Can Newsround's Leah crack the London Marathon?
On Sunday 22nd April our Leah takes on the 2012 London Marathon.
She'll join 35 thousand runners all hoping to complete the 26.2 mile course.
As the big day looms and the butterflies kick in does she have what it takes to cross the finish line?
Watch Leah being put through her paces in training in this video, then watch this space to see what happens on the big day.