MIT researchers have confirmed that specially-designed, spring-loaded prostheses don't give an advantage to disabled sprinters compared to runners with natural limbs.
By measuring the amount of force generated against the ground by the prosthetic legs, researchers concluded that the artificial limbs produced less energy than a regular human leg in every case.
That's an important finding, because the International Association of Athletics Federations in 2008 banned double amputee Oscar Pistorius from racing in that year's Summer Olympics. Pistorius' specially designed, spring-loaded prosthetic legs were deemed an unfair advantage over runners with natural limbs.
The ban was reversed later that year as a result of an MIT study that investigated Pistorius' limbs. Now, the findings in this wider study -- performed by the same MIT researchers -- confirm the original study's findings.
In the new study, the researchers gathered biomechanical data from six elite, unilateral (one lower-leg prosthesis, one biological leg) amputee sprinters who used running-specific prostheses.
Scientists analyzed data from jogging speeds up to top sprinting speeds on a high-speed instrumented treadmill at the Orthopedic Specialty Hospital in Salt Lake City, Utah. The researchers compared the forces exerted on the ground and step timing from the biological leg to the leg with the prosthesis.
Results showed that the primary determinant of top speed, the force applied to the ground, was 9 percent less in the leg with the prosthesis, impairing the amputees' top speed. They also found that the time required for the leg swing of a prosthesis was not different than that of a biological leg.
Here's a video of the test: