The two Boulderites should contend for the win on Sunday.
Americans Tyler McCandless, Fernando Cabada, Stephanie Rothstein Bruce and Maegan Krifchin amongst top entrants.
30-year-old American is in the midst of a comeback, and he hopes his hard work pays off in Boston.
We caught up with the surprise second American finisher at last Sunday's Houston Marathon.
There's plenty to be excited about this year as the depth of U.S. distance running is on the rise.
A huge bonus is up for grabs in the half marathon.
Peter Magill, 51 years old, runs 1:10:19 to finish fourth overall at Rock 'n' Roll L.A.
The 30-year-old from Fresno headlines this weekend's Rock 'n' Roll Los Angeles Half Marathon.
American Fernando Cabada took second.
The NCAA 10,000m-record holder will try his hand at 13.1 miles.