FILE - In this Sunday, July 28, 2019, photo, Shelby Houlihan crosses the finish line as she wins the women's 5,000-meter run at the U.S. Championships athletics meet, in Des Moines, Iowa. Increasingly sensitive instruments designed to detect banned substances have the ability to pick up increasingly miniscule amounts of those substances in an athlete’s system. In some cases, athletes ingest them intentionally. But in a growing number of instances, the banned drugs enter their systems in completely unintentional ways. (AP Photo/Charlie Neibergall, File)

FILE - An athlete trains before the World Athletics Championships, Thursday, July 14, 2022, in Eugene, Ore. Shortly after last year’s Olympics, the urine samples of some six dozen athletes came back with traces of a banned stimulant. Career-altering penalties loomed. But they were avoided thanks to some nimble sleuthing by anti-doping scientists in the U.S. and Germany. The scientists discovered the stimulant could be found in an ingredient present in an over-the-counter sunscreen. (AP Photo/Gregory Bull, File)

FILE - Jessica Calalang and Brian Johnson compete in the pairs free skate program during the U.S. Figure Skating Championships Saturday, Jan. 8, 2022, in Nashville, Tenn. Increasingly sensitive instruments designed to detect banned substances have the ability to pick up increasingly miniscule amounts of those substances in an athlete’s system. In some cases, athletes ingest them intentionally. But in a growing number of instances, the banned drugs enter their systems in completely unintentional ways. Calalang's positive test cost her eight months of legal wrangling and a spot at world championships in 2021. (AP Photo/Mark Zaleski, File)