Jason Maderer of Georgia Tech investigated the reasons behind faster speeds in Olympic swimming pools. The tl;dr answer is structural engineering and high-quality materials. He looked at Georgia Tech’s McAuley Aquatic Facility, the venue for swimming at the Olympics in Atlanta in 1996.
Everything — air flow, depth, and more — are in place with speed in mind.
“There are three primary reasons why the Georgia Tech pool is still among the fastest, even after a quarter century,” said Jud Ready, an adjunct professor in the School of Materials Science and Engineering who teaches a class about the materials and engineering concepts of sports. “Two are at the bottom of the pool and the other is at the sides.”
Factors include depth, water temperature, a pool’s return jets, and an efficient guttering system:
“Water goes in but doesn’t come back out,” said Ready. “If the gutter system was shallow, it would fill up, bounce water back into the pool, and make the surface choppy. This would create resistance against the swimmers, slowing them down.”