During the 1960s and 1970s, "traditional" secondary educational systems in various Western European countries made way for comprehensive education curricula. In contrast to the reforms within the "intellectual" subjects, the field of physical education (PE) remained largely underexposed in research. This study focuses on PE reform in Belgium, the first country in the world (apart from Sweden itself) to introduce, in 1908, so-called "Swedish gymnastics" in all levels of state public education and, in 1968, the last country apart from Portugal to abandon it. The question arises as to who was responsible for Swedish gymnastics being applied for so long and, ultimately, how and by whom reform was implemented. The results show that the power of the past and the positions of "Swedists" in the Government Inspectorate, universities and professional associations, perpetuated the domination of Swedish gymnastics in Belgian education. The final "dynamisation" of the subject of PE around 1968 did not come about through "revolution" but a "natural" generational transition, whereby a new guard of young government inspectors with a drive for reform took over from their Swedish-minded predecessors. The educational climate prevailing in Belgium at the end of the 1960s facilitated this reform. The state university PE institutes lost their position as pedagogical profile keepers during this process of transformation, while the hidden curriculum of the (Catholic) university institute in Leuven implicitly shaped the educational climate. Further comparative international research into the (changed) profile, position and power of school inspectors in educational reform appears necessary.