Complex sentence: Chelimo ran a personal best 13:19.54 in the prelim of the 5000 metres at the 2016 Summer Olympics and initially won the silver medal in the 5000m race.
Split into simpler sentences: Chelimo ran a personal best 13:19.54 in the prelim of the 5000 metres at the 2016 Summer Olympics. He initially won the silver medal in the 5000m race.