Winner Disqualified for Too-Thick Shoes in Vienna Marathon
In the first disqualification under the World Athletic's 2020 shoe ruling, Derara Hurisa was stripped of his victory for wearing shoes with a 50mm midsole height.
45 minutes after crossing the line first at Sunday’s Vienna Marathon, Ethiopia’s Derara Hurisa was disqualified for running in shoes that exceeded the 40mm stack height limit set by World Athletics. It is the first known disqualification due to shoes under the January 31, 2020 ruling.
Winner disqualified: The initial winner of the Vienna City Marathon had to be disqualified for wearing shoes which are not compliant with the rules. Ethiopia’s Derara Hurisa crossed the finish line first after 2:09:22 …
— Vienna City Marathon (@Vienna_Marathon) September 12, 2021
… The sole of road running shoes has to be no thicker than four centimeters. Hurisa was running with a model that has a sole thickness of five centimeters …
— Vienna City Marathon (@Vienna_Marathon) September 12, 2021

Hurisa appears to be wearing the Adidas Adizero Prime X shoe, a model designed to be a training shoe and marketed as “what’s possible when we throw the rule book away.” The model breaks the rules not only with its 50mm-thick midsole — which the Vienna organizers cited — but also with use of multiple layers of carbon fiber plates or blades.
The World Athletics’ regulation states that shoes “…must not contain more than one rigid plate or blade made from carbon fibre or another material with similar properties or producing similar effects” and adds: “The one rigid plate or blade referred to in Rule 5.13.1 may be in more than one part but those parts must be located sequentially, in one plane, not in parallel (i.e., not stacked above each other), and must not overlap.”

Scientist Geoffrey Burns, one of the first to suggest stack height limitations, explains that while a thicker shoe isn’t necessarily faster, it allows for more complexity and more potential for performing-enhancing devices, as well as additional layers of rebounding super foams. How the shoes create their performance-enhancing effects is still somewhat a mystery, and scientists continue to hypothesize and research how the plates, foam and rocker work together with the runner’s stride.
The 40mm limit, while arbitrary, sets a standard to assure a level playing field for all participants while allowing for innovation within the parameters. Stack heights are also relatively easy to verify visually, which appears to have happened in Vienna.
Reports say that Hurisa declared a different adidas model on his pre-race form, but then ran in shoes he had worn in training. Declared shoes must appear on World Athletics’ list of models that meet their criteria.
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