Many people believe that completing a marathon in 5 hours needs continuous running. However nothing could possibly be further from the honest truth. Just view rivals near completion of a marathon-- point out, at mile 19 or mile 23-- and you will see many of them walking. Yet that is not the strolling to which I am referring. http://www.selfgrowth.com/articles/just-how-often-do-you-need-to-run-to-train-for-a-half-marathon