Establishing and Maintaining Physical Exercise

Abstract

Physical exercise can be defined as any goal-directed activity that is intended to improve or maintain physical fitness, and which involves the movement of skeletal muscles resulting in energy expenditure (Caspersen, Powell, & Christenson, 1985). This definition is important because it establishes the goal-directed nature of physical exercise, which distinguishes it from physical activity. For example, in reading this chapter, a number of physical activity behaviors will be performed (e.g., turning pages, shifting positions, walking to retrieve refreshments). However, these behaviors are not intended to promote or maintain health and therefore do not constitute physical exercise. Despite the importance of this distinction, it is difficult for researchers to objectively measure bouts of physical exercise, and gross measures of physical activity are usually used as a proxy indicator. Because this chapter is focused on physical exercise promotion, we will discuss findings in terms of physical exercise even when the primary studies used physical activity as an outcome variable.