Discourse analyses of science teaching have revealed patterns of knowledge structures (KS) reflecting Halliday's observation that science teaching involves constructing technical taxonomies and relating them in logical sequences. In science education, this pattern has included problem solving as a way for teachers to assess learning. Science has always been considered an academic subject, but how does it compare to physical education (PE)? Given that language is the primary means through which we learn and assess learning, we present a discourse analysis of a sixth-grade PE class taught using a Teaching Games for Understanding (TGfU) approach and compare the discourse to analyses of science teaching. Findings suggest that in the discourse of both PE and science classes, the six KS identified by Mohan as comprising a framework for activities (KF) appear in similar patterns. This focus on similarities rather than differences across diverse disciplinary fields has major implications for educators.