The researchers hypothesized that adopting higher levels of exercise duration and/or intensity, coupled with a strong behavioral intervention would enhance long-term weight loss. To test this hypothesis, they recruited 200 overweight women and randomly assigned them to one of four treatment groups: (1) moderate intensity, moderate 1000cal/wk duration exercise, (2) vigorous intensity moderate duration exercise, (3) moderate 2000cal/wk intensity, high duration exercise, and (4) vigorous intensity, high duration exercise. All subjects participated in a 24-month behavioral weight loss program, with subjects attending group meetings and receiving periodic telephone contacts from the weight loss program, with subjects attending group meetings and receiving periodic telephone contacts from the interventionists. In addition, to facilitate the adoption of the exercise protocols, all subjects were provided with a home treadmill. Assessment of body weight occured at 0, 6, 12, and 24 months and exercise participation was measured throughout the program. In addition, body composition, cardiorespiratory fitness, cardiovascular disease risk factors, and mediators of behavior change were measured at 0, 6, 12, and 24 months.