SEDENTARY BEHAVIOR INTERVENTION: APPLICATION OF CONTEXTUAL INFORMATION OF SEDENTARY BEHAVIOR

Abstract

The objective of this dissertation is twofold. First, it aims to validate a self-report, sedentary behavior measure—known as the Sedentary Behavior Record (SBR)—that measures the contextual information of sedentary behavior. Second, it aims to evaluate the feasibility of using the contextual information of sedentary behavior to reduce sedentary behavior time. Regarding the first study, the goal is to validate the SBR against a criterion measure that uses a proxy for direct observation; the proxy here is an Autographer wearable camera. To establish evidence of validity (i.e., classification accuracy), the investigator compared images obtained from the camera with patient-reported sedentary behavior status and activity classification. Researchers calculated the contingency (C) coefficients between the SBR and the Autographer. C coefficients were also compared across domains, types, time of day, and type of day. The findings show that the overall C coefficient between SBR and the Autographer was acceptable (C = .70). The purpose of the second study is to evaluate the feasibility and effectiveness of the tailored domain-specific sedentary behavior intervention. The evaluation, which is done using contextual information of sedentary behavior, is intended to reduce sedentary behavior time among adults. Participants’ sedentary behavior time was measured by accelerometers, and contextual information of their sedentary behavior was obtained from the SBR. The finding highlighted that the tailored domain-specific sedentary behavior intervention decreased sedentary behavior time for the 2-week intervention period. The observed decrease of 74 minutes a day in objectively measured sitting time represented a medium effect size (0.56). Together, these two studies yield insights into the usefulness of contextual information of an individual’s sedentary behavior; they also helped justify the use of contextual information in health research and to come up with interventions to reduce sedentary behavior in physical activity.