Associations of physical activity with body weight and fat in men and women

OBJECTIVE: Increasing physical activity is strongly advocated as a key public health strategy for weight gain prevention. We investigated associations of leisure-time physical activity (LTPA) and occupational/domestic physical activity with body mass index (BMI) and a skinfold-derived index of body fat (sum of six skinfolds), among normal-weight and overweight men and women.

DESIGN: Analyses of cross-sectional self-report and measured anthropometric data.

SUBJECTS: A total of 1302 men and women, aged 18-78 y, who were part of a randomly selected sample and who agreed to participate in a physical health assessment.

MEASUREMENTS: Self-report measures of physical activity, measured height and weight, and a skinfold-derived index of body fatness.

RESULTS: Higher levels of LTPA were positively associated with the likelihood of being in the normal BMI and lower body fat range for women, but few or no associations were found for men. No associations were found between measures of occupational/domestic activity and BMI or body fat for men or women.

CONCLUSION: By using a skinfold sum as a more direct measure of adiposity, this study extends and confirms the previous research that has shown an association between BMI and LTPA. Our results suggest gender differences in the relationship of leisure-time physical activity with body fatness. These findings, in conjunction with a better understanding of the causes of such differences, will have important public health implications for the development and targeting of weight gain prevention strategies.

Changes to (primary) school recess and their effect on children's physical activity: an Australian perspective

Headlines greet us on almost a daily basis lamenting the declining health of Australian children. They are said to be inactive, unfit, overweight and lacking in fundamental motor skills. It is a disturbing picture. Calls have gone out to parents to encourage their children to be more active and for schools to counter these problems by allocating more time to sport and physical education however, in both instances, there are particular problems to be addressed. One aspect of schooling that is rarely considered in discussions about how to increase children's activity levels is recess. This article examines the problems facing physical education and offers some suggestions as to how schools might preserve and promote physical activity during recess breaks.

Validity and reliability of a physical activity recall instrument among overweight and non-overweight men and women

This study examined the validity and reliability of survey items measuring one-week recall of physical activity (PA) and examined differences by weight status. A sub-aim of the study was to objectively assess the intensity of activity that most closely matches self-report. A questionnaire was administered to adults twice, three days apart. It was again administered after subjects wore a MTI/CSA accelerometer for seven days (n = 118). Several metabolic equivalent (MET) thresholds were applied to the accelerometer data. Agreement between test and re- test estimates of sufficient physical activity for health benefits (150 min/week) was high (% agreement > 90%). Correlations (rho) between total reported PA (mins/day) and accelerometer data were 0.29 (p < 0.05) among men and 0.25 (p < 0.05) among women. Among men, self- reported duration of moderate PA (3-5.9 METS) and accelerometer data were significantly correlated (rho = 0.40, p < 0.01), with no differences by weight status. Among women, a significant relationship was found only for those who were not overweight (rho = 0.52, p < 0.001). A significant correlation between self-reported duration of vigorous PA (6+ METS) and accelerometer data was only found for overweight men (rho = 0.40, p < 0.05). When lower MET thresholds were applied to the accelerometer data, women's reported duration of moderate-intensity PA was most strongly correlated with moderate PA (accelerometer) defined as 2.0-5.9 METS (rho = 0.39, p < 0.01). The recall instrument provides a consistent measure of physical activity and validation coefficients were similar to those obtained for other physical activity recall questionnaires. However, the ability to measure PA by self-report may vary by weight status.

Evidence-based strategies to promote physical activity among children, adolescents and young adults: review and update

This paper updates evidence reviewed in the first edition of Getting Australia Active on effective physical activity (PA) intervention strategies among children, adolescents and young adults. Intervention studies published between 1999 and September 2003 were identified using electronic databases and hand searching. A total of 28 discrete studies were identified (31 papers). Six of nine studies reported significant effects on child or youth PA in school settings. Those that incorporated whole-of-school approaches including curriculum, policy and environmental strategies appeared to be more effective than those that incorporated curriculum-only approaches. Five of 10 studies with children and two of five studies with adolescents reported increased PA or decreased sedentary behaviour in other settings. Interventions that included contact with families generally appeared to be most effective. One study with adolescents provided some evidence of the potential effectiveness of interventions based in primary care. Two of four papers reported modest short-term results among young adults, including increased PA stage of change or a higher likelihood of being adequately physically active, but none showed any evidence of sustained increases in PA. There is an urgent need for additional studies examining interventions aimed at young adults. Across the three life stages, future studies should include objective PA measures, longer-term follow-up, larger sample sizes, a specific focus on PA (rather than weight) and culturally-specific strategies that build evidence in Australian populations. Future studies should target high risk groups and a broad range of settings and strategies focusing on reducing sedentary behaviours as well as increasing PA.

How feasible are healthy eating and physical activity for young women?

Objective: This study investigated young women’s perceptions of the feasibility of physical activity and healthy eating behaviours, and how these vary by socioeconomic status, domestic characteristics and weight status. Design: This population-based study used a mailed questionnaire to investigate perceptions of the feasibility of commonly recommended healthy eating and physical activity behaviours among a sample of young women. The feasibility of 29 physical activity behaviours (e.g. relating to frequency, intensity, duration, domain/setting) and 15 healthy eating behaviours (e.g. relating to location/setting, fruit and vegetable intake, fat/sugar intake) was assessed. Height, weight and sociodemographic details were also obtained. Setting: Nation-wide community-based survey. Subjects: A total of 445 women aged 18–32 years selected randomly from the Australian electoral roll. Results: Most women reported that they either were already engaged in many of the healthy eating behaviours or saw these as highly feasible. Many physical activity behaviours, on the other hand, were perceived as less feasible, particularly among women with children and women who were overweight. Conclusions: Health promotion messages and strategies aimed at increasing physical activity and healthy eating are unlikely to succeed unless they take into account perceptions that these behaviours are not feasible. For young women, this may involve promoting more time-effective, flexible ways of achieving recommended physical activity. Messages specifically targeted to women with children, and women who are overweight, are required.

Piloting the feasibility and effectiveness of print- and telephone-mediated interventions for promoting the adoption of physical activity in Australian adults

This study examined the feasibility and effectiveness for increasing physical activity of a print-based intervention, and a print- plus telephone-mediated intervention among mid-life and older Australian adults. A randomised controlled trial study design was used. In mid-2002, 66 adults (18 men, 48 women) aged 45–78 years, who identified themselves as underactive, were recruited through advertisements and word-of-mouth at two sites (Melbourne and Brisbane), and randomised to either the print or print-plus-telephone mediated intervention group. Participants in both groups attended an initial briefing session, and over the 12-week intervention period received an instructional newsletter and use of a pedometer (both groups), and individualised telephone calls (print-plus-telephone group only). Self-reported physical activity data were collected at baseline, 12 and 16 weeks. Measures of self-reported global physical activity, moderate-vigorous intensity activity and walking all showed increases between baseline and 12 weeks for both intervention groups. These increases were generally maintained by 16 weeks, although participants in the print-plus-telephone group maintained slightly higher levels of global reported activity and walking (by approximately 30 mins/wk) than those in the print group. These interventions show potential for promoting initial increases in physical activity among mid-life and older Australian adults, and should be evaluated across more extended time periods.

Association of family environment with children's television viewing and with low level of physical activity

Objective: This study examined associations between the family environment and children's television (TV) viewing and likelihood of being low-active.
Research Methods and Procedures: In 2001, children were recruited from 19 primary schools in Melbourne, Australia. Parents completed a questionnaire about their child's TV viewing and the family environment. Children also completed a questionnaire and wore an accelerometer for 8 days. Movement counts were used to identify low-active children (lowest quartile). Data were analyzed in May 2004.
Results: The sample consisted of 878 children (mean age = 11.5 0.6 yrs). Multiple logistic regression revealed that socioeconomic status [adjusted odds ratios (AOR) = 0.4 boys], frequency families watched TV together (AOR = 2.0 boys), mothers' (AOR = 1.8 boys; AOR = 2.5 girls) and fathers' (AOR = 2.6 boys; AOR = 2.8 girls) TV viewing, and rules prohibiting TV during mealtimes (AOR = 0.6 boys; AOR = 0.6 girls) related to children watching TV 2 h/d. Variables associated with low-level physical activity included self-reported enjoyment of Internet use (AOR = 1.7 boys) and preference for watching TV (AOR = 2.3 girls), perception that mother uses computer a lot (AOR = 1.9 boys) and likes using the computer (AOR = 0.6 girls), fathers' reported computer/electronic games use (AOR = 1.7 girls), frequency families used computer together (AOR = 0.4 girls), rules that TV viewing must be supervised (AOR = 1.9 boys; AOR = 0.6 girls), and having pay TV (AOR = 0.6 boys) and electronic games at home (AOR = 2.6 boys).
Discussion: These findings suggest that the relationships between the family environment and TV viewing and low-level activity are complex and that these behaviors are distinct.

Trends in children`s physical activity and weight status in high and low socio-economic status areas of Melbourne, Victoria, 1985-2001

Objective:
To examine trends in active transport to and from school, in school sport and physical education (PE), and in weight status among children from high and low socio-economic status (SES) areas in Melbourne, Victoria, between 1985 and 2001.

Methods:
Cross-sectional survey data and measured height and weight from 1985 (n=557) and 2001 (n=926) were compared for children aged between 9–13 years within high and low SES areas.

Results:
From 1985 to 2001, the frequency of walking to or from school declined (4.38±4.3 vs. 3.61 ± 3.8 trips/wk, p<0.001), cycling to or from school also declined (1.22±2.9 vs. 0.36±1.5 trips/wk, p<0.001), and the frequency of PE lessons declined (1.64±1.1 vs. 1.18±0.9 lessons/wk, p<0.001). However, the frequency of school sport increased (0.9±1.22 vs. 1.24±0.8 sessions/wk, p<0.001). In 1985, 11.7% of children were overweight or obese compared with 28.7% in 2001 (p<0.001). Apart from walking to school and school sport, there were greater relative declines in cycling to school and PE, and increases in overweight and obesity among children attending schools in low SES areas compared with those attending schools in high SES areas.

Conclusions:
Declines in active school transport and PE have occurred at the same time as increases in overweight and obesity among Australian children.

Implications:
Promoting active school transport and maintaining school sport and PE should be important public health priorities in Australia. Current inequities in school sport and PE and in prevalence of overweight and obesity by area-level SES also need to be addressed.

Children's television viewing and objectively measured physical activity: associations with family circumstances

Background: The contribution of family circumstance to physical activity and television viewing has not been widely investigated in pre-adolescents, and available information is inconsistent. This study examines whether television viewing and objectively measured physical activity vary by different indicators of family circumstance.
Methods: Data from the 2001 Children's Leisure Activity Study and the 2002/3 Health, Eating and Play Study, involving Australian children in Grades Prep (mean age 6y) and 5–6 (mean age 11y), were combined. Children wore accelerometers for six consecutive 24 hour periods. Average min/day in low-intensity activity (1.0–1.9 METs) and moderate-to-vigorous-intensity activity (≥3 METs) were calculated. Parents reported children's television viewing and family circumstance. Linear regression analyses were conducted separately for young girls, young boys, older girls and older boys. Results: Complete data were available for 2458 children. Parental education and, to a lesser extent, employment level were inversely associated with television viewing. Children in single-parent families, those whose fathers were not in paid employment, and those without siblings tended to spend more time in low-intensity activity than their peers. Children with siblings spent more time in moderate-to-vigorous-intensity activity; associations were stronger for girls. Maternal education was positively associated with moderate-to-vigorous-intensity activity for younger children. Maternal employment was positively associated with moderate-to-vigorous-intensity activity for older children. Multivariable models did not demonstrate a cumulative explanatory effect.
Conclusion:  Individual measures of family circumstance were differentially associated with television, low-intensity activity and moderate-to-vigorous-intensity activity and associations were often not consistent across age-by-gender groups. Interventions may need to be tailored accordingly.

How can socio-economic differences in physical activity among women be explained? A qualitative study

This qualitative study investigated why women of low socio-economic status (SES) are less physically active than women of higher-SES. Semi-structured interviews were conducted with 19 high-, 19 mid- and 18 low-SES women. A social-ecological framework, taking into account intrapersonal, social and environmental level influences, was adopted to guide the development of interview questions and interpretation of data. Thematic analysis identified a number of key influences on physical activity that varied by SES. These included negative early life/family physical activity experiences (a consistent theme among those of low-/mid-SES); participation in a wider range of physical activities in leisure time (high-SES); greater priority given to television viewing (low-SES); lack of time due to work commitments (low-SES); lack of time due to family commitments (high-SES); and neighbourhood-level barriers (low-SES). Financial costs were not perceived as a key barrier by women in any SES group. Public health strategies aimed at reducing SES

Reliability of moderate-intensity and vigorous physical activity stage of change measures for young adults.

Background
The purpose of this study was to examine the reliability of stage of change (SOC) measures for moderate-intensity and vigorous physical activity in two separate samples of young adults. Staging measures have focused on vigorous exercise, but current public health guidelines emphasize moderate-intensity activity.
Method
For college students in the USA (n = 105) and in Australia (n = 123), SOC was assessed separately on two occasions for moderate-intensity activity and for vigorous activity. Test–retest repeatability was determined, using Cohen’s kappa coefficient.
Results
In both samples, the reliability scores for the moderate-intensity physical activity staging measure were lower than the scores for the vigorous exercise staging measure. Weighted kappa values for the moderate-intensity staging measure were in the “fair to good” range for both studies (0.50 and 0.45); for the vigorous staging measure kappa values were “excellent” and “fair to good” (0.76 and 0.72).
Conclusions
There is a need to standardize and improve methods for staging moderate-intensity activity, given that such measures are used in public health interventions targeting HEPA (health-enhancing physical activity).

Age-related differences in physical activity levels of young adults.

Purpose: To examine age-related differences in the physical activity behaviors of young adults.

Methods: We examined rates of participation in vigorous- and moderate-intensity leisure-time activity and walking, as well as an index of physical activity sufficient for health benefits in three Australian cross-sectional samples, for the age ranges of 18–19, 20–24, and 25–29 yr. Data were collected in 1991, 1996, and 1997/8.

Results: There was at least a 15% difference in vigorous-intensity leisure-time physical activity from the 18–19 yr to the 25–29 yr age groups, and at least a 10% difference in moderate-intensity leisure-time physical activity. For the index of sufficient activity there was a difference between 9 and 21% across age groups. Differences in rates of walking were less than 8%. For all age groups, males had higher rates of participation for vigorous and moderate-intensity activity than did females, but females had much higher rates of participation in walking than males. Age-associated differences in activity levels were more apparent for males.

Conclusions: Promoting walking and various forms of moderate-intensity physical activities to young adult males, and encouraging young adult females to adopt other forms of moderate-intensity activity to complement walking may help to ameliorate decreases in physical activity over the adult lifespan.

Developing national physical activity guidelines for Australians

The process and outcome of developing National Physical Activity Guidelines for Australians is described. The guidelines provide a means of incorporating new data on physical activity into public health education.

Understanding physical activity environmental correlates : increased specificity for ecological models

Ecological models are now used to understand the complex array of factors that influence physical activity, resulting in a greater emphasis on environmental correlates. This selective review examines whether the predictive capacity of these models could be improved if behavior-specific measures of the environment were used to predict context-specific behaviors.

Migrants getting fat in Australia: acculturation and its effects on the nutrition and physical activity of African migrants to developed countries

Obesity is a significant health problem in Australia and other developed countries and acculturation is one fo the many risk factors. This new book summarizes acculturation and anthropometric outcomes among sub-Saharan African migrants in Australia. The book further examines the relationship between acculturation and food, energy and nutrient intake and physical activity. Some policy recommendations are proposed.