 The Cooperative Lifestyle Intervention Program CLIP will test the effects of a physical activity intervention and a weight loss intervention on mobility disability of overweight or obese men and women who have evidence of cardiovascular disease or the metabolic syndrome. The public health relevance of the trial lies in the fact that the interventions will be delivered in conjunction with four Cooperative Extension Centers in counties surrounding Winston-Salem, North Carolina. CLIP will be designed as a three arm, randomized, controlled trial. The three 18-month treatments will include: 1 a basic health education-based control condition, 2 a group treatment program for physical activity, and 3 a lifestyle intervention designed to reduce sedentary behavior and promote weight loss. The primary aim will be to compare the effects of the three treatment arms on the change in performance on a 400-meter walk test over the course of 18 months. Secondary aims will include changes in cardiovascular risk factors, adiposity, cardiovascular fitness, physical activity, and health-related quality of life. Analyses will also be conducted to determine whether changes in the primary outcome are mediated by changes in constructs from social cognitive theory. 