SALLIS, J. F., J. J. PROCHASKA, and W. C. TAYLOR. A review of correlates of physical activity of children and adolescents. Med. Sci. Sports Exerc., Vol. 32, No. 5, pp. 963‐975, 2000. Background: Understanding the factors that influence physical activity can aid the design of more effective interventions. Previous reviews of correlates of youth physical activity have produced conflicting results. Methods: A comprehensive review of correlates of physical activity was conducted, and semiquantitative results were summarized separately for children (ages 3‐12) and adolescents (ages 13‐18). The 108 studies evaluated 40 variables for children and 48 variables for adolescents. Results: About 60% of all reported associations with physical activity were statistically significant. Variables that were consistently associated with children’s physical activity were sex (male), parental overweight status, physical activity preferences, intention to be active, perceived barriers (inverse), previous physical activity, healthy diet, program/facility access, and time spent outdoors. Variables that were consistently associated with adolescents’ physical activity were sex (male), ethnicity (white), age (inverse), perceived activity competence, intentions, depression (inverse), previous physical activity, community sports, sensation seeking, sedentary after school and on weekends (inverse), parent support, support from others, sibling physical activity, direct help from parents, and opportunities to exercise. Conclusion: These consistently related variables should be confirmed in prospective

A review of correlates of physical activity of children and adolescents.

Purpose:We established accelerometer count ranges for the Computer Science and Applications, Inc. (CSA) activity monitor corresponding to commonly employed MET categories.Methods:Data were obtained from 50 adults (25 males, 25 females) during treadmill exercise at three different speeds (4.8

Calibration of the Computer Science and Applications, Inc. accelerometer.

Wearable sensor technologies are essential to the realization of personalized medicine through continuously monitoring an individual's state of health. Sampling human sweat, which is rich in physiological information, could enable non-invasive monitoring. Previously reported sweat-based and other non-invasive biosensors either can only monitor a single analyte at a time or lack on-site signal processing circuitry and sensor calibration mechanisms for accurate analysis of the physiological state. Given the complexity of sweat secretion, simultaneous and multiplexed screening of target biomarkers is critical and requires full system integration to ensure the accuracy of measurements. Here we present a mechanically flexible and fully integrated (that is, no external analysis is needed) sensor array for multiplexed in situ perspiration analysis, which simultaneously and selectively measures sweat metabolites (such as glucose and lactate) and electrolytes (such as sodium and potassium ions), as well as the skin temperature (to calibrate the response of the sensors). Our work bridges the technological gap between signal transduction, conditioning (amplification and filtering), processing and wireless transmission in wearable biosensors by merging plastic-based sensors that interface with the skin with silicon integrated circuits consolidated on a flexible circuit board for complex signal processing. This application could not have been realized using either of these technologies alone owing to their respective inherent limitations. The wearable system is used to measure the detailed sweat profile of human subjects engaged in prolonged indoor and outdoor physical activities, and to make a real-time assessment of the physiological state of the subjects. This platform enables a wide range of personalized diagnostic and physiological monitoring applications.

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Fully integrated wearable sensor arrays for multiplexed in situ perspiration analysis

(2000). Assessment of Physical Activity by Self-Report: Status, Limitations, and Future Directions. Research Quarterly for Exercise and Sport: Vol. 71, No. sup2, pp. 1-14.

Assessment of physical activity by self-report: status, limitations, and future directions.

CONTEXT. Environmental factors are suggested to play a major role in physical activity (PA) and other obesity-related behaviors, yet there is no national research on the relationship between disparity in access to recreational facilities and additional impact on PA and overweight patterns in US adolescents. 

OBJECTIVE. In a nationally representative cohort, we sought to assess the geographic and social distribution of PA facilities and how disparity in access might underlie population-level PA and overweight patterns. 

DESIGN, SETTING, AND PARTICIPANTS. Residential locations of US adolescents in wave I (1994–1995) of the National Longitudinal Study of Adolescent Health (N = 20745) were geocoded, and a 8.05-km buffer around each residence was drawn (N = 42857 census-block groups [19% of US block groups]). PA facilities, measured by national databases and satellite data, were linked with Geographic Information Systems technology to each respondent. Logistic-regression analyses tested the relationship of PA-related facilities with block-group socioeconomic status (SES) (at the community level) and the subsequent association of facilities with overweight and PA (at the individual level), controlling for population density. 

MAIN OUTCOME MEASURES. Outcome measures were overweight (BMI ≥ 95th percentile of the Centers for Disease Control and Prevention/National Center for Health Statistics growth curves) and achievement of ≥5 bouts per week of moderate-vigorous PA. 

RESULTS. Higher-SES block groups had a significantly greater relative odds of having 1 or more facilities. Low-SES and high-minority block groups were less likely to have facilities. Relative to zero facilities per block group, an increasing number of facilities was associated with decreased overweight and increased relative odds of achieving ≥5 bouts per week of moderate-vigorous PA. 

CONCLUSIONS. Lower-SES and high-minority block groups had reduced access to facilities, which in turn was associated with decreased PA and increased overweight. Inequality in availability of PA facilities may contribute to ethnic and SES disparities in PA and overweight patterns.

/pdf/inequality-in-the-built-environment-underlies-key-health-4ktbglkmwo.pdf

Inequality in the Built Environment Underlies Key Health Disparities in Physical Activity and Obesity

There is need to develop low cost, practical, and accurate measures of physical activity in children and adolescents, and self-report is a promising methodology for children that is applicable for large studies. The purpose of the present study was to assess the reliability and validity of s

Seven-day recall and other physical activity self-reports in children and adolescents

The associations of physical activity and cardiovascular fitness with cardiovascular disease risk factors were studied in 88 male adults, 180 female adults, 148 male children, and 142 female children. Subjects were families recruited from elementary schools in San Diego, California. Fitness (VO2 max) was measured by a submaximal cycle ergometer test. Physical activity was assessed by seven-day recall interview, yielding caloric expenditure, and by a simple self-rating of activity level. Risk factors included blood pressure, high density lipoprotein (HDL) cholesterol, the ratio of high density lipoproteins to low density lipoproteins (LDL), and body mass index. For all subgroups, fitness was strongly and significantly correlated with virtually all risk factors. After adjustment for body mass index, most fitness-risk factor associations were no longer significant. Seven-day caloric expenditure was significantly correlated with HDL/LDL only in female adults and children. The activity rating was significantly correlated with body mass index in all subgroups and with HDL/LDL in female adults and male adults. The simple activity rating tended to be correlated with fitness. The pattern of association was similar for adults and children.

Relation of cardiovascular fitness and physical activity to cardiovascular disease risk factors in children and adults

An integrated system for coding direct observations of children's dietary and physical activity behaviors was developed. Associated environmental events were also coded, including physical location, antecedents, and consequences. To assess the instrument's reliability and validity, 42 children, aged 4 to 8 years, were observed for 8 consecutive weeks at home and at school. Results indicated that four 60-min observations at home produced relatively stable estimates for most of the 10 dimensions. Interobserver reliabilities during live and videotaped observations were high, with the exception of "consequences" categories that occurred in less than 1% of observed intervals. Evidence of validity was provided by findings that antecedents were associated with respective dietary and physical activity behaviors. The five physical activity categories were validated by heartrate monitoring in a second study. The Behaviors of Eating and Activity for Children's Health Evaluation System is appropriate for studying influences on diet and physical activity in children in a variety of settings.

BEACHES: an observational system for assessing children's eating and physical activity behaviors and associated events.

The performance of the Caltrac accelerometer was studied in elementary school-age children under field and laboratory conditions. In Study 1, 35 children (20 boys, 15 girls, mean age = 10.8 yr) wore the accelerometer and a heart rate (HR) monitor for 2 d. Caltrac activity counts per hour were compared to the mean "activity HR", which was calculated by subtracting the mean of the five lowest HRs of the day from each recorded HR. Pearson r's between accelerometer and activity HR were 0.54 (P less than 0.001) on day 1 and 0.42 (P less than 0.02) on day 2. Inter-instrument reliability in the field was r = 0.96. Both accelerometer and HR data were significantly correlated with physical activity recalls of the same day. In Study 2, 15 children walked/ran for 10 min at 3, 4, and 5 mph on a horizontal treadmill while wearing two accelerometers. Oxygen uptake was directly measured each minute. Reliability of the Caltracs in the laboratory was 0.89. Activity count correlated r = 0.82 (SEE = 23%) with net calorie cost per kg of body weight. Net caloric expenditure per kg of weight was 0.101 kcal.kg-1.d-1 per Caltrac activity count. These data support the use of the Caltrac accelerometer as a physical activity measure for school-age children, and the objective data tended to corroborate the children's short-term activity recalls.

The Caltrac accelerometer as a physical activity monitor for school-age children.

It is believed that families are important influences on the development of health habits, and the purpose of the present study was to examine the familial aggregation of physical activity. Physical activity habits were assessed by standardized interview in adults and children in 95 Anglo families and 111 Mexican-American families. The results indicated a moderate degree of aggregation of physical activity in both samples, and adjustment for body mass index was inconsequential. Intrafamily correlations tended to be higher in Mexican-Americans. Mother-child correlations usually were higher than father-child correlations. These findings support the hypothesis that the family is a significant influence on physical activity.

Michael J. Buono

Papers

Seven-day recall and other physical activity self-reports in children and adolescents

Relation of cardiovascular fitness and physical activity to cardiovascular disease risk factors in children and adults

BEACHES: an observational system for assessing children's eating and physical activity behaviors and associated events.

The Caltrac accelerometer as a physical activity monitor for school-age children.

Aggregation of physical activity habits in Mexican-American and Anglo families