James F. Sallis

Compendium of physical activities: classification of energy costs of human physical activities.

A coding scheme is presented for classifying physical activity by rate of energy expenditure, i.e., by intensity. Energy cost was established by a review of published and unpublished data. This coding scheme employs five digits that classify activity by purpose (i.e., sports, occupation, self-care), the specific type of activity, and its intensity as the ratio of work metabolic rate to resting metabolic rate (METs). Energy expenditure in kilocalories or kilocalories per kilogram body weight can be estimated for all activities, specific activities, or activity types. General use of this coding system would enhance the comparability of results across studies using self reports of physical activity.

AHA Guidelines for Primary Prevention of Cardiovascular Disease and Stroke: 2002 Update Consensus Panel Guide to Comprehensive Risk Reduction for Adult Patients Without Coronary or Other Atherosclerotic Vascular Diseases

The initial Guide to the Primary Prevention of Cardiovascular Diseases was published in 1997 as an aid to healthcare professionals and their patients without established coronary artery disease or other atherosclerotic diseases.1 It was intended to complement the American Heart Association (AHA)/American College of Cardiology (ACC) Guidelines for Preventing Heart Attack and Death in Patients with Atherosclerotic Cardiovascular Disease (updated2) and to provide the healthcare professional with a comprehensive approach to patients across a wide spectrum of risk. The imperative to prevent the first episode of coronary disease or stroke or the development of aortic aneurysm and peripheral arterial disease remains as strong as ever because of the still-high rate of first events that are fatal or disabling or require expensive intensive medical care. The evidence that most cardiovascular disease is preventable continues to grow. Results of long-term prospective studies consistently identify persons with low levels of risk factors as having lifelong low levels of heart disease and stroke.3,4⇓ Moreover, these low levels of risk factors are related to healthy lifestyles. Data from the Nurses Health Study,5 for example, suggest that in women, maintaining a desirable body weight, eating a healthy diet, exercising regularly, not smoking, and consuming a moderate amount of alcohol could account for an 84% reduction in risk, yet only 3% of the women studied were in that category. Clearly, the majority of the causes of cardiovascular disease are known and modifiable. This 2002 update of the Guide acknowledges a number of advances in the field of primary prevention since 1997. Research continues to refine the recommendations on detection and management of established risk factors, including evidence against the safety and efficacy of interventions once thought promising (eg, antioxidant vitamins).6 This, in turn, has …

Environmental Correlates of Walking and Cycling: Findings From the Transportation, Urban Design, and Planning Literatures

Research in transportation, urban design, and planning has examined associations between physical environment variables and individuals’ walking and cycling for transport. Constructs, methods, and findings from these fields can be applied by physical activity and health researchers to improve understanding of environmental influences on physical activity. In this review, neighborhood environment characteristics proposed to be relevant to walking/cycling for transport are defined, including population density, connectivity, and land use mix. Neighborhood comparison and correlational studies with nonmotorized transport outcomes are considered, with evidence suggesting that residents from communities with higher density, greater connectivity, and more land use mix report higher rates of walking/cycling for utilitarian purposes than low-density, poorly connected, and single land use neighborhoods. Environmental variables appear to add to variance accounted for beyond sociodemographic predictors of walking/cycling for transport. Implications of the transportation literature for physical activity and related research are outlined. Future research directions are detailed for physical activity research to further examine the impact of neighborhood and other physical environment factors on physical activity and the potential interactive effects of psychosocial and environmental variables. The transportation, urban design, and planning literatures provide a valuable starting point for multidisciplinary research on environmental contributions to physical activity levels in the population.

Correlates of physical activity: why are some people physically active and others not?

Physical inactivity is an important contributor to non-communicable diseases in countries of high income, and increasingly so in those of low and middle income. Understanding why people are physically active or inactive contributes to evidence-based planning of public health interventions, because effective programmes will target factors known to cause inactivity. Research into correlates (factors associated with activity) or determinants (those with a causal relationship) has burgeoned in the past two decades, but has mostly focused on individual-level factors in high-income countries. It has shown that age, sex, health status, self-efficacy, and motivation are associated with physical activity. Ecological models take a broad view of health behaviour causation, with the social and physical environment included as contributors to physical inactivity, particularly those outside the health sector, such as urban planning, transportation systems, and parks and trails. New areas of determinants research have identified genetic factors contributing to the propensity to be physically active, and evolutionary factors and obesity that might predispose to inactivity, and have explored the longitudinal tracking of physical activity throughout life. An understanding of correlates and determinants, especially in countries of low and middle income, could reduce the eff ect of future epidemics of inactivity and contribute to effective global prevention of non-communicable diseases.

Age and gender differences in objectively measured physical activity in youth.

PURPOSE The purpose of this study was to evaluate age and gender differences in objectively measured physical activity (PA) in a population-based sample of students in grades 1-12. METHODS Participants (185 male, 190 female) wore a CSA 7164 accelerometer for 7 consecutive days. To examine age-related trends, students were grouped as follows: grades 1-3 (N = 90), grades 4-6 (N = 91), grades 7-9 (N = 96), and grades 10-12 (N = 92). Bouts of PA and minutes spent in moderate-to-vigorous PA (MVPA) and vigorous PA (VPA) were examined. RESULTS Daily MVPA and VPA exhibited a significant inverse relationship with grade level, with the largest differences occurring between grades 1-3 and 4-6. Boys were more active than girls; however, for overall PA, the magnitudes of the gender differences were modest. Participation in continuous 20-min bouts of PA was low to nonexistent. CONCLUSION Our results support the notion that PA declines rapidly during childhood and adolescence and that accelerometers are feasible alternatives to self-report methods in moderately sized population-level surveillance studies.

Environmental and policy interventions to promote physical activity.

BACKGROUND Because most adults in industrialized countries do not meet physical activity guidelines, population-wide interventions are needed. Environmental and policy interventions are based on ecological models of behavior and have the potential to influence entire populations. Ecological models are particularly applicable to physical activity because the behavior must be done in specific physical settings. Cross-sectional data indicate that environmental and policy variables are associated with physical activity behaviors of young people and adults. METHOD Seven published evaluations of environmental and policy interventions to increase physical activity were reviewed. RESULTS Two studies showed that placing signs encouraging stair use can be effective. Quasi-experimental evaluations provided limited evidence that broad environmental changes can be effective. Large-scale policy interventions are currently being conducted in several countries. PROPOSED MODEL: A model describing the development of policy and environmental interventions is proposed, in the hope of stimulating more research in this area. Advocacy or planning groups identify and work with agencies that control policies and environments that can be altered to increase physical activity. Educational and policy/environmental interventions are seen as complementary. CONCLUSION Lack of conceptual models and the inherent difficulties of evaluation have hampered research on environmental and policy interventions. Further research is needed, and practitioners and researchers should work together to evaluate programs.

The development of scales to measure social support for diet and exercise behaviors

The purpose of this study was to develop measures of perceived social support specific to health-related eating and exercise behaviors. In Study I, specific supportive and nonsupportive behaviors were identified through interviews with 40 individuals making health-behavior changes. In Study II, items derived from the interviews were administered to 171 subjects. Support from family and friends was assessed separately for both diet and exercise habits. Meaningful factors were identified for each of the four scales, and some factors were similar for family and friend scales. Both test-retest and internal consistency reliabilities were acceptable, and six factors can be used as subscales. Social support scales were correlated with respective self-reported dietary and exercise habits, providing evidence of concurrent criterion-related validity. A measure of general social support was not related to the specific social support scales or to reported health habits. These scales are among the first measures of social support behaviors specific to dietary- and exercise-habit change.

Using objective physical activity measures with youth: How many days of monitoring are needed?

PURPOSE The purpose of this study was to establish the minimal number of days of monitoring required for accelerometers to assess usual physical activity in children. METHODS A total of 381 students (189 M, 192 F) wore a CSA 7164 uniaxial accelerometer for seven consecutive days. To examine age-related trends students were grouped as follows: Group I: grades 1-3 (N = 92); Group II: grades 4-6 (N = 98); Group III: grades 7-9 (N = 97); Group IV: grades 10-12 (N = 94). Average daily time spent in moderate-to-vigorous physical activity (MVPA) was calculated from minute-by-minute activity counts using the regression equation developed by Freedson et al. (1997). RESULTS Compared with adolescents in grades 7 to 12, children in grades 1 to 6 exhibited less day-to-day variability in MVPA behavior. Spearman-Brown analyses indicated that between 4 and 5 d of monitoring would be necessary to a achieve a reliability of 0.80 in children, and between 8 and 9 d of monitoring would be necessary to achieve a reliability of 0.80 in adolescents. Within all grade levels, the 7-d monitoring protocol produced acceptable estimates of daily participation in MVPA (R = 0.76 (0.71-0.81) to 0.87 (0.84-0.90)). Compared with weekdays, children exhibited significantly higher levels of MVPA on weekends, whereas adolescents exhibited significantly lower levels of MVPA on weekends. Principal components analysis revealed two distinct time components for MVPA during the day for children (early morning, rest of the day), and three distinct time components for MVPA during the day for adolescents (morning, afternoon, early evening). CONCLUSIONS These results indicate that a 7-d monitoring protocol provides reliable estimates of usual physical activity behavior in children and adolescents and accounts for potentially important differences in weekend versus weekday activity behavior as well as differences in activity patterns within a given day.

Personal and environmental factors associated with physical inactivity among different racial-ethnic groups of U.S. middle-aged and older-aged women.

Personal, program-based, and environmental barriers to physical activity were explored among a U.S. population-derived sample of 2,912 women 40 years of age and older. Factors significantly associated with inactivity included American Indian ethnicity, older age, less education, lack of energy, lack of hills in ones neighborhood, absence of enjoyable scenery, and infrequent observation of others exercising in ones neighborhood. For all ethnic subgroups, caregiving duties and lacking energy to exercise ranked among the top 4 most frequently reported barriers. Approximately 62% of respondents rated exercise on ones own with instruction as more appealing than undertaking exercise in an instructor-led group, regardless of ethnicity or current physical activity levels. The results underscore the importance of a multifaceted approach to understanding physical activity determinants in this understudied, high-risk population segment.

The effects of a 2-year physical education program (SPARK) on physical activity and fitness in elementary school students. Sports, Play and Active Recreation for Kids.

OBJECTIVES This study evaluated a health-related physical education program for fourth- and fifth-grade students designed to increase physical activity during physical education classes and outside of school. METHODS Seven schools were assigned to three conditions in a quasi-experimental design. Health-related physical education was taught by physical education specialists or trained classroom teachers. Students from these classes were compared with those in control classes. Analyses were conducted on 955 students with complete data. RESULTS Students spent more minutes per week being physically active in specialist-led (40 min) and teacher-led (33 min) physical education classes than in control classes (18 min; P < .001). After 2 years, girls in the specialist-led condition were superior to girls in the control condition on abdominal strength and endurance (P < .001) and cardiorespiratory endurance (P < .001). There were no effects on physical activity outside of school. CONCLUSIONS A health-related physical education curriculum can provide students with substantially more physical activity during physical education classes. Improved physical education classes can potentially benefit 97% of elementary school students.