He said his military training kicked in when he dropped to his hands and knees and crawled, at times pulling himself on his stomach, for the final 90m.
"It was kind of second nature," he said today, a day after finishing his third marathon.
"They instill 'adapt and overcome.' Any situation you're in, that's what you do."
During the marathon, Herndon, 31, said he repeated the names of three men — Marines Mark Juarez and Matthew Ballard and British journalist Rupert Hamer — kilometre after kilometre.
Juarez and Hamer were killed when a roadside bomb exploded in January 2010. Ballard, who was severely injured, died after returning home. Herndon was in that convoy, but his vehicle wasn't hit.
Repeating their names is something Herndon does when he's training or competing in a race, even when he gets strange looks from other runners.
Herndon, who was injured in another blast in 2010, got into running after coming home as a way to deal with post-traumatic stress. He hopes he can inspire other veterans.
"It's hard to reintegrate into society and be a civilian," he said.
"My message to other veterans is to find whatever your release is. My release happens to be running."
- AP
