Complex sentence: In the fall of 2003 he ran a personal best of 2:10.13 in the 2003 Fukuoka marathon and competed in the marathon in the 2004 Summer Olympics, but did not finish.
Split into simpler sentences: In the fall of 2003 he ran a personal best of 2:10.13 in the 2003 Fukuoka marathon. He competed in the marathon in the 2004 Summer Olympics, but did not finish.