Background: Lack of content knowledge (CK) is problematic in teaching in classroom subject areas and in physical education. There is a dearth of data-based research on interventions aimed at helping teachers acquire CK and, in turn, on the effects of CK on student learning. Aim: To investigate the effect of professional development, in the form of…

This paper describes how improving a teacher's content knowledge changes his teaching practices and its subsequent effects on student learning during a middle school volleyball instructional unit. The study was designed to challenge teacher educators' thinking about the importance of in-depth content knowledge for effective teaching by…