Part III of our explainer of California's new favorite sporting event. Read Part II here, and Part I here. Q. In your installment about Tuesday's stage victor, Norseman Thor Hushovd, you said bike racing's low-impact training meant fewer injuries and greater athleticism. So is cycling a sportsman's Valhalla?A. It's not. Unless you believe Odin rules a place where Einherjar are always on the verge of sickness, walk with great pain, live in constant risk of calamitous trauma, lurch from unhealt