For four years, Yoo Ji-won chased finish lines, getting faster at catching them. Between her graduate research in AI semiconductors at KAIST, she trained her way to a sub-three-hour marathon in March and then a category win in a 10K weeks later, sharing the journey with her online followers. On October 11, she lined up for another half-marathon through the heart of Seoul, a distance she had raced before. But 500 metres from the end, the one finish line she was chasing that morning slipped out of reach.

The incident occurred at approximately 8:49 a.m. local time, when Yoo reached the 20.6-kilometre mark of the 21.1-kilometre course. With only around 500 metres remaining, she suddenly lost consciousness and fell. According to the Seoul Metropolitan Government and reports from South Korean media, a race official who found her near Gwancheol-dong in Seoul’s Jongno District immediately called emergency services and performed CPR.

Medical personnel provided emergency treatment before she was transported by ambulance to a nearby hospital. Despite efforts to save her, she later died. The Seoul Race organising committee subsequently confirmed the death and expressed its condolences to her family on October 12.

“We pray for the repose of the deceased and extend our deepest sympathy to the bereaved family facing this sudden sorrow,” the committee stated. It also pledged to review the circumstances surrounding the incident, adding: “We will carefully examine this incident and proceed with necessary follow-up measures without fail.” The exact cause of Yoo’s death has not been publicly confirmed.

News of her death prompted an outpouring of grief from fellow runners, friends and followers. One of the most emotional tributes came from Bummy, a fellow running content creator who shared his experience of learning about the incident. In an Instagram post, he recalled seeing a crowd gather near the finish line and initially thinking that someone had been injured.

“Near the finish line of the Seoul Race, I saw a crowd gathering and thought someone must have been hurt,” Bummy wrote in an Instagram tribute. He explained that after crossing the finish line, he went to look for Yoo at the awards podium but soon received the devastating news. He then rushed to the hospital, hoping for the chance to see her one last time. “I am so sorry I couldn’t stay by your side until the very end,” he wrote.

Yoo’s final reported Instagram update was shared on October 4, a week before the half-marathon, and featured her result from a 10-kilometre run. For someone who had started running just a few years ago and made so much progress, her sudden death is a heartbreaking setback.

Olympic Champion warns runners after Yoo Ji-won’s death

Yoo Ji-won began running in 2022 and quickly became a strong amateur distance runner in South Korea. According to South Korean media reports, Yoo became more focused on improving her race times in the summer of 2025. Despite her demanding academic schedule, she maintained a disciplined training routine, arriving at the laboratory at around 9 a.m. before heading out for approximately two hours of running from 8 p.m. On some evenings, she returned to the laboratory afterwards to continue her research.

Her performances in 2026 showed how far she had progressed in just a few years. On March 15, she completed the full Seoul Marathon in 2 hours, 56 minutes and 32 seconds, breaking the three-hour barrier, a notable achievement for an amateur marathon runner.

Just three weeks later, on April 5, Yoo claimed another major result by winning the women’s masters 10-kilometre category at the 2026 Gunsan Saemangeum Marathon. And the Seoul Race half-marathon on October 11 was her final reported race.

Yoo’s death also prompted a warning from Hwang Young-jo, the South Korean marathon runner who won Olympic gold at the 1992 Barcelona Games. On October 13, Hwang published a video discussing why serious incidents occur during marathon events. 

“People run to live long and healthy lives,” Hwang said, urging participants to consider their physical condition before taking part in races. “Ordinary people don’t get enough sleep, they have stress at work, and sometimes they enter races without having trained properly.”

“There are probably many who run just to show off on social media. When you push yourself recklessly for display rather than for health, that’s when fatal problems arise.” Hwang warned that constantly chasing faster times could lead runners to ignore their limits. 

Until the committee’s review says more, one thing is certain: how little distance remained, about 500 metres, for a runner who had spent years proving she could cover far more. Hwang’s warning speaks to everyone on that course, but it is a caution rather than an explanation, and her family and followers are still waiting for the answer.