KITTERY, Maine (AP) — Two National Guardsmen from Maine are embarking on a grueling mission — but it isn’t overseas.

Col. Jack Mosher of Waterville and Maj. Herbert Brock of Winslow are running 550 miles from Kittery to Arlington National Cemetery in Virginia. For the trek, they will each run 13.1 miles a day — the equivalent of 21 marathons in 21 days between them.

Their journey begins Saturday. Along the way, the pair will visit veteran’s medical centers to tout the many programs that are available to returning soldiers.

Mosher and Brock say they are making the run to promote the idea that physical fitness builds resiliency for soldiers who are having a tough time after returning home from service overseas.