Skyscraper runners take workouts to incredible heights Sprinting up 86 flights of stairs of the Empire State Building -- even if it's for a worthy cause -- is not everyone's idea of a good time. Especially when there's an elevator nearby. But tonight, more than 650 participants will take the long way up one of New York's most iconic landmarks at this year's Empire State Building Run-Up. It's the 35th annual running of this grueling 1,576-step vertical climb from the ground floor to the Observation Deck. The event features some of the world's top athletes in an emerging sport known as skyscraper running, tower running, or competitive stair climbing. Held in some of the world's tallest buildings -- like Taiwan's Taipei 101, Chicago's Willis Tower and the Menara Tower in Kuala Lumpur, Malaysia -- participants run stairwells against the clock. In case you're curious, Towerrunning holds extensive information on many upcoming national and international races. Last year's male winner from Germany, Thomas Dold, dashed up the 86 stories in a little more than 10 minutes; an Australian named Alice McNamara won the woman's race in just over 13 minutes. Likely to be in the front pack of females this year is Cindy Harris, an Indianapolis accountant who has finished among the top three women for the last 13 years. Harris has won the women's race four times with a personal best of 12 minutes, 45 seconds. She's hoping to come in under 13 minutes this year. A recreational runner, Harris says her running buddies talked her into trying a stair climbing event in Indiana more than a decade ago. Once she completed that, they convinced her to give the Empire State Building Run-Up a shot. Courtesy of New York Road Runners Cindy Harris, a four-time winner of the Empire State Building Run-Up, rounds the 20th floor during the 86-floor climb in 2008. Harris finished second among females that year. Haris was the top-placing female in the race in 1998, 2000, 2001 and 2003. The 43-year-old has been doing it ever since with four first-place trophy replicas of the landmark building to show for her efforts. To prepare, Harris trains in the stairwells of 15-story and 30-story office buildings twice a week. In addition, she keeps up her cardiovascular stamina by running, mostly in 5K up to half-marathon distances, and also works in some Pilates to keep her core muscles strong. As for technique, Harris tends to take the stairs two or three at a time, and she uses her arms on the railings to lessen the load on her legs. At 5-foot-2, she lacks long legs, but a big part of stair climbing is the mental toughness needed to push past the pain and exhaustion. "It's pretty intense and you're breathing hard for almost the entire time," admits Harris. Your legs get heavy and you feel it in your quads. For top competitors like Harris, a stair-climbing race is a roughly comparable workout to a fast-time in a middle-distance run, like a 5K (or 3.1 mile run), says Dr. Joseph Ihm, a physiatrist at the Rehabilitation Institute of Chicago's Spine & Sports Rehabiliation Centers, which hosts the yearly SkyRise Chicago at the Willis Tower. Once called the Sears Tower, this 103-floor, 2109-step climb occurs every November. When stair climbing, the main muscles used for power are in the lower body -- the glutes, hamstrings, quads, and calves, Ihm explains, with arm muscles playing a much smaller role to propel athlete's vertically. Pacing yourself is key, whether you're a top competitor or first-timer. Top stair climbers are moving at a pretty good clip, so they're very winded at the end of the event, similar to what you'd see in middle-distance runners, says Ihm. "When I'm done, it feels like a runner's high," says Harris. But when she's back home in Indianapolis, her coworkers might tease her if they catch her taking the elevator up to her 11th floor office. Have you tried competitive stair climbing? Would you? Tell us about your strangest, most strenuous workouts on Facebook. More fitness stories: