Gréhaigne and Godbout (1995) posed that a player's cognitive map is “ the declarative and procedural knowledge accumulated through past experiences that influence the player's interpretation of a configuration of play perceived in connection with efficient action rules.” The novice player has limited experience to influence interpretation of play (French & McPherson, 1996). The Tactical Games Model (TGM) is one instructional model which assumes to facilitate students' tactical understanding (Mitchell, Oslin & Griffin, 2006). However, limited research has examined how knowledge structures develop for the novice, using this model. Purpose: This study was a pilot study and examined sixth-grade students' tactical understanding and conceptions of volleyball throughout a TGM unit. Methods: Participants were two physical educators and purposively selected students (n=8; M=4, F=4) from their sixth-grade physical education (PE) class (N=60) at a suburban school, in the northeastern United States. The unit was co-taught (6 X 45 minute classes). Selected students remained in cohort teams participating against each other. The tactical problem of the lesson was setting up to attack and focused on base positioning, several aspects of containing the ball, and selecting the set from a playable ball. Multiple data sources included: 1) pre and post unit student interviews and situational diagramming, 2) descriptive field notes, and 3) a post unit situational knowledge quiz. Analysis/Results: An information processing framework, specifically mental models, was used as a lens for analysis. Interviews were open, axial, and selective coded, then triangulated to develop categories. Categories were constructed into individual profiles for each student. Results are reported as pre-post student metal models. Additionally, data are reported to verify TGM instruction. Results revealed students': 1) “about” game knowledge, 2) “in” game knowledge, and 3) accurate/inaccurate conceptions. Across the unit, low skilled students developed increasingly accurate conceptions and quality conceptions. Higher skilled students initially had accurate concepts and were able to provide more “in” game concepts over time. Conclusions: TGM may facilitate the development of student knowledge structures. Concerns and limitations of this study are discussed in relationship to: 1) unit length, 2) connections to students' prior knowledge and experiences, 3) the use of teacher language to connect the tactical problem and game-set to student game play, and 4) observation of tactics as opposed to sole observation of skill.Keyword(s): curriculum, physical education PK-12, play