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.

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.

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

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.

Influences of preschool policies and practices on children's physical activity

The objective of this study was to determine if moderate to vigorous physical activity (MVPA) of 3-5 year old preschool children varied with differences in policies/practices, and overall quality of preschools. A total of 266 children (47% males, 60% African American) from 9 preschools were observed for 1 hour on 3 different days. PA of children was observed twice per minute and scored as 1-5, with 1 for stationary/motionless and 5 for fast movement. Summary MVPA was calculated over the 3 days as percent of times observed at levels of 4 or 5, and percent of time at levels I or 2 as sedentary activity. A structured interview about PA policies was conducted with an administrator at each preschool and overall quality of the preschool was assessed using Early Childhood Environment Rating Scale-Revised Edition (ECERS-R). Preschools were divided into groups according to whether a specific policy/practice that would be logically hypothesized to promote PA was in place at the school. MVPA differences between groups of children was assessed using mixed ANOVA controlling for preschool. When preschools offered more field trips, and more college educated teachers, the children participated in more MVPA. Children who attended preschools with lower quality spent more time in sedentary activity. In conclusion, children in preschools which may have more resources and better quality appear to show both more sedentary behavior and more MVPA.

Nutrition and physical activity policies and practices in family child care homes in oregon : baseline findings from the healthy home child care project

Baseline findings from the Healthy Home Child Care Project include data from Family Child Care Providers (FCCPs) in Oregon (n=53) who completed assessments of nutrition and physical activity policies and practices and BMI data for children in the care of FCCPs (n=205). Results show that a significant percentage of FCCPs failed to meet child care standards in several areas and that 26.8% of children under the care of FCCPs were overweight or obese. These data supported the development of an Extension-delivered intervention specific to FCCPs in Oregon and highlight areas of concern that should be addressed through targeted trainings of FCCPs.