INTRODUCTION
When Oscar Pistorius crossed an Olympic starting line in 2012, he settled one question whether a double amputee could race against able-bodied athletes and left another wide open: what legal standard should govern a sport’s decision to treat a prosthetic limb as equipment rather than a body part? More than a decade on, that question still has no clean answer, and the reason is only partly scientific. It is also a story about the limits of private regulatory power, the burden of proof in sports arbitration, and a classification formula now shown to carry a demonstrated demographic bias.
LEGAL FRAMEWORK FOR DISABILITY IN ATHLETIC SPORTS
Athletics, like most Olympic sports, is governed not by national legislation but by a layered system of private rules, World Athletics (formerly the IAAF) at the able-bodied level, World Para Athletics (under the International Paralympic Committee) at the Paralympic level, with the Court of Arbitration for Sport (CAS) in Lausanne as the final appellate body for eligibility disputes. This is lex sportiva: a body of rules created and enforced by sports federations themselves, reviewable by CAS and, in narrow circumstances, by the Swiss Federal Tribunal, since CAS is domiciled in Switzerland. An athlete challenging a federation’s technical ruling does not sue under ordinary civil or human rights law in the first instance; they invoke a private arbitration clause typically accepted as a condition of competing.
That structure matters because it shapes what an athlete can actually contest, and on what evidentiary terms, as the disputes below illustrate.
PISTORIUS AND THE BURDEN OF PROOF
In 2007, the IAAF commissioned a study at the German Sport University in Cologne. Researchers concluded that Pistorius’s prosthetics gave him a significant mechanical advantage, estimated at around 30 percent over an able-bodied runner with comparable sprint times and healthy ankles. Based on that finding, the IAAF ruled his blades a prohibited technical aid and barred him from IAAF competitions.
Pistorius appealed to CAS 1. His legal team argued the Cologne study only measured him at top speed and ignored the disadvantage he faced out of the blocks, where amputee sprinters cannot generate the same push-off force as an intact leg and foot. Sports scientists had found he could hold the same speed as non-disabled athletes while using 25 percent less energy, which was treated as the unfair advantage, but Pistorius’s team countered that the full picture had to include the slower start.
The Court of Arbitration for Sport sided with him in 2008. Research led by MIT biomechanist Hugh Herr played a role in that reversal, and the IAAF’s earlier ruling was overturned, clearing Pistorius to chase an Olympic spot. He ultimately competed at the London 2012 Olympics, becoming the first double amputee sprinter to do so, before going on to the Paralympics that same summer.
This is the pattern that recurs across all three disputes examined in this note.
THE OLIVEIRA CALLROOM DECISION
The 2012 London Paralympics produced the more instructive case, precisely because it never got near a court. Pistorius lost the T44 200m final to Brazil’s Alan Oliveira and immediately accused him of exploiting longer blades than his physiology warranted, arguing that the applicable rules allowed athletes to be built up to an artificially estimated height, producing a longer stride than their bodies would naturally support. The International Paralympic Committee (IPC) rejected the complaint the next day, confirming that every athlete in the final had been measured by international classifiers in the call room beforehand and found compliant with the IPC Athletics Classification Handbook.
Legally, this is a call-room decision, not an adjudicated one: there was no hearing, no independent evidentiary record, and no appeal to CAS. The formula IPC pointed to estimates an amputee athlete’s true height from the length of intact body segments, sitting height, upper arm, forearm, thigh, and caps blade length accordingly. World Para Athletics calls this the Maximum Allowable Standing Height (MASH), and it is worth pausing on because it is the actual legal instrument doing the work in every dispute in this note: not a judge’s ruling, not a statute, but an internal regulatory formula that determines, definitively and usually without appeal, who is allowed to compete and at what physical dimensions.2
THE MARKUP REHM CASE: EXCLUSION WITHOUT A RULING
German long jumper Markus Rehm’s case shows how long that kind of unreviewed exclusion can persist. After he won the 2014 German national title, the German Athletics Federation (DLV), not an international tribunal, excluded him from that year’s European Championships, on the view that his blade made his amputated leg three to four centimetres longer than his natural leg. Rehm retained his national title, but the federation’s selection decision was never overturned by CAS or any comparable adjudicatory body; it was a national governing body’s internal judgment call, applied again to keep him out of the Rio 2016 Olympics under a subsequent rule requiring him to prove his prosthesis conferred no advantage. He publicly offered to have all his results annulled if an unfair advantage were ever conclusively proven.
From a legal standpoint, this is a due-process problem as much as a scientific one: an athlete can be excluded from major competition by a domestic federation’s internal assessment, with no adjudicated finding of fact and no clear route to independent review.
THE MASH FORMULA AND ITS ASSUMPTION
The MASH formula itself has now been tested empirically, and found wanting in a way that carries real legal significance. A 2024 study in Scientific Reports examined whether the MASH equations, originally developed using a white Spanish population, hold up across other groups. Applying the equations to nearly 3,000 Black and white American service members, the researchers found that only two of twelve equations validly calculated stature for Black Americans, against three of twelve for white Americans, with bias errors differing systematically between the two groups.3 The study’s authors conclude, in terms, that race and geography affect the validity of the formula that federations apply uniformly to every classified athlete regardless of race or nationality.4
That finding matters legally, not only scientifically. A classification rule that is facially neutral, applied identically to every athlete, can still produce indirect discrimination if it systematically disadvantages athletes from particular ethnic or geographic backgrounds because of the population on which it was calibrated. That is a recognised category of claim in discrimination law generally, and it is precisely the kind of question CAS and national courts have not yet had squarely put to them in this context.
THE SEMENYA PRECEDENT, AND WHY IT APPLIES HERE
The closest legal analogy sport has produced is not a prosthetics case at all, but Caster Semenya’s decade-long challenge to World Athletics’ testosterone regulations. The structural parallel is close: a federation draws an eligibility line based on a physiological measurement, defends it as necessary for fair competition, and an athlete argues the line is scientifically contestable and discriminatory in effect.
Semenya’s case went to CAS, then the Swiss Federal Tribunal, then the European Court of Human Rights. In July 2023, an ECtHR Chamber found that Switzerland had failed to afford Semenya sufficient institutional and procedural safeguards to have her discrimination claims properly examined, given how substantiated and credible those claims were.5 Switzerland sought referral to the Grand Chamber, which delivered judgment in July 2025. The Grand Chamber narrowed the outcome considerably, finding a violation only of the right to a fair hearing under Article 6 of the European Convention on Human Rights, while declaring Semenya’s discrimination and private-life complaints inadmissible for want of a jurisdictional link between her and Switzerland.6 The underlying regulations were never struck down and remain in force.
The net legal lesson for prosthetic classification is narrower than it might first appear, but still real: an international sports body’s internal eligibility formula, once challenged, is only as strong as the procedural rigour behind it, since the tribunal has to actually engage with contested scientific evidence rather than defer to the federation’s own study. Where a prosthetics dispute never reaches CAS at all, as with Oliveira, or is resolved at national-federation level without independent review, as with Rehm, that scrutiny never happens in the first place.
CONCLUSION
None of this makes World Athletics or the IPC bad actors. Regulating a genuinely unresolved biomechanical question is a hard problem, and a sport that does nothing risks the opposite unfairness. But the legal exposure is real and largely untested: a formula with a demonstrated population bias, applied by call-room classifiers with no hearing, producing exclusions that in Rehm’s case lasted over a decade without independent adjudication.
That gap between the athletes who can contest a ruling and the ones who simply live under it will remain the more durable legal problem, more than any single blade length ever was.
Footnotes
1 Pistorius v International Association of Athletics Federations, CAS 2008/A/1480, Award of 16 May 2008.
2 Paralympic Factoid: Blade Runners’ (England Athletics) accessed 20 September 2026.
3 Brian S Baum and Constance Man, ‘Race and Geography Impact Validity of Maximum Allowable Standing Height Equations for Para-Athletes’ (2024) Scientific Reports, DOI: 10.1038/s41598-024-56597-y.
4 ibid.
5 Semenya v Switzerland App. no 10934/21 (ECtHR, 11 July 2023).
6 Semenya v Switzerland App no 10934/21 (ECtHR, Grand Chamber, 10 July 2025).
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