Physical activity in overweight and nonoverweight preschool children

OBJECTIVE To compare the physical activity levels of overweight and non overweight 3- to 5-y-old children while attending preschool. A secondary aim was to evaluate weight-related differences in hypothesized parental determinants of child physical activity behavior. DESIGN Cross-sectional study. SUBJECTS A total of 245, 3- to 5-y-olds ( 127 girls, 118 boys) and their parent(s) ( 242 mothers, 173 fathers) recruited from nine preschools. Overweight status determined using the age- and sex-specific 85th percentile for body mass index (BMI) from CDC Growth Charts. MEASUREMENTS Physical activity during the preschool day was assessed on multiple days via two independent objective measures-direct observation using the observation system for recording activity in preschools (OSRAP) and real-time accelerometry using the MTI/CSA 7164 accelerometer. Parents completed a take-home survey assessing sociodemographic information, parental height and weight, modeling of physical activity, support for physical activity, active toys and sporting equipment at home, child's television watching, frequency of park visitation, and perceptions of child competence. RESULTS Overweight boys were significantly less active than their nonoverweight peers during the preschool day. No significant differences were observed in girls. Despite a strong association between childhood overweight status and parental obesity, no significant differences were observed for the hypothesized parental influences on physical activity behavior. CONCLUSIONS Our results suggest that a significant proportion of overweight children may be at increased risk for further gains in adiposity because of low levels of physical activity during the preschool day.

Effects of physical activity intervention in youth : a review

Effects of physical activity interventions in youth: A review. International SportMed Journal. Vol.2 No.5 2001. The purpose of this paper is to review the peer-reviewed literature pertinent to physical activity interventions for children and adolescents. In order to provide a more quantitative conclusion regarding the effectiveness of these interventions, a meta-analytic approach was utilized in which effect sizes (the efficacy of each intervention or magnitude of the intervention effect was expressed as a standardized effect size, which represents the influence of the treatment or intervention on the dependent variable) from each study are pooled to provide a global estimate of effectiveness. A search of the relevant peer-reviewed literature was conducted using several computer-based databases, including MEDLINE, PYSCHLIT, SOCIAL SCIENCE INDEX, and SPORTS DISCUS. Manual searches were also made using the reference lists from recovered articles. Applying strict criteria for quality of design and assessment of physical activity, 10 studies were located, yielding a total of 44 effect sizes. The mean effect size was 0.47 (95% C.I. 0.28 – 0.66) suggesting that interventions have produced moderate increases in physical activity behavior. Effect sizes ranged from –0.61 to 2.5. Interventions focusing on increasing the amount of physical activity performed during regular physical education were more effective than those targeting overall levels of physical activity. Interventions were almost entirely school-based. Accordingly, the development and evaluation of community-based approaches for promoting physical activity among young people, especially older adolescents, remains an urgent priority for future research.

Validity and reliability of the 3-day physical activity recall in Singaporean adolescents

Childhood obesity and physical inactivity are major health concerns for the Singaporean government (Ministry of Health, Singapore [MOH], 2001). Data from the 1998 Singaporean National Health Survey indicate that 10.8–14.7% of Singaporean children ages 6–16 years are either overweight or obese (MOH, 2001). Although true population estimates of youth physical activity are not available, descriptive epidemiological studies conducted in the 1990s suggest that a large percentage of school-aged children in Singapore fail to meet established guidelines for participation in physical activity...

Adherence to physical activity and electronic media guidelines in Australian pre-school children

The aim of this study was to determine compliance with the National Association for Sport and Physical Education (NASPE) guideline for physical activity and American Academy of Pediatrics (AAP) recommendation for electronic media use among urban pre-school children in two large cities on the East Coast of Australia. Cross-sectional data were collected from 266 parents. Time spent using electronic media (watching television, DVDs or on the computer) and in physical activity were parent reported. The proportion who met each guideline was calculated. 56 per cent and 79% of children met the NASPE guideline on weekdays and weekends, respectively, while 73% and 70% met the AAP recommendation on weekdays and weekends, with no difference between boys and girls. A substantial minority do not meet physical activity and electronic media use recommendations, highlighting the need to better understand what factors contribute to physical activity and electronic media use among this group of pre-schoolers.

Compliance with physical activity guidelines : prevalence in a population of children and youth

PURPOSE To use objective monitoring of physical activity to determine the percentages of children and youth in a population that met physical activity guidelines. METHODS A total of 375 students in grades 1–12 wore an accelerometer (CSA 7164) for seven consecutive days. Bouts of continuous activity and accumulation of minutes spent in physical activity at various intensities were calculated to determine how many students met three physical activity guidelines. RESULTS Over 90% of students met Healthy People 2010, Objective 22.6 and nearly 70% met the United Kingdom Expert Consensus Group guideline, both of which recommend daily accumulation of moderate physical activity. Less than 3% met Healthy People 2010, Objective 22.7, which calls for bouts of continuous vigorous physical activity. For the United Kingdom Expert Consensus Group guideline, compliance decreased markedly with age, but gender differences were not statistically significant. CONCLUSIONS Prevalence estimates for compliance with national physical activity guidelines varied markedly for the three guidelines examined. Objective monitoring of physical activity in youth appears to be feasible and may provide more accurate prevalence rates than self-report measures.

Associations between physical activity and other health behaviors in a representative sample of US adolescents

OBJECTIVES This study examined the associations between physical activity and other health behaviors in a representative sample of US adolescents. METHODS In the 1990 Youth Risk Behavior Survey, 11631 high school students provided information on physical activity; diet; substance use; and other negative health behaviors. Logistic regression analyses examined associations between physical activity and other health behaviors in a subset of 2652 high-active and 1641 low-active students. RESULTS Low activity was associated with cigarette smoking, marijuana use, lower fruit and vegetable consumption, greater television watching, failure to wear a seat belt, and low perception of academic performance. For consumption of fruit, television watching, and alcohol consumption, significant interactions were found with race/ethnicity or sex, suggesting that sociocultural factors may affect the relationships between physical activity and some health behaviors. CONCLUSIONS Low physical activity was associated with several other negative health behaviors in teenagers. Future studies should examine whether interventions for increasing physical activity in youth can be effective in reducing negative health behaviors.

Correlates of physical activity behavior in rural youth

The purpose of this study was to identify correlates of physical activity behavior in a sample of rural, predominantly African American youth. Three hundred sixty-one fifth-grade students from two rural counties in South Carolina (69% African American, median age = II years) completed a questionnaire designed to measure beliefs and social influences regarding physical activity, physical activity self-efficacy, perceived physical activity habits of family members and friends, and access to exercise and fitness equipment at home. After school physical activity and television watching were assessed using the Previous Day Physical Activity Recall (PDPAR). Students were classified as physically active according to a moderate physical activity standard: two or more 30-min blocks at an intensity of 3 METs (metabolic equivalents) or greater, and a vigorous physical activity standard: one or more 30-min blocks at an intensity of 6 METs or greater According to the moderate physical activity standard, 34.9% of students were classified as low-active. Multivariate analysis revealed age, gender television watching, and exercise equipment at home to be significant correlates of low activity status. According to the vigorous physical activity standard, 32.1 % of the students were classified as low-active. Multivariate analysis revealed age, gender television watching, and self-efficacy with respect to seeking support for physical activity to be significant correlates of low activity status. In summary, gender and the amount of television watching were found to be the most important correlates of physical activity in rural, predominantly African American youth.

Accelerometer validity and placement for detection of changes in physical activity in dogs under controlled conditions on a treadmill

The objective of the research was to determine the optimal location and method of attachment for accelerometer-based motion sensors, and to validate their ability to differentiate rest and increases in speed in healthy dogs moving on a treadmill. Two accelerometers were placed on a harness between the scapulae of dogs with one in a pouch and one directly attached to the harness. Two additional accelerometers were placed (pouched and not pouched) ventrally on the dog's collar. Data were recorded in 1. s epochs with dogs moving in stages lasting 3. min each on a treadmill: (1) at rest, lateral recumbency, (2) treadmill at 0% slope, 3. km/h, (3) treadmill at 0% slope, 5. km/h, (4) treadmill at 0% slope, 7. km/h, (5) treadmill at 5% slope, 5. km/h, and; (6) treadmill at 5% slope, 7. km/h. Only the harness with the accelerometer in a pouch along the dorsal midline yielded statistically significant increases (P< 0.05) in vector magnitude as walking speed of the dogs increased (5-7. km/h) while on the treadmill. Statistically significant increases in vector magnitude were detected in the dogs as the walking speed increased from 5 to 7. km/h, however, changes in vector magnitude were not detected when activity intensity was increased as a result of walking up a 5% grade. Accelerometers are a valid and objective tool able to discriminate between and monitor different levels of activity in dogs in terms of speed of movement but not in energy expenditure that occurs with movement up hill.

Objective measurement of physical activity in youth : current issues, future directions

Second-generation activity monitors have revolutionized the way in which we measure youth physical activity. Use of the monitors avoids the problems associated with self-report methods and allows for the estimation of physical activity patterns over time. This article examines important methodological issues related to the use of activity monitors in children and adolescents.

Every step counts : promoting activity among obese adolescents

In separate articles, two projects are described. The first describes a community project in Rockhampton to encourage people to walk more often and the second, a project to encourage more walking in obese adolescents

Psychosocial correlates of physical activity in white and African-American girls

Purpose To evaluate the relative utility of the Theory of Reasoned Action (TRA) and the Theory of Planned Behavior (TPB) in explaining intentions and physical activity behavior in white and African-American eighth-grade girls. Methods One-thousand-thirty white and 1114 African-American eighth-grade girls (mean age 13.6 ± 0.7 years) from 31 middle schools in South Carolina completed a 3-day physical activity recall and a questionnaire assessing attitudes, subjective norms, perceived behavioral control, self-efficacy, and intentions related to regular participation in moderate-to-vigorous physical activity (MVPA). Results Among Whites, 17% of the variance in intentions was contributed by subjective norms and attitude, with intentions accounting for 8% of the variance in MVPA. The addition of perceived behavioral control and self-efficacy to the TRA significantly improved the prediction of intentions and MVPA accounting for 40% and 10% of the variance, respectively. Among African-Americans, subjective norms and attitude accounted for 13% of the variance in intentions, with intentions accounting for only 3% of the variance in MVPA. The addition of perceived behavioral control and self-efficacy to the TRA significantly improved the prediction of intentions and MVPA accounting for 28% and 5% of the variance, respectively. Conclusions The results provided limited empirical support for the TPB among white adolescent girls; however, our findings suggest that the planned behavior framework has limited utility among African-American adolescent girls. The relatively weak link between intentions and MVPA observed in both population groups suggest that constructs external to the TPB may be more important mediators of physical activity behavior in adolescent girls.

Physical activity correlates in adolescent girls who differ by weight status

Objective This study compared correlates of physical activity (PA) among African-American and white girls of different weight groups to guide future interventions. Research Methods and Procedures Participants were 1015 girls (mean age, 14.6 years; 45% African-American) from 12 high schools in South Carolina who served as control subjects for a school-based intervention. Post-intervention measures obtained at the end of ninth grade were used. PA was measured using the Three-Day PA Recall, and a questionnaire measured social-cognitive and environmental variables thought to mediate PA. Height and weight were measured, and BMI was calculated. Girls were stratified by race and categorized into three groups, based on BMI percentiles for girls from CDC growth charts: normal (BMI < 85th percentile), at risk (BMI, 85th to 94th percentile), and overweight (BMI ≥ 95th percentile). Girls were further divided into active and low-active groups, based on a vigorous PA standard (average of one or more 30-minute blocks per day per 3-day period). Mixed-model ANOVA was used to compare factors among groups, treating school as a random effect Results None of the social-cognitive or environmental variables differed by weight status for African-American or white girls. Perceived behavioral control and sports team participation were significantly higher in girls who were more active, regardless of weight or race group. In general, social-cognitive variables seem to be more related to activity in white girls, whereas environmental factors seem more related to activity in African-American girls. Discussion PA interventions should be tailored to the unique needs of girls based on PA levels and race, rather than on weight status alone.

Physical activity and physical fitness in African-American girls with and without obesity

Lack of physical activity and low levels of physical fitness are thought to be contributing factors to the high prevalence of obesity in African-American girls, To examine this hypothesis, we compared habitual physical activity and physical fitness in 54 African-American girls with obesity and 96 African-American girls without obesity residing in rural South Carolina, Participation in vigorous (greater than or equal to 6 METs) (VPA) or moderate and vigorous physical activity (greater than or equal to 4 METs) (MVPA) was assessed on three consecutive days using the Previous Day Physical Activity Recall, Cardiorespiratory fitness was assessed using the PWC 170 cycle ergometer test, Upper body strength was determined at two sites via isometric cable tensiometer tests, Relative to their counterparts without obesity, girls with obesity reported significantly fewer 30-minute blocks of VPA (0.90 +/- 0.14 vs. 1.3 +/- 0.14) and MVPA (1.2 +/- 0.18 vs. 1.7 +/- 0.16) (p<0.01), Within the entire sample, VPA and MVPA were inversely associated with body mass index (r=-0.17 and r=-0.19) and triceps skinfold thickness (r=-0.19 and r=-0.22) (p<0.05), In the PWC 170 test and isometric strength tests, girls with obesity demonstrated absolute scores that were similar to, or greater than, those of girls without obesity; however, when scores were expressed relative to bodyweight, girls with obesity demonstrated significantly lower values (p<0.05). The results support the hypothesis that lack of physical activity and low physical fitness are important contributing factors in the development and/or maintenance of obesity in African-American girls.

Hyperbranched polymer-gold nanoparticle assemblies : role of polymer architecture in hybrid assembly formation and SERS activity

Plasmonic gold nano-assemblies that self-assemble with the aid of linking molecules or polymers have the potential to yield controlled hierarchies of morphologies and consequently result in materials with tailored optical (e.g. localized surface plasmon resonances (LSPR)) and spectroscopic properties (e.g. surface enhanced Raman scattering (SERS)). Molecular linkers that are structurally well-defined are promising for forming hybrid nano-assemblies which are stable in aqueous solution and are increasingly finding application in nanomedicine. Despite much ongoing research in this field, the precise role of molecular linkers in governing the morphology and properties of the hybrid nano-assemblies remains unclear. Previously we have demonstrated that branched linkers, such as hyperbranched polymers, with specific anchoring end groups can be successfully employed to form assemblies of gold NPs demonstrating near-infrared SPRs and intense SERS scattering. We herein introduce a tailored polymer as a versatile molecular linker, capable of manipulating nano-assembly morphologies and hot-spot density. In addition, this report explores the role of the polymeric linker architecture, specifically the degree of branching of the tailored polymer in determining the formation, morphology and properties of the hybrid nano-assemblies. The degree of branching of the linker polymer, in addition to the concentration and number of anchoring groups, is observed to strongly influence the self-assembly process. The assembly morphology shifts primarily from 1D-like chains to 2D plates and finally to 3D-like globular structures, with increase in degree of branching. Insights have been gained into how the morphology influences the SERS performance of these nano-assemblies with respect to hot-spot density. These findings supplement the understanding of the morphology determining nano-assembly formation and pave the way for the possible application of these nano-assemblies as SERS bio-sensors for medical diagnostics.

Invasive activity and chemotactic response to growth factors by Kaposi's sarcoma cells

Kaposi's sarcoma (KS) is a relatively low grade neoplasm, classically occurring in the skin of elderly men. A more virulent and invasive form of Kaposi's sarcoma has been described in patients with acquired immune deficiency syndrome (AIDS). The origin and identification of the tumor cells in these lesions is controversial. Here we have studied the behavior of cells derived from KS lesions in an in vitro assay which measures the ability of cells to invade through a reconstituted basement membrane. In agreement with previous work, KS cells obtained under selective culture conditions were invasive showing activity comparable to that of malignant tumor cells. Normal fibroblasts, smooth muscle cells, and endothelial cells did not demonstrate invasive behavior under the same experimental conditions. To characterize further the nature of the KS cells we tested the chemotactic response of cells from the most invasive line to a variety of growth factors and compared their response to those of fibroblasts, smooth muscle, and endothelial cells. These studies suggest that normal cells respond to a unique repertoire of chemotactic factors. The chemotactic response of the KS cells most closely resembled that of smooth muscle cells and was quite distinct from endothelial cells. These results indicate that the KS-derived cultures contain invasive cells with a smooth muscle cell-like phenotype.