His friends used to call him Hoss, as in Hoss Cartwright from the TV show Bonanza. At 62 and roughly 380 pounds, Mark Rucker once resembled the big, friendly character. Now, they call him The Beast. The nickname is apt. Since February 2011, Rucker has run his first 5K, his first 10K, his first half-marathon and his first marathon. He's completed an Olympic-distance triathlon and lost more than 100 pounds. And on August 26, he 'll participate in his first full-length Ironman competition in Louisville, Kentucky. Like they say, he's a beast. What he does after this Ironman, I do n't know, his wife, Annita Rucker, said with a laugh. I hope he can find something to focus all this energy on. From Rucker's DailyMile blog: April 18, 2011 -- First day of the Couch to 5K program. That was not good. But at least I did the whole workout -LRB- 1.98 miles / 32 minutes / 16:10 pace -RRB- Change is a funny thing, Rucker says. Often, the desire to change grows over time. A series of events leads to an a ha moment, when desire must meet with the proper tools and the right inspiration. In the summer of 2010, Rucker, of Lexington, Kentucky, and his family went to Dollywood in Tennessee. His daughter was 11 at the time, a little daredevil, and wanted to ride all the roller coasters. Unfortunately, Rucker could n't fit on any of them with her. She was devastated; I was crushed, Rucker said. But