Over the past week, the word “marathon” has become shackled to other words such as “bombing,” “terrorism” and “attack,” and although Metro police and event organizers have promised extra diligence, no doubt those concerns will weigh upon the more than 30,000 participants expected this year in Nashville’s annual run. So there’s no better time for Music City to help remind the world that the term has come to signify the heights of human endeavor and endurance. Any idiot with a lighter and an M-80 can blow things up — mostly thumbs — but can you run or walk 26 miles from Centennial Park to MetroCenter to 12South to the East Bank’s LP Field, as the city’s rolling topography does its best San Francisco imitation? Or can you hang for 13 foot-blistering miles in the half-marathon? For those who can, or even try, prizes await along with T-shirts, medals, goodie bags and admission to the post-race blowout featuring Craig Morgan and Sarah Darling. Registration is $150 or $75 for the half; through Friday you can register at the Nashville Convention Center’s Fitness and Health Expo. For more information, see runrocknroll.competitor.com/nashville.