Three US swimming researchers say a current in the Rio pool boosted the speed of swimmers in high-numbered lanes during the Olympic men’s and women’s 50-meter freestyle competitions Aug. 11-13, the Wall Street Journal reported.
The researchers—Joel Stager and Chris Brammer at Indiana University’s Counsilman Center for the Science of Swimming and Eastern Michigan University professor Andrew Cornett—discovered the lane bias by analyzing performance data from the Olympic races.
They found that most of the eight men and eight women who qualified for the 50-meter finals swam in lanes four through eight of the eight-lane pool during the semifinals. And five of the six men and women who medaled in the 50-meter races, with the exception of American Anthony Ervin, swam in those lanes during the finals.
In the 800-meter and 1,500-meter races, the researchers also found evidence that the direction and lanes competitors swam in impacted their times swimming toward and away from the start blocks. It’s unclear whether the lane bias also affected the overall outcome of these races.
The researchers believe the issue is linked to a design flaw in the pool that was built specifically for the Rio games, and to be taken down when they conclude. Biases in swim times tied to lanes and directions, such as those allegedly found in the Olympic races, occur more commonly in temporary pools like the one in Rio, Stager, Brammer, and Cornett showed in another paper published in March, which analysed swim competitions from 2000 to 2013.
The temporary pool used in Rio was reportedly constructed by a company called Myrtha Pools. It’s the same company that built the pool used in the 2013 world swimming championships, which was mired by a comparable current controversy. A 2014 paper by the same authors found lane biases that suggested there was a current was in that pool as well.
At the time, Myrtha Pools agreed that the findings indicated the presence of a current, and told the Wall Street Journal (paywall) “this is just an anomaly we were not prepared for.”
When contacted by the publication this time around, a spokesperson for Myrtha Pools said the company tested the Rio pool and found “no indication whatsoever” of a current.
Myrtha Pools did not immediately respond to Quartz’s request for comment. The International Olympic Committee referred Quartz to the Rio 2016 Organizing Committee for comment. It also did not respond immediately.
The international body that governs swimming, FINA, is reportedly reviewing the analysis.
Based on the analysis reported, it doesn’t seem as though any one country or athlete benefited more than others from the lane bias. The teams were spread out in lanes throughout the pool, and athletes used different lanes in the finals, semifinals, and other heats, the Olympic rosters showed.