Developing Players' Tactical Knowledge Using Combined Constraints-Led and Step-Game Approaches-A Longitudinal Action-Research Study.

: Using an action-research design, this study examined the impact of combining concepts from two contemporary pedagogical approaches, the Constraints-led Approach (CLA) and Step-Game Approach (SGA), on the development of youth volleyballers' tactical knowledge, as expressed in performance, throughout a full competitive season. : Fifteen players and one coach participated in this study, which involved three action-research cycles, each including the processes of planning, acting and monitoring, reflecting, and fact-finding. The first author, who had the role of coach-researcher, collected data using a reflexive diary and field notes between September 2017 and June 2018, as well as eight semi-structured focus-group interviews. Data were analyzed using thematic analysis, in which inductive procedures deepened understanding of the development of the participants' tactical knowledge. : Findings suggested that combining CLA with SGA improved tactical knowledge in specific ways. Players progressed from a starting point where they were only able to describe game scenarios, and act without tactical criteria or considering contextual game constraints, to a point where their intentions during tactical actions were shaped by their ability to think strategically and guide their attention to recognize and interpret different constraints. : Results suggested that the development of players' tactical knowledge benefited from a mutual integration of different, yet complementary, pedagogical approaches. By integrating SGA and CLA it was possible to enhance players' adaptable thinking using learning tasks involving the manipulation of meaningful constraints that afforded variable repetition and the resolution of tactical problems.