Noah Lyles's narrow victory in the 100 meters would have resulted in a tie if it were a swimming race.

Why don’t Olympic swimming officials use thousandths of a second to break ties? It’s a question of math and science.

PARIS — In the frenzy following the incredibly close men’s 100 meters final at the Stade de France on Sunday night—where American Noah Lyles, Jamaican Kishane Thompson, and nearly 80,000 spectators waited for the final result—the most advanced timing system in sports sprang into action.

As everyone awaited a result that was imperceptible to the naked eye or even initial television replay, on-site judges analyzed timing devices capable of recording to the smallest fractions of a second and reviewed images from three high-speed cameras that captured each race at 40,000 frames per second.

Ultimately, it was determined that although both sprinters had recorded identical times of 9.79 seconds in the standard track measurement, Lyles had actually won the race—and the gold medal—by a slim margin of five-thousandths of a second, with times of 9.784 to 9.789. (According to the rules, times are rounded up.) The entire review process took nearly three times as long as the race itself.

Meanwhile, any swimmer watching on television in the Olympic Village or elsewhere around town would have quickly grasped a key difference between the two sports:

In swimming, that would have been considered a tie for gold.

The difference in how the two sports determine their closest finishes is less a deliberate choice and more a matter of science and mathematics.

In most land-based sports, competitors cross a laser beam at the finish line to record their times. According to Omega Timing, the official timekeeper of the Olympics, this system can measure times to the millionth of a second. While track times are typically recorded to the hundredths of a second, officials will use thousandths of a second to resolve ties.

“Metrology is a precise and definitive science,” said Sebastian Coe, president of World Athletics, the international governing body for track and field. “And you need to ensure that you utilize that technology when you have it.”

In swimming, competitors stop the clock by pressing a touch pad at the ends of their lanes. If two swimmers touch the pad simultaneously, even the most advanced cameras struggle to determine the exact moment each swimmer's touch activated the sensor. While technology can measure times to the thousandths of a second, swimming times are only recorded to the hundredths of a second.

Mike Unger, former chief operating officer of USA Swimming and now a senior adviser for World Aquatics, the sport’s international governing body, explained, “In a pool with water as the medium, achieving such precise measurements is extremely challenging. The technology can handle it, but in a swimming race, a track race at 100 meters would have ended in a tie.”

Unger added, “Going beyond the hundredths of a second is problematic because it’s an imprecise science.”

The discrepancy arises from the inherent differences between the sports and their respective facilities. Unlike track races, which use lasers to precisely measure the finish line, swimming pool engineers and architects strive to construct pools as close to 50 meters in length as possible. They aim for a pool shell length of 50.02 meters, with the touchpads adding an extra two centimeters.