The Blade Runner and the Burden of Proof

The changing rules for elite athletes who run on prostheses tell us something really important about science in policy and ourselves as well

Last week the Court of Arbitration for Sport (CAS) quietly issued a landmark decision. The case pitted Blake Leeper, an American sprinter who runs on prostheses having been born without lower legs, against the International Association of Athletics Federations (IAAF, now called World Athletics). Leeper has an accomplisher career in Paralympic competition and now was seeking the right to compete in the Tokyo Olympics.

It was a complicated case, involving confusing rules and contested science, but in the end Leeper lost his appeal to run in Tokyo. However, the lasting significance of the ruling goes beyond one athlete — it has opened a previously closed door for other amputees to participate in Olympic athletics competition.

In addition, at the core of the ruling is an important lesson about uncertainty in science. How we choose to act in the face of irreducible uncertainties not only reflects our values, it is defined by them. It shows who we are, and who and what we value.

To understand this issue, we have to go back in time to the 2008 CAS case of Oscar Pistorius, the South African sprinter who competed in the 2012 London Olympic Games (and who was later convicted of murder). Before competing in the 2012 Olympics, Pistorius was initially barred from competing in IAAF events, because the IAAF claimed that as a “blade runner” he received an unfair advantage over other athletes due to his use of prosthetic legs.

Pistorius took IAAF to the CAS, which upheld his appeal, enabling him to qualify for and compete in the London games. Understanding why Pistorius won his case requires a quick primer on science and IAAF rules.

It turns out that the science of running is both fascinating and complicated. To assess the relative advantage a runner using prostheses might have over another runner (or even the hypothetical version of themselves in an alternate universe where they were not amputees) requires among other things quantifying force, acceleration and speed. Sprinting involves leaving the blocks, accelerating, rounding a curve — with different effects depending on whether the athlete’s prosthesis is on the inside or outside leg, or both — and straightaways. Research indicates that different types of prostheses and different uses of the same prosthesis (e.g., its height) result in different advantages and disadvantages for para athletes. It is possible that what happens in a lab setting is not identical to what happens in competition. Of course there are many uncertainties — it is complicated!

In 2008, these many uncertainties involved in quantifying what if any advantage Pistorius had over other runners meant that in his case versus IAAF the CAS was unable to conclude with necessary certainty that Pistorius received a net advantage via his use of the “blades.” And here is where it gets really interesting. Because the burden of proof was, at the time, on IAAF to show that an athlete received an advantage in order to justify their exclusion, that meant that scientific uncertainty in this instance was resolved in favor of inclusion. Pistorius was thus allowed by CAS to run in the Olympics.

Following this ruling, the IAAF changed its rules, and placed the burden of proof upon the “blade runner” (or jumper) wanting to run in the Olympics to demonstrate that they did not gain an advantage from their use of prostheses. In practice, this created an insurmountable burden for athletes — not only is proving a negative essentially impossible in this context, the rule would require that an athlete oversee and fund a cutting-edge international research program. Changing the burden of proof from the IAAF to the athlete turned an opportunity for inclusion to what was in effect a ban on participation.

Not surprisingly, other Paralympians with Olympic dreams were unable to meet the impossible burden of proof, and to this day Pistorius remains the only athlete on prostheses to compete in the IAAF World Championships or the Olympics. But things have again changed.

In the CAS ruling on Leeper last week, the panel recognized that placing the burden of proof upon the athlete to show no advantage was in effect a ban on their participation. Since the Olympics are, in principle, about inclusion the CAS panel changed the IAAF rules, once again placing the burden of proof back upon IAAF — if the IAAF wishes to exclude a “blade runner” from competition, then going forward it has to provide evidence (on the balance of probabilities) that the athlete receives an unfair competitive advantage. (It was on this basis that CAS ruled against Leeper.)

The CAS panel criticized the IAAF for spending more time focused on how to exclude Paralympic athletes from their competitions, rather than developing rules and criteria to facilitate their inclusion. Now, the burden of proof for exclusion is back on the IAAF, meaning that uncertainty will be resolved in favor of inclusion, as it was with Pistorius.

A broader lesson of the evolving rules governing “blade runners” in elite sport is to show us that how we act in the face of irreducible uncertainties reveals our underlying values. For the IAAF where the burden of proof resides reveals whether the institutional default is exclusion or inclusion. The IAAF even admitted this explicitly, likening its exclusionary stance to the “precautionary principle” typically invoked is the context of pollutants and other impurities.

Going forward, we should now expect more “blade runners” (and jumpers) to seek qualification for participation in the World Championships and Olympics — and to succeed in seeking inclusion. They should, as these competitions are expected to be inclusive of everyone. There are now strong incentives for the IAAF to, at long last, develop technical criteria for inclusion for athletes who run on prostheses. There is no obstacle to developing such criteria — of course the Paralympics does this all the time, and we should expect specific criteria to be debated, discussed and negotiated.

Ultimately, how we act in the face of uncertainties reveals who we are and who we wish to be. When complex decisions are made, science and values are always present. Sometimes, it is just hard to see them clearly.