete not using such a device,” although the IAAF insisted the rule change did not target Oscar Pistorius specifically. The IAAF observed Pistorius in races that year with high-definition cameras, and concluded that Össur’s Cheetah Flex-Foot did indeed give him an advantage. In January 2008, the IAAF disqualified him from competing in any sport even that it has governance over, which included the 2008 Olympic Games in Beijing, China.
Pistorius didn’t give up. He appealed the IAAF’s decision to the international Court of Arbitration for Sport (CAS), which overturned IAAF’s decision in May 2008. The court decided that because the IAAF observed Pistorius running at full speed in a straight line, it did not take into consideration the disadvantages he would face in a real 400 meter race, which is on a circular track.
Photo credit: Michael Steele/Getty Images
“This is one of the best days of life,” Pistorius said after the IAAF decision was overturned. But this wouldn’t be the end of the obstacles the so-called “Blade Runner” would face.
He didn’t qualify for Beijing in 2008, but four years later Pistorius is back in the spotlight. This summer he will compete in both the Paralympic Games and the Olympic Games in London, United Kingdom—the first amputee to ever compete in the Summer Olympics. And again, critics have emerged to say he will have an unfair advantage over his able-bodied competitors.
So what’s the story behind the controversial prostheses? The Cheetah Flex-Foot is custom built by Össur for each customer, and has a springiness to it that imitates the propulsion given by the complex motion of ankle and foot muscles and joints. Vertical forces generated at heel contact are stored and translated into a linear motion described as Active Tibial Progression. This action reduces the need to actively push the body forward using the contralateral foot and also equalizes stride length. The layering of carbon fiber, optimized through extensive computer analysis and mechanical testing, ensures that the deflection of the carbon fiber heel and forefoot components are proportional to the user’s weight and impact level.
The Össur prosthetic is indicated for transfemoral and transtibial amputees, and are specifically manufactured for use in sports. The prosthetic, as seen in the picture, is not styled to look like a biological leg or foot. It is a J-shaped molded piece of carbon fiber designed for optimum performance in running. When a user is running, the prosthetic’s "J" curve is compressed at impact, storing energy and absorbing high levels of stress that would otherwise be absorbed by the runner’s ankle, knee, hip, and lower back. At the end of stance phase, the "J curve" returns back to its original shape, releasing the stored energy and propelling the user forward.
The propulsion is what has critics riled up more than anything. Although it mimics natural foot motion closely, there are no muscles present where the lower leg would be. This means the runner does not have to supply oxygen to that region of the body, freeing up more oxygen to fuel the rest of the body.
Hugh Herr, director of the Biomechatronics Group at the Massachusetts Institute of Technology, differs with critics. As they currently exist, he says, artificial legs actually have more of a metabolic cost than biological legs. In the future, perhaps within the next decade, there may be prosthetic legs that make it easier to run than with biological legs, but that time has not come yet.
“In the future, when we have truly advanced systems, there will be an Olympic-sanctioned leg, just like the Cheetah now at the Olympics, and that leg will truly emulate flesh and bone,” Herr told The New York Times. “But technology may be so vast and sophisticated that there will be a limb that can extend beyond what nature intended, and that will certainly be used in the Paralympics—decrease running time, increase jumping time, beyond what nature is capable of.”
Prosthetic feet, like shoes, are designed for specific activities. Running or participation in other sports with a normal prosthetic foot can cause discomfort and potential injury. It also may be fatiguing to the user, typically requiring they expend disproportionately higher amounts of energy. Because Össur's Cheetah is specifically designed for running, it allows amputee athletes to train more effectively and with less risk of injury than if they used prosthetic feet designed for normal daily activities, claims the company. The smooth reaction and dampening effect of the Flex-Foot Cheetah also allows the user to focus on the task at hand, and not on what the foot is doing—a benefit able-bodied athletes enjoy without even thinking about it.
"With this extraordinary accomplishment, Oscar Pistorius has achieved what no other lower-limb amputee has ever done, and helped make Össur's Flex-Foot Cheetah a household name. As the ‘Blade Runner,’ he is one of the most recognized and influential amputees in the world, embodying what it means to live life without limitations," said Jon Sigurdsson, president and CEO of Össur. "We are inspired by all he has accomplished, and humbled that he chooses to wear Össur prostheses both on and off the track. We wish Oscar continued success as he claims his place in the pantheon of athletic greatness and enters the world stage of athletic competition."
According to Össur, the technology used in the Cheetah has not been updated significantly since 1997 when it was first introduced.
Pistorius will not be the only person on London soil running with “blades” for feet. BBC producer Stuart Hughes, who lost a leg reporting in Iraq, ran on his athletic prosthetic, a very similar carbon fiber foot made by British company Blatchford, in part of the Olympic torch relay.
“The process has made me appreciate what an amazing machine the human body is,” Hugh said, highlighting how important it is to understand that it is the body powering the prosthetic rather than the prosthetic powering the athlete.
Pistorius would agree. Refusing to be defined how others want to define him, his motto is, “You're not disabled by the disabilities you have—you are able by the abilities you have.”
An interview with Pistorius can be viewed here, courtesy of The Guardian.