The purpose of this study was to examine the effectiveness of a strategy focused on the development of teaching materials in teaching trials conducted as part of the “Seminar in Methods of Teaching Physical Education” course. In the academic year 2012, such teaching trials were designed to promote the course participants' awareness of “teaching materials” and “subject matter”. As a means of promoting such awareness, participants were assigned new tasks to develop supplementary teaching materials. The reactions of the participants to the trial teaching sessions in 2012 were analyzed and compared with those for 2011. The main findings were as follows: 1) Many of the participants' reactions centered on the fact that the “teaching materials” employed in the first trial did not lead to an improvement in teaching technique. 2) The participants' reactions tended to focus on 2 aspects: “the appropriateness of teaching materials as subject matter” and “the systematic connection of supplementary teaching materials as unit teaching materials”. These results indicated that the strategy used in this study to develop supplementary teaching materials and video observations of the trial teaching sessions were effective for making participants aware of the concepts of “teaching materials” and “subject matter” and the relationship between the 2 from the earlier period of the course.