Objective   To examine the exercise behavior of adolescents; to reveal the differences in self-efficacy and decision balance by the stages of exercise behavior, and to identify the relationship between exercise behavior and psychological variables.

  Methods   A total of 1 192 adolescents randomly selected from junior high and senior high schools were surveyed.Three questionnaires were used to identify the stage of exercise behavior and psychological attributes of adolescents: Stage of Exercise Behavior Change Questionnaire, Decision Balance Scale for Exercise, and Exercise Self-efficacy Scale.

  Results   The exercise pattern of adolescents was different by each stage of exercise behavior: precontemplation(21.7%), contemplation (24.9%), preparation(37.4%), action(6.1%), and maintenance(9.8%).Significant differencesin exercise behavior distribution emerged as a function of gender and.In addition, exercise self-efficacy, exercise benefits and exercise barriers differentiated across the stages of exercise behavior.Furthermore, the findings revealed that the selected psychological variables had a significant impact on the exercise behavior.

  Conclusion   The findings obtained form the research imply that development of health education aimed at adolescents exercise behavior should be stage-matched.