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E Glossary Accelerometry In the measurement of physical activity, the use of ac- celerometers (devices that detect and quantify body movement). Fre- quently used as a pedometer to count the number of steps taken throughout the day. Activities of daily living Activities related to personal care that in- clude bathing or showering, dressing, getting in or out of bed or a chair, using the toilet, and eating. Aerobic capacity (power) An indicator of endurance capacity or fit- ness. It is a measure of the body's ability to process oxygen. It involves a combination of lung capacity, the size of the capillaries, the pumping action of the heart, and the transfer of oxygen from red blood cells to target tissues. It is frequently referred to as maximal oxygen uptake or VO2max. Balance A skill-related component of physical fitness that relates to the maintenance of equilibrium while stationary or moving. Body composition A health-related component of physical fitness that relates to the relative amounts of muscle, fat, bone, and other vital parts of the body. Bone mineral content The amount of mineral at a particular skeletal site, such as the femoral neck, lumbar spine, or total body. 195

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196 PHYSICAL ACTIVITY WORKSHOP Bone mineral density Determined by dividing the bone mineral content by the area of a scanned region. Cardiorespiratory endurance A health-related component of physical fitness that relates to the ability of the circulatory and respiratory sys- tems to supply oxygen during sustained physical activity. Also called cardiorespiratory fitness or aerobic capacity. Children Persons ages 2 to 11 years. In this summary, refers mainly to persons ages 6 to 11 years. Disability A physical or mental impairment that substantially limits or restricts the condition, manner, or duration under which an average person in the population can perform a major life activity, such as walking, seeing, hearing, speaking, breathing, learning, working, or taking care of oneself. Duration The length of time spent participating in physical activity (e.g., 30 minutes per occasion). Endurance activities Repetitive, aerobic use of large muscles (e.g., walking, bicycling, swimming). Evidence-informed The accumulation of data from a wide variety of research designs and clinical experiences used to reach a solid con- clusion. Exercise Planned, structured, and repetitive bodly movement done to improve or maintain one or more components of physical fitness. In this summary, the term is used interchangeably with physical activity. Flexibility A health-related component of physical fitness that relates to the range of motion available at a joint. Frequency The number of times spent participating in physical activity over a specified period (e.g., two times per week).

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197 APPENDIX E Intensity A characteristic of a physical activity that represents how "hard" it is performed or perceived by a person. Examples of inten- sity categories of a physical activity are light, moderate, or vigorous. Kilocalorie (kcal) A unit of measurement for energy, either consumed through food and beverages or expended both through physical activ- ity and basal metabolic processes. 1 kilocalorie = 1 calorie = 4,184 joules = 4.184 kilojoules. Metabolic equivalent (MET) A unit used to estimate the metabolic cost (oxygen consumption) of physical activity. One MET equals the resting metabolic rate of approximately 3.5 ml O2 * kg-1 * min-1. Moderate intensity A general descriptor of the physical activity inten- sity that causes some increase in heart rate and breathing rate but at which the person feels comfortable exercising for an extended period of time. A benchmark of moderate-intensity activity for a healthy middle-aged adult would be brisk walking. Muscle fiber An individual muscle cell. Overtraining The attempt to do more work than can be physically tolerated. Period The time span that is covered by a survey or other measurement instrument (e.g., the last week). Physical activity Bodily movement that is produced by the contraction of skeletal muscle and that increases energy expenditure. Physical fitness A set of attributes or conditions that allows an indi- vidual to carry out daily activities without undue fatigue and with sufficient reserve to enjoy leisure pursuits. Physical fitness is as- sessed through many components, including muscular strength and endurance, flexibility, cardiovascular endurance, body composition, agility, balance, and speed. Physical inactivity The state of doing no or very little activity (being sedentary).

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198 PHYSICAL ACTIVITY WORKSHOP Power A skill-related component of physical fitness that relates to the rate at which one can perform work. Resistance training Training designed primarily to increase muscle strength, power, and endurance. Sarcopenia Age-related degenerative decreases in skeletal muscle mass. Strain An injury resulting from overstretching and tearing a muscle. A strain can occur through an accident or through improper use or overuse of a muscle. Strength The ability of the muscle to exert force. Strength of evidence A general indication of how confident one can be that there is a causal relationship between an exposure (e.g., physical activity) and a specific health or fitness outcome. The strength of evidence will be determined by the number, type, and quality of the studies that have been conducted addressing the rela- tionship, the consistency of the results among studies, and the effect size (or magnitude of the relationship). Vigorous intensity A general descriptor of the physical activity inten- sity that causes large increases in heart rate and breathing rate and that causes fatigue within a short period of time. A benchmark of vigorous-intensity activity for a healthy middle-aged adult would be running at 8–10 mph. VO2 The amount of oxygen consumed per minute by an individual while performing an activity. VO2max The maximal capacity for oxygen consumption by the body during maximal exertion. Youth Younger and older adolescents or teens, ages 12 to 19 years. For convenience in this summary, the term youth is often used to re- fer to school-aged children and adolescents.