courage physically inactive children to become active and encourage active children to remain active as they become adults.In response to this challenge, the objectives of determinants and intervention research have been to identify both facilitators and barriers to physical activity and then develop and implement effective programs to increase activity. In this chapter, we focus on physical activity levels, determinants of activity levels, and potential interventions with youth. Our primary focus is on individuals from 10 to 19 years of age. We devote one part of the chapter to the role of health care professionals in promoting physical activity among youth. Throughout, we identify the knowledge and information available that specifically pertains to ethnic minority youth.
Levels of Physical Activity Among YouthThe distinctions among physical activity, exercise, and physical fitness are important because studies in each of these areas focus on different concepts. In their 1985 study, Caspersen, Powell, and Christenson defined physical activity as bodily movement produced by skeletal muscles that results in energy expenditure above the resting level. According to these researchers, exercise is a subset of physical activity associated with higher levels of intensity and exertion; that is, exercise is planned, structured, and repetitive bodily movement to improve or maintain physical fitness. Alternatively, physical fitness is a set of attributes that a person has that influences his or her ability to perform physical activity. Such attributes or fitness components include agility, balance, body composition, cardiorespiratory endurance, flexibility, muscular endurance, muscular strength, and anaerobic power (Baranowski et al., 1992). Individually and combined, these three major components enhance or impede one's capacity to perform activities, to exercise, to participate in sports, or to accomplish occupational tasks. Overall then, physical activity is movement, exercise is a specific type of activity, and fitness is the ability to perform activity.Physical activity includes recreational and leisure-time interests as well as sport involvement. The high end of the physical activity spectrum is vigorous activity, such as running. The low end of the activityCopyright American Psychological Association. Not for further distribution.
INCREASING PHYSICAL ACTIVITY 109spectrum is inactivity or sedentary behaviors, such as television viewing. In addition, physical activity can vary in frequency, intensity, duration, and type. Approaches to measuring physical activity include self-reports (e.g., frequency questionnaires and diaries) and objective assessments (e.g., motion sensors, heart rate monitors, and observation). In population-based studies, objective assessments are typically not financially practical or easy to administer. Recent reviews (Baranowski et al., 1992;Pate, Long, & Heath, 1994;Sallis & McKenzie, 1991) of physical activity levels among youth have included studies using both self-report and objective methods...