Recent studies focus on Metabolic Equivalent Task (MET) to measure levels of and areas of peoples’ physically active lifestyle because MET more readily translate peoples ’subjectively perceived physicality into standardized scores. MET also allows researchers to clearly understand the relationships between peoples’ physicality and psychological variables. Thus, the purpose of this study was to understand the levels of and areas of MET among Korean middle school students and to analyze the relationships between MET scores and physical self-efficacy. A total of 278 questionnaires were analyzed using SPSS 18.0. Exploratory factor analysis, descriptive analyses, and regression analyses indicated that middle school students’ physically active lifestyle occurred in the order school, leisure, housework, and transportation areas. Female students did more physical activity in the areas of housework and transportation, compared to male students. In contrary, male students did the majority of physical activity in the areas of school and leisure. Physical self-efficacy affected students’ MET scores, especially for vigorous intensity activity. With regard to gender differences, physical self-efficacy affected male students’ MET scores in the area of leisure while female students’ MET scores were affected in the areas of school and housework. The results were discussed in light of methodological and pedagogical perspectives, and future research suggestions were provided in the discussion.
