For every sweat-soaked victory on the track at the Olympic Stadium in Tokyo, there were a lot of hopes dashed in a single misstep.
Trips in particular — a sprinter who miscalculated ahead of a hurdle, a runner tangled up in a tight pack — elicited gasps from the few spectators allowed in the stadium.
One of the runners whose Olympic journey ended facedown on the track was Isaiah Jewett, an effervescent 24-year-old from California. He won the 800-meter N.C.A.A. title in June and qualified for his first Olympic Games later that month by running his personal best time and shocking Donavan Brazier in the process.