The 39-year-old from Great Britain ran in two Olympic Games.
She's trying to right some wrongs from past games.
Martin Mathathi broke a six-year-old course record.
She's been sidelined for ten months.
She had recently defeated Paula Radcliffe in the Bupa London 10,000m.
She is recovering from a hamstring injury and wants to be near her family.
Only Radcliffe has run faster than Keitany in London.
A hamstring injury sidelines one of Great Britain's fastest marathoners.
The British marathoner thinks her best days are still ahead of her. Mara Yamauchi was one of the top contenders for the win at the ING
Shalane Flanagan finishes second in her marathon debut.