It is commonly accepted that inquiry in adapted physical activity involves the use of different disciplines to address questions. It is often advanced today that complex problems of the kind frequently encountered in adapted physical activity require a combination of disciplines for their solution. At the present time, individual research questions in adapted physical activity are most often developed and pursued by researchers from a single discipline despite incentives to the contrary. However, the inclusion of multiple disciplines to address research questions raises a number of challenges. A major one is effective communication. The language related to the use of multiple disciplines is often used loosely. Key terms, such as multi-disciplinary, interdisciplinary, transdisciplinary, and cross-disciplinary, are often used interchangeably. We introduce the technical meaning of these terms and outline some key epistemic challenges to communication across disciplines and highlight the importance of willingness, on the part of researchers, to carefully listen to each other.