What is the theme in The Crazy Horse Electric Game by Chris Crutcher?

One of the prevalent themes in the book involves how young people determine their identity as they come of age. For Willie Weaver, he identifies himself as an athlete first and foremost. Because of his talent on the baseball field and the relative ease with which he is able to master certain sports, Willie couldn't image living his life any other way. His accident and subsequent disability challenges his identity.