Look what has happened to the 49ers' bell cow. He has become a raging bull. Frank Gore is sticking and moving, bobbing and weaving around the ring, his punches exploding off the trainer's mitts like a string of firecrackers. Ding! Round over. "You hear of fighters who don't have knockout power?" trainer Brian Schwartz asks. "If Frank was a fighter, he'd have knockout power. His punches are fast and snappy." "Explosive!" says Gore, smiling and moving his head in time to this workout's sound track, Michael Jackson's "Thriller." Gore is an old-school old soul. Ding! Back to work. Their ring dance is partly choreographed, partly ad-libbed, 100 percent fierce. Gore reacts to Schwartz's pad cues. React and attack, just like football. "When I see the hole, I go get it," Gore says, clearly enjoying himself. Gore is 31, heading into his 10th season with the 49ers, his ninth as the bell cow, the spiritual leader of the offense. For the past three years, Gore has trained in the offseason at Schwartz's Undisputed Boxing Gym in San Carlos.