In 1990, a study was conducted to investigate the relationship between students' locus of control and the extent to which they participated in a voluntary exercise program. First-time participants in the "Shape Up" program offered at the Porterville College Fitness Center during the summer and fall semesters of 1990 were identified through the registrar's office. Subjects then completed the 30-item Rotter Internal-External Locus of Control questionnaire on-site. After the subjects participated at their own discretion in the exercise program for the entire term, their attendance records were statistically evaluated. A pilot study of nine attendees, completed during the summer session, provided preliminary results suggesting that there were differences in workout attendance between individuals who perceived their lives to be internally controlled and those who saw themselves as externally controlled. In the study conducted during the fall semester, 23 students participated. Findings of the study indicated that both female and male subjects who perceived themselves to be internally controlled obtained significantly higher attendance scores than those perceiving themselves as more externally controlled. The study concluded that although the locus of control construct served as a discriminative factor with respect to exercise adherence, it was only one aspect of a global motivational system. (JMC)