Markus Rehm wants to represent Germany in Rio this summer. He is the Paralympic champion and jumps off of a prosthetic leg (pictured above). IAAF rules allow prosthetics in only if they are judged to provide no additional benefit to the athlete over an athlete who is not using a prosthetic.
Here is the relevant IAAF rule in full (Rule 144.3 at p. 153 in the IAAF Rules):
German Disabled Sports Association is sponsoring a study to determine whether Rehm does or does not receive a "competitive advantage" through the use the prosthetic. The study is being conducted by the German Sports University Cologne, National Institute of Advanced Industrial Science and Technology/Human Informatics Research Institute in Tokyo and the University of Colorado-Boulder (where I am a professor). The results are expected to be reported in June.
In parallel the IAAF has created an internal Working Group to clarify Rule 144.3 which is "to bring clarity to what is a complex question of technical eligibility as soon as possible so athletes wishing to compete at the European Championships in Amsterdam and at Olympics in Rio are aware of eligibility." This Working Group is expected to report in June. It is unclear if the Group is to consider the just-commissioned study - they do state that they "will draw upon extensive knowledge from across disability and able-bodied athletics."
As we learned in the case of Oscar Pistorius, science does not always speak with one voice. In fact, the science of competitive advantage using prosthetics is like many other areas of science where a range of legitimate views are possible, based on valid assumptions and methods. Perhaps Rehm's case will be more clear cut than Pistoirus' case was - but maybe not. Rehm has already hinted at legal action if he is not allowed to jump in Rio.
Pistorius case was easier in an important respect because he was not a threat to medal in the Olympics. So his participation was framed as a feel-good story, not a story of epic achievement. Rehm is different. He threatens to medal if he is allowed to participate, and maybe even break the world record. That makes the decision to include or exclude him far more significant.
Sport turns to science to answer difficult questions with some risk, because science doesn't always have a single answer. This one may get interesting, stay tuned.