Runners feel shortchanged after Sunday’s Chicago Half Marathon was shortened by a half-mile

Khoa Dao finished a half-marathon Sunday along Chicago’s lakefront feeling elated, crossing the finish line seemingly 15 minutes faster than his previous personal record. He celebrated and took some selfies.

“I felt like king of the world,” he said.

But later in the day, Dao’s enthusiasm was punctured when he learned the 13.1-mile HOKA One One Chicago Half Marathon was actually about 12.6 miles.

Organizers of the race, which started in Jackson Park and attracted thousands of runners, changed the course “just prior to the start of the event” after being directed to do so by the city of Chicago, according to an email sent to runners two days after the race.

In a statement sent to the Tribune, race organizers apologized for the mishap and said they are planning to offer runners discounted entry on a future event of their choice.

“Given the last-minute timing of this change, options were extremely limited to properly inform all event participants prior to the start of the event,” the statement said. “We apologize to all participants for the lack of advance notice of this change.”

The course change angered runners, some of whom had traveled to Chicago to participate. Some had hoped to achieve a personal record, or use the race to qualify for other events. Others had simply aimed to finish their first half-marathon.

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Dao didn’t finish the race quite as fast as he initially thought — but it would have been a personal record if the race was the correct distance.

Runners questioned why the course change wasn’t communicated to them, perhaps via a loudspeaker, and asked why race officials didn’t have a backup plan, or couldn’t implement a half-mile detour. A Facebook post on the event’s page generated hundreds of comments.

“People pay a lot of money … to run these races,” Stephanie Tsai, a Chicago runner who participated in the event, told the Tribune.

The route change was requested to “ensure the safety of race participants due to a conflict with vehicles around 31st Street,” a city spokesperson said in a statement. The issue stemmed from traffic flow around Soldier Field.

While running, Tsai knew something was amiss because the mileage on her GPS watch didn’t match up with the signposts on the course. She had been running on pace for a record.

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Tim Bradley, interim executive director at the Chicago Area Runners Association, said the last-minute move to shorten the course was unusual for such a big race.

“It’s not very common. It’s very unfortunate and disappointing when it does happen,” he said, noting it sometimes happens during smaller races.

Crystal Rosales, like Tsai, thought something was off when her watch mileage didn’t match up with the route. Sometimes during big races, though, GPS tracking doesn’t work as well.

But as soon as she crossed the finish line, she joined groups of other puzzled runners looking at their watches and noting the shortage.

“Everybody was asking the same questions,” she said. “Everyone was kind of wondering what was going on.”

Race organizers later changed the official results to reflect that the race was 12.6 miles.

“I was disappointed,” Rosales said, noting that she has previously run other races. “I was also disappointed for the first-timers … a half-marathon is a huge distance.”

mabuckley@chicagotribune.com