No abstract is provided for this article.
Purpose. The present study was grounded in the notion that previously identified physical activity determinants were associated in reverse with television viewing. Identifying demographic and psychosocial correlates and other potential determinants of television viewing may allow for the development and conceptualization of models and interventions to reduce sedentary behavior. Design. Cross-sectional data from self-report measures were analyzed using multiple hierarchical regression. Setting. Data were collected from 1995 to 1996 on seniors attending a large public university in southern California. Sample. Subjects were 321 female and 255 male university seniors attending a public university in southern California. The sample's ethnic distribution was 53.8% European-American, 16.3% Latino, 16.6% Asian/Pacific Islander, 16.1% African-American, and 4.3% other. Measures. Typical television viewing practices on weekdays and weekends were assessed using self-report items. Physical activity determinants were assessed using self-report measures derived from social cognitive theory and the transtheoretical model of behavior change. Results. The variables explaining a significant amount of variance after controlling for ethnicity and employment status in females were barriers to physical activity (p < . 05), body image dissatisfaction (p < .01), and processes of change (p < .02). The entire model for females captured 16% of the variance, with the psychosocial variables accounting for 8% of the variance. The significant variables in the male model were quality of life (p < . 01) and grade point average (p < .03). The full model accounted for 15% of the variance, with nondemographic variables accounting for 5% of the variance in television viewing. Conclusions. Relationships between television viewing and potential determinants were found. However, additional variables that may influence the amount of television viewing need to be conceptualized and investigated.
There is evidence that low to moderate levels of physical activity can reduce risk of cardiovascular disease, even though they do not produce substantial changes in cardiorespiratory function. In this study of a representative population sample of 5,930 adult men and women, participants in moderate-intensity activities, such as walking and climbing stairs, were compared with nonparticipants. Men and women who reported more moderate activities were less overweight than sedentary peers. Moderate activity was associated with more risk factor benefits in men than in women. The apparent health benefits of moderate-intensity physical activity have implications for public health education.
Background: In 2005, investigators convened by the National Cancer Institute recommended development of standardized protocols for accelerometer use and reporting decision rules in articles. A literature review was conducted to document accelerometer methods and decision rule reporting in youth physical activity articles from 2005−2010. Methods: Nine electronic databases identified 273 articles that measured physical activity and/or sedentary behavior using the most-used brand of accelerometer (ActiGraph). Six key methods were summarized by age group (preschool, children, and adolescents) and trends over time were examined. Results: Studies using accelerometers more than doubled from 2005−2010. Methods included 2 ActiGraph models, 6 epoch lengths, 6 nonwear definitions, 13 valid day definitions, 8 minimum wearing day thresholds, 12 moderate-intensity physical activity cut points, and 11 sedentary cut points. Child studies showed the most variation in methods and a trend toward more variability in cut points over time. Decision rule reporting improved, but only 54% of papers reported on all methods. Conclusion: The increasing diversity of methods used to process and score accelerometer data for youth precludes comparison of results across studies. Decision rule reporting is inconsistent, and trends indicate declining standardization of methods. A methodological research agenda and consensus process are proposed.
The human metallothionein IIA (hMT-IIA) gene contains two enhancer elements whose activity is induced by heavy-metal ions such as Cd2+. To determine the nature of the relationship between the metal-responsive elements and the element(s) responsible for the basal activity of the enhancers, the basal-level enhancer element(s), the hMT-IIA enhancers were subjected to mutational analysis. We show that deletion of the metal-responsive elements had no effect on the basal activity of the enhancer but prevented further induction by Cd2+. On the other hand, replacement of the basal-level enhancer element with linker DNA led to inactivation of the enhancer both before and after treatment with Cd2+. Therefore, the metal-responsive elements seems to act as a positive modulator of enhancer function in the presence of heavy-metal ions. In addition to the two enhancers, the hMT-IIA promoter contained one other element, the GC box, required for its basal expression. Unlike deletion of the basal-level enhancer element, replacement of the GC box with linker DNA had no effect on the ability of the promoter to be induced by Cd2+.
Twenty-two potential correlates of children's physical activity were examined. Two hundred and one Mexican-American and 146 Anglo-American families with 4-year-old children were studied. Children's physical activity was directly observed in the evening at home on 4 visits for 1 hr each time. Anglo-American children and male children were found to be more active. Demographic variables explained 11% of the variance in children's physical activity. After adjusting for demographics, 3 children's variables and 6 social-family variables did not account for significantly more variance. Five environmental variables accounted for 11% additional variance. Variables observed concurrently with physical activity, such as time spent outdoors and prompts to be active, were highly associated with children's physical activity.
