PHOTO (News & Observer): Millbrook High wide receiver Nathan Leacock influenced by his parents' college track careers. Visit my website homepage, TomShanahan.Report By TOM SHANAHAN Imagine the ideal track and field athlete. He or she combines a sprinter’s fast-twitch muscles with a middle-distance runner’s aerobic endurance. Explosion and endurance — a potent brew. Millbrook High alumnus Dillon Leacock, a sophomore on the University of Houston track team, inherited the magical combination from his parents. Dillon’s explosion and endurance…