Associated Press: Jim Richards is no kid, but he loves to ride his bike. At 51, he has become a cycling commuter, pedaling 11 miles from his home in the suburbs to his job in downtown Knoxville. “It really doesn’t take that much longer” than driving, he insists. And he gets 40 minutes of exercise twice a day without going to the gym, which he attributes to a 20-pound weight loss. New research illustrates the health benefits of regular biking, walking or taking public transportation …