BOSTON (CBS) — Every step U.S. Army Veteran Master Sergeant (Ret.) Cedric King takes, he knows it’s for a deeper purpose. “Even though I was in a position where I lost my legs, it did not give me an excuse not to keep fighting. I want people in Boston to understand that if I can do this, then they can do any challenge they have in front of them,” he said.

The 42-year-old lost both his legs after stepping on an improvised explosive device while serving in Afghanistan in 2012. Twenty-one months later he completed his first Boston Marathon.

Now he’s back for another 26.2 miles.

“The preparation for this year has been a little tough,” King said.

This will be King’s fifth Boston Marathon and there is no doubt he will finish. He’s done it on his prosthetic legs and in a wheelchair. This time he plans to cross the finish line by hand cycling.

“Finishing it on all three platforms is fantastic and gives me the ability to know that if I can do this on three different platforms — prosthetics, a wheelchair, and hand cycling– then I can do anything,” he said.

When King isn’t training, he gives talks around the country and tells his amazing story of true heroism through the Penfed Credit Union Foundation Speaker’s Bureau.

“Corporations and businesses in this country need to hear the stories coming out of Afghanistan and Iraq,” he said.

King has also written his own book called ‘The Making Point’. He hopes his story will encourage others to keep on fighting.

“I just want someone to have a better today than they had yesterday.”