Increasing physical activity and, consequently, increasing energy expenditure and reducing obesity are among the highest public health priorities in the U.S. because physical inactivity negatively affects a wide variety of medical conditions (e.g., metabolic syndromes, cardiovascular disease). Research has shown that a major contributor to physical inactivity is the sedentary behavior induced by increased use of computer and video games. However, some of the newer generations of game consoles such as the Nintendo Wii market their product for its physical activity promoting features. Nintendo's recent release of Wii Fit / Wii Fit Plus uses a balance board and is the first game in which whole-body movements closely mirror that of the actual activity. As the use of these gaming systems may be more enjoyable modes of promoting physical activity than the traditional treadmill exercise, respondents may in turn exercise more regularly and for longer periods of time. To the best of the investigators' knowledge, no studies exist that demonstrate the energy expenditure of the Wii Fit / Wii Fit Plus among adults, or the Wii Fit / Wii Fit Plus compared to other forms of aerobic exercise such as walking and running. This study will provide preliminary data for future external grant applications comparing the energy expenditure of different physical activity conditions employing cutting-edge interactive physical activity promoting technology among adults. The potential contributions of the Wii Fit / Wii Fit Plus to promote healthy behaviors by being an alternative form of physical activity may be particularly informative for people who are unable to meet the national public health recommendations due to personal, health, safety or environmental concerns.