This paper discusses various issues related to the fragmentation and specialization debate by attempting to identify critical factors that have contributed to the present knowledge structure of physical education. Two major factors are considered in depth: (a) lack of a clearly defined knowledge structure, and (b) vertical development of independent subdisciplines that have been guided and dominated by the parent disciplines. The first involves conceptual identification and agreement about subject matter, while the second involves the proliferation of independent specialties, each striving for academic respectability. After careful consideration of the issues, fragmentation is viewed as the underlying problem, and a horizontal cross-disciplinary approach is suggested as a possible solution.