You could choreograph the entire plot outline of Step Up after hearing only a brief description of the movie’s premise, but the dancing is another matter entirely. This follows the cliched, Romeo-and-Juliet romance between a criminally inclined Baltimore street dancer (Channing Tatum) and a high-strung ballet student (Jenna Dewan), but rather than concentrating on the odd-couple idiosyncrasies it focuses on what all the characters in the movie share: a love of moving to music. Thanks to the enthusiastic eye of director Anne Fletcher, whose first career was as a dancer and choreographer, the picture has a sense of exhilaration that’s infectious.