Believe that you can run farther or faster. Believe that you're young enough, old enough, strong enough, and so on to accomplish everything you want to do. Don't let worn-out beliefs stop you from moving beyond yourself.
Running is a big question mark that's there each and every day. It asks you, 'Are you going to be a wimp or are you going to be strong today?
Brazen it out! Throw away the scabbard! Grit your teeth, buckle down, and die with your boots on! Or in other words... Be determined and resolved until you accomplish the thing you set out to accomplish.
Persistence wears down resistance.