Batman is the most down-to-earth of all the superheroes. He has no special powers from being born on a distant world or bitten by a radioactive spider. All that protects him from the Joker and other Gotham City villains are his wits and a physique shaped by years of trainingâ€”combined with the vast fortune to reach his maximum potential and augment himself with Batmobiles, Batcables and other Bat-goodies, of course. In the 2005 blockbuster Batman Begins, vengeful Bruce Wayne (played by Christian Bale) hones his killer instincts in the streets for seven years before landing himself in a Bhutanese prison, where he falls in with the mysterious League of Shadows, who teach him the way of the ninja. The Dark Knight, the next movie in the Batman franchise, opens in theaters Friday. To investigate whether someone like Bruce Wayne could physically transform himself into a one-man wrecking crew, ScientificAmerican.com turned to E. Paul Zehr, associate professor of kinesiology and neuroscience at the University of Victoria in British Columbia and a 26-year practitioner of Chito-Ryu karate-do. Zehr’s book, Becoming Batman: The Possibility of a Superhero (The Johns Hopkins University Press), due out in October, tackles our very question. An edited transcript of the conversation follows.