Do prosthetic limbs offer an unfair advantage in sporting competitions?

While I was attending a seminar in London, I decided to visit the Somerset House to check out the 2018 Sony World Photography Awards Exhibition. Although all the photographs were impressive, one in particular caught my eye. It depicted a man with prosthetic limbs on a running track. I started wondering whether these prosthetics could offer a mechanical advantage to amputees and whether they be allowed to compete alongside able-bodied athletes?

Oscar Pistorius, one of the most famous athletes of our time runs on specialized prosthetics, called “Cheetah Flex-Feet”. In 2008, an independent study[1] carried out at the German Sport University made a biomechanical and physiological analysis with Pistorius using his prosthetics and compared him with five able-bodied athletes who had similar levels of performance at 400m. This study noted that once a given speed has been reached, running with prosthetics needs 25% less energy and that the returned energy from the prosthetic blade is almost three times higher than with the human ankle joint. Therefore, Professor Peter Brüggemann concluded that running using Cheetah prosthetics allowed Pistorius to run at the same speed as his able-bodied peers with a lower energy consumption. Following this study, the IAAF[2] banned Pistorius from able-bodied competitions.

Soon after, biomechanist Roger Kram and biophysicist Hugh Herr investigated this perceived advantage and stated that Pistorius was “physiologically similar but mechanically dissimilar” to an able-bodied runner[3]. Their study found that, physiologically, there was only a negligible change in energy expenditure using Pistorius’ blades versus an able-bodied athlete’s ankle. The discrepancy between these two studies can however be attributed to different methods of calculation. Mechanically, Herr and Kram noted that Pistorius demonstrates faster leg swings because he can reposition his limbs 15.7% faster than most record holding athletes and that he requires less than half of the muscle force and 20% less ground forces to reach the same running speeds as able-bodied competitors[4]. According to Herr however, his tests show that “Pistorius’ blades allow him to run just as fast as he would have, had he been born with fibulas, but no faster”[5].

A third study, carried by Alena Grabowski at the MIT suggests that running with blades is a disadvantage because of the lower ground force, therefore making them slower and that is why amputees typically move their legs faster to generate the same amount of power[6].

In a nutshell, the Pistorius debate rests on whether his prosthetics increased the effectiveness of his appendages, allowing him to achieve higher speeds with less effort. Unfortunately, because of unreliable studies constantly contradicting each-other, the only certain advantage amputee athletes have is that they don’t risk any muscular or tendon injury that often trouble sprinters.

By decision effective since November 2015, IAAF has decided to refuse access to world championships to any athlete wearing prothesis, thus ending the Pistorius controversy, while hoping that “they will attend their own competitions”. The question of whether a carbon fiber prosthetic offers an unfair advantage may never be fully answered; we are still trying to understand what makes a runner faster and more efficient than another one.

I believe that this is not just a scientific debate. The only thing the above-mentioned studies have shown with certainty is that disabled athletes run differently than able-bodied runners and with technological advances, chances are we will one day create a prosthetic capable of outperforming the human body, leading up to the consideration of where to draw the line. This controversy also brings up a much more important, ethical dimension. If we are aiming to include the differently abled in our society, shouldn’t they be included in our sporting events? Isn’t it unfair that someone with enormous potential doesn’t get the chance to fulfill it because he was born different? Isn’t that the fairness we should be discussing? Sporting events celebrate physical prowess and what an accomplishment it is to become an Olympic medalist in sprint, especially without legs.


Marija Todorovic