The 17-year-old runner suddenly fell at a distance of nearly 100 metres. After collapsing, he was seen crying.
Soraoat 'Ta' Dapbang, a teammate on Puripol, hurried to take care of him.
Thai reporters in the field reported that he may have a hamstring injury, adding that it is uncertain whether Puripol will be able to compete in the 4x100-metre relay and the 100-metre event.