Physical activity has been demonstrated in the literature as an effective way to reduce the risk for development of chronic disease. The Transtheoretical Model (TTM) of behavior change has been developed as a means to predict and facilitate movement into healthier lifestyle behaviors. The model is centered on "stages of change", which describe a continuum of readiness to engage in a health behavior change. Stages contain temporal, qualitative, and quantitative characteristics. This was a six-month study that evaluated the effectiveness of stage-matched (theorized to be pertaining only to the maintenance stage of change) vs. generic (theorized to be pertaining to anyone, regardless of stage) newsletters in assisting subjects to attain the Maintenance stage of change. It also sought to identify further qualitative characteristics that can differentiate between the Action and Maintenance stages of change. Results indicated that monthly stage-matched newsletters were no more effective in helping subjects reaching Maintenance than were the generic newsletters. Exerciser self-schema was related to stages of change, but those relationships differed from baseline to six-month follow-up, indicating development of exerciser self-schema during the study period. Implications of this are discussed. Other concepts discussed included "structure" of change process, in that three new scores were developed …