Yoo Ji-won, a 25-year-old graduate researcher and running content creator, has died after collapsing about 500 metres from the finish of a half-marathon in Seoul, South Korea. She was taking part in the 2026 Seoul Race on 11 October when she suffered a medical emergency.
Yoo researched artificial intelligence semiconductors at the Korea Advanced Institute of Science and Technology (KAIST) and documented her training and race achievements online. Organisers said the runner received emergency treatment before being taken to a medical facility, where she subsequently died. The cause of her collapse and death has not been publicly disclosed.
