At a young age, Mark Walker learned he wasn’t like his friends.Born with a heart defect, Walker had an angioplasty at age 4, sidelining him from the athletic field for many of his school years.“I should not, arguably, be alive,” the West Lafayette native said matter-of-factly.But for the past eight years — ever since he won a paid trip to the Iditarod, the famous Alaskan dog sled race — Walker has been getting his athletic fix in an unusual way: Dog mushing.“I’ve run dogs up to 110 miles at a time,” Walker said. “That’s the equivalent of going from Chicago to West Lafayette on a dog team.”Read more here: http://www.jconline.com/article/20130130/NEWS/301300038/West-Lafayette-native-finds-passion-dog-mushing-trains-Iditarod?nclick_check=1