The dispute erupted into several rounds of clashes last year, killing dozens of people, including soldiers and civilians, and displacing more than a million in July and December.
He said he started doing sport during the Covid pandemic, when he signed up for an Iron Man, a long-distance triathlon, which he saw as the "pinnacle of human capacity."
The International Court of Justice granted Cambodia sovereignty over Preah Vihear in 1962 and over a patch of land surrounding the temple in 2013, but Thailand does not recognise the tribunal's jurisdiction.