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Simon J Marshall

Publications and source records attributed to Simon J Marshall.

11 recordsLinked to original sources
PubMed2007

Race/ethnicity, social class, and leisure-time physical inactivity.

PURPOSE: The aims of this study were to determine 1) prevalence of leisure-time physical inactivity in a nationally representative sample of non-Hispanic white, non-Hispanic black, and Hispanic men and women; 2) prevalence of leisure-time inactivity by racial/ethnic group across social class indicators; and 3) the relationship between leisure-time inactivity and occupational physical activity, independent of other social class indicators. METHODS: The National Physical Activity and Weight Loss Survey was a telephone survey of noninstitutionalized U.S. adults (4695 men, 6516 women) conducted by random digit dialing between September and December 2002. Self-reported physical activity was assessed using questions from the 2001 Behavioral Risk Factor Surveillance System. Respondents who reported no moderate- or vigorous-intensity physical activity during leisure time in a usual week were classified as inactive. Indicators of social class were education, family income, employment status, and marital status. RESULTS: Age-adjusted prevalence of leisure-time inactivity was 9.9% +/- 0.6 SE (standard error) and 12.0 +/- 0.6 for white men and women, respectively; 19.0 +/- 2.5 and 25.2 +/- 2.1 for non-Hispanic black men and women, and 20.9 +/- 2.1 and 27.3 +/- 2.5 for Hispanic men and women. Within each racial/ethnic group, prevalence of leisure-time inactivity was highest among participants of lower social class. Differences in inactivity by racial/ethnic group were less evident after adjustment for social class. Odds of inactivity were similar across quartiles of occupational physical activity after adjustment for age, sex, and social class. CONCLUSIONS: Non-Hispanic blacks and Hispanics were more inactive during their leisure time than were non-Hispanic whites. Social class but not occupational physical activity seems to moderate the relationship between race/ethnicity and leisure-time physical inactivity.

Adolescent↗
PubMed2006

Cross-sectional and longitudinal associations between TV viewing and girls' body mass index, overweight status, and percentage of body fat.

OBJECTIVE: To assess cross-sectional and longitudinal relations between television (TV) viewing and girls' body mass index (BMI), weight status, and percentage of body fat. STUDY DESIGN: Participants included 169 girls who were measured at ages 7, 9, and 11 years. Height and weight were measured and used to calculate girls' BMI and to classify their weight status. Girls' percentage of body fat was assessed with the use of dual-energy x-ray absorptiometry. Mothers reported the hours per day that girls watched TV on a typical day. RESULTS: No significant cross-sectional associations were identified. Results from longitudinal analyses showed that in comparison to girls who never exceeded the American Academy of Pediatrics TV viewing recommendations (ie, watched </= 2 hours of TV per day), girls who exceeded recommendations at ages 7, 9, and 11 years were 13.2 times more likely be overweight at age 11, were 4.7 times more likely to become overweight between ages 7 and 11, had significantly higher BMI and percentage body fat at age 11, and exhibited significantly greater increases in BMI between ages 7 and 11. CONCLUSIONS: Interventions that target reductions in TV viewing among 7- to 11-year-old girls may help to reduce their risk of weight gain during late childhood.

Absorptiometry, Photon↗
PubMed2005

A descriptive epidemiology of screen-based media use in youth: a review and critique.

The purpose of this systematic review was to (i) estimate the prevalence and dose of television (TV) viewing, video game playing and computer use, and (ii) assess age-related and (iii) secular trends in TV viewing among youth (< or = 18 yr). Ninety studies published in English language journals between 1949 and 2004 were included, presenting data from 539 independent samples (the unit of analysis). Results suggest contemporary youth watch on average 1.8-2.8 h of TV per day, depending on age and gender. Most (66%) are "low users" (< 2 h day(-1)) of TV but 28% watch more than 4 h day(-1). Boys and girls with access to video games spend approximately 60 and 23 min day(-1), respectively, using this technology. Computer use accounts for an additional 30 min day(-1). Age-specific data suggest TV viewing decreases during adolescence, but those considered "high users" at young ages are likely to remain high users when older. For children with access to a television set, the number of hours spent viewing does not appear to have increased over the past 50 years.

Adolescent↗
PubMed2004

Physical activity and sedentary behaviours in youth: issues and controversies.

There is growing concern over the effects of sedentary lifestyles on the health of young people. Recent rapid increases in juvenile obesity have received a great deal of attention in the scientific and popular press and have been attributed partly to television viewing, computer games and other sedentary behaviours. These are thought to compete with physical activity. There is a 'moral panic' concerning the 'couch kids' culture in modern western society. Project STIL (Sedentary Teenagers and Inactive Lifestyles) at Loughborough University is investigating 'what young people do' and focuses on active and inactive pursuits chosen in their leisure time. The following issues are addressed in this paper with specific reference to young people: how do we define 'sedentary behaviour' and do key sedentary behaviours displace physical activity? Are key sedentary behaviours obesogenic? What are the secular trends for children and youth for TV viewing? Our results for young people suggest that: 1. TV viewing and video-game playing are largely uncorrelated with physical activity, suggesting that there is time for both 2. meta-analytic findings show that body fatness is not related in any clinically meaningful way with key sedentary behaviours 3. although more children and youth have greater access to TVs than in previous generations, the amount of TV watched per head has not changed for 40 years. Preliminary findings from Project STIL suggest that inactivity is more complex that we sometimes think. Indeed, measures of 'couch potato-ism', such as TV viewing, may be inappropriate markers of inactivity.

Child↗
PubMed2004

Couch kids: correlates of television viewing among youth.

The purpose of this study was to review the published empirical correlates of television/video viewing among youth (2 to 18 years). A descriptive semi-quantitative review was conducted based on 68 primary studies. Variables consistently associated with TV/video viewing were ethnicity (non-white +), parent income (-), parent education (-), body weight (+), between meal snacking (+), number of parents in the house (-), parents TV viewing habits (+), weekend (+) and having a TV in the bedroom (+). Variables consistently unrelated to TV/video viewing were sex, other indicators of socio-economic status, body fatness, cholesterol levels, aerobic fitness, strength, other indicators of fitness, self-perceptions, emotional support, physical activity, other diet variables, and being an only child. Few modifiable correlates have been identified. Further research should aim to identify modifiable correlates of TV/video viewing if interventions are to be successfully tailored to reduce this aspect of inactivity among youth.

Adolescent↗
PubMed2004

Evaluation of a two-year middle-school physical education intervention: M-SPAN.

PURPOSE: School physical education (PE) is highly recommended as a means of promoting physical activity, and randomized studies of health-related PE interventions in middle schools have not been reported. We developed, implemented, and assessed an intervention to increase physical activity during middle-school PE classes. METHODS: Twenty-four middle schools (approximately 25,000 students, 45% nonwhite) in Southern California participated in a randomized trial. Schools were assigned to intervention (N = 12) or control (N = 12) conditions, and school was the unit of analysis. A major component of the intervention was a 2-yr PE program, which consisted of curricular materials, staff development, and on-site follow-up. Control schools continued usual programs. Student activity and lesson context were observed in 1849 PE lessons using a validated instrument during baseline and intervention years 1 and 2. RESULTS: The intervention significantly (P = 0.02) improved student moderate to vigorous physical activity (MVPA) in PE, by approximately 3 min per lesson. Effects were cumulative; by year 2 intervention schools increased MVPA by 18%. Effect sizes were greater for boys (d = 0.98; large) than girls (d = 0.68; medium). CONCLUSIONS: A standardized program increased MVPA in middle schools without requiring an increase in frequency or duration of PE lessons. Program components were well received by teachers and have the potential for generalization to other schools. Additional strategies may be needed for girls.

Adolescent↗
PubMed2003

Environmental interventions for eating and physical activity: a randomized controlled trial in middle schools.

BACKGROUND: Our objective was to evaluate the effects of environmental, policy, and social marketing interventions on physical activity and fat intake of middle school students on campus. DESIGN: Twenty-four middle schools were randomly assigned to intervention or control conditions. Baseline measures were collected in spring 1997, and interventions were conducted during the 1997-1998 and 1998-1999 school years SETTING/PARTICIPATION: The schools had mean enrollments of 1109, with 44.5% nonwhite students. Over 2 years, physical activity interventions were designed to increase physical activity in physical education classes and throughout the school day. Nutrition interventions were designed to provide and market low-fat foods at all school food sources, including cafeteria breakfasts and lunches, a la carte sources, school stores, and bag lunches. School staff and students were engaged in policy change efforts, but there was no classroom health education. MAIN OUTCOMES MEASURES: Primary outcomes were measured by direct observation and existing records. RESULTS: Randomized regression models (N =24 schools) revealed a significant intervention effect for physical activity for the total group (p <0.009) and boys (p <0.001), but not girls (p <0.40). The intervention was not effective for total fat (p <0.91) or saturated fat (p <0.79). Survey data indicated that the interventions reduced reported body mass index for boys (p <0.05). CONCLUSIONS: Environmental and policy interventions were effective in increasing physical activity at school among boys but not girls. The interventions were not effective in reducing fat intake at school. School environmental and policy interventions have the potential to improve health behavior of the student population, but barriers to full implementation need to be better understood and overcome.

Adolescent↗
PubMed2002

What do middle school children bring in their bag lunches?

BACKGROUND: Limited documentation exists on nutritional characteristics of bag lunches, although about 30% of adolescents take them. This study describes: (a) the prevalence of different types of foods in bag lunches, (b) the number of kilocalories, percentage of kilocalories from fat, amount of total fat, saturated fat, cholesterol, and sugar, and (c) the differences related to gender and grade. METHODS: In 24 middle schools, observations were made on 1,381 bag lunches (about 58 per school) during one semester. RESULTS: The most common bag lunch components were beverages and sandwiches. Fruits were more common than vegetables; non-chip snacks and chips were more common than cookies, candy, and cakes/pies. Bag lunches averaged 596.2 kcal (29.7% from fat), 20.8 g of total fat, 6.2 g of saturated fat, 32.6 mg of cholesterol, and 21.3 g of sugar. Boys' bag lunches had significantly more kilocalories, total fat, saturated fat, cholesterol, and percentage of energy from fat than girls' lunches. Significant grade differences were found only for total fat and cholesterol, with seventh graders bringing more than sixth graders. CONCLUSION: More research on the nutritional quality of foods brought to school in bag lunches is important for gaining a better understanding about how to improve students' nutrition.

Adolescent↗
PubMedDate not supplied

Short-term changes in sedentary behaviour during adolescence: Project STIL (Sedentary Teenagers and Inactive Lifestyles).

HYPOTHESIS: Changes in body composition and body image during puberty will impact on sedentary behavioural choices. AIM: The study aimed to investigate the effects of changes in pubertal status, body composition and body image on changes in time spent being sedentary. PARTICIPANTS AND METHODS: Eighty-three school students aged 10-15 years were studied at 6-month intervals. BMI and percentage body fat (%BF) were calculated from anthropometric measures. Sedentary behaviour and sleep time were computed for weekday and weekend days using momentary-time-sampling diaries. Body image was measured using the Physical Self-Perception Profile for Children. Pubertal status was assessed from self-reported secondary sexual characteristics. RESULTS: During weekdays, boys' sedentary behaviour increased by a significantly greater amount for those who increased pubertal level compared with those who did not. No significant correlations were found between changing pubertal status, body composition, and body image for either gender. For girls, but not boys, a significant amount of the variance of the change in weekend day sedentary behaviour was explained by changing %BF, independent of changing pubertal status. CONCLUSION: Only a part of the hypothesis was supported by these data. Changes in sedentary behaviour were not associated with behavioural choices triggered by body compositional changes.

Adolescent↗
PubMedDate not supplied

Tackling the obesity pandemic: a call for sedentary behaviour research.

An emerging threat to public health is seen in the dramatic rise in obesity status of Canadians, especially among young people. In addressing the possible factors responsible for these dramatic increases, this paper outlines the importance of understanding sedentariness as an important health behaviour, distinct from physical activity, and identifying the modifiable determinants of sedentary behaviours.

Adolescent↗