Background: Content knowledge is universally acknowledged as one of several knowledge bases that inform pedagogical content knowledge (PCK). Content knowledge has been both hypothesized and demonstrated to influence PCK in two ways. First, teachers must know the rules, safety, etiquette, technique, and tactics of a movement form to teach it. This domain of content knowledge is called common content knowledge (CCK), that is the knowledge that one needs to perform the content. Second, in addition teachers must also know how to select, design, and represent instructional tasks that describe the rules, safety, etiquette, techniques, and tactics to students in ways that they will understand and respond to errors by students in terms of rules, safety, etiquette, techniques, and tactics, that is called specialized content knowledge (SCK) for physical education.