This article has provided an initial description and interpretation of some of the more obscure concepts extant to ecological systems theory. The challenge now is to apply these concepts to a larger teacher pool and, if found reliable, to use them, in the promotion of enhanced instructional effectiveness from preparatory to professional practice activities. In the absence of future pursuit recommendations, what this article also provides with immediacy is support for the view that alternative and increased vocabularies for the description and conveyance of effective educational activity is a warranted and necessary activity. It should be noted, however, that the context for which these constructs are hypothesized is that of "direct instruction." That is, observations of teacher and student behaviors that served to generate the notions of momentum and pacing (as examples) were all taken from lessons in which the instructional focus was teacher directed. What would be of particular interest (and of significant challenge) would be to examine whether the current definitions are valid in other less-directed instructional settings such as cooperative learning, Sport Education, project-based learning, or perhaps teaching for personal and social responsibility. ©2007 Human Kinetics, Inc.