Prospective study of physical activity and depressive symptoms in middle-aged women

Background: Although many studies support an inverse association between physical activity (PA) and depressive symptoms, prospective relationships between these variables have been confounded by pre-existing psychological and physical health problems. Methods: This study examined the dose-response relationships between self-reported PA and depressive symptoms, using cross-sectional and prospective data from a population-based cohort of middle-aged women who participated in the Australian Longitudinal Study on Women's Health (ALSWH) between 1996 and 2001. Participants completed three mailed surveys (SI, 1996; S2, 1998; S3, 2001), which included questions about time spent in walking, moderate- and vigorous-intensity PA, and measures of psychological health (Center for Epidemiologic Studies Depression scale [CESD-10], and Mental health [MH] subscale of the Short Form 36 survey). Relationships between previous (SI, S2), current (S3), and habitual (S1, S2, S3) PA and depressive symptoms were examined, adjusting for sociodemographic and health-related variables (n = 9207). Results: Mean CESD-10 scores decreased, and MH scores increased with increasing levels of previous, current, and habitual activity. Odds ratios for CESD-10 scores >= 10 or MH scores = 60 minutes of moderate-intensity PA per week, compared with those who reported less PA than this. Women who were in the lowest PA category at SI, but who subsequently reported >= 240 metabolic equivalent minutes (MET.mins) per week had lower odds of CESD-10 scores of >= 10 or MH scores

Prospective study of individual, social, and environmental predictors of physical activity: women's leisure running

Background: Understanding and influencing the determinants of physical activity is an important public health challenge. We used prospective data to examine the influence of individual, social, and environmental factors on physical activity behaviour, using regular running as the behavioural model. Methods: Over 500 middle-aged women completed two consecutive questionnaires in 2000 and 2002. Logistic regression analyses were used to examine factors predicting adoption of and regression from regular leisure-time running during the follow-up. Results: Women who frequently used behavioural change skills were more likely to adopt regular running (OR=4.0, CI=1.7-9.5). There was an interaction between the enjoyment of running and family support: those who rated enjoyment of running high and reported high family support were less likely to adopt running (OR= 0.2, CI = 0.1-0.5). Women who reported infrequent use of motives were more likely (OR = 3.3, CI = 1.6-6.9) to regress from regular running. There was an interaction between perceived health and the neighbourhood environment: those who perceived themselves to be in poor health and had an unattractive neighbourhood were more likely (OR = 2.7, CI = 0.9-8.3) to regress from regular running. Conclusions: Behavioural skills and enjoyment may be of particular importance for the adoption of regular activity; social support and an aesthetically attractive neighbourhood are likely to have a key role in encouraging maintenance. (c) 2004 Elsevier Ltd. All rights reserved.

The effect of weightbearing exercise with low frequency, whole body vibration on lumbosacral proprioception: A pilot study on normal subjects

Patients with low back pain (LBP) often present with impaired proprioception of the lumbopelvic region. For this reason, proprioception training usually forms part of the rehabilitation protocols. New exercise equipment that produces whole body, low frequency vibration (WBV) has been developed to improve muscle function, and reportedly improves proprioception. The aim of this pilot study was to investigate whether weightbearing exercise given in conjunction with WBV would affect lumbosacral position sense in healthy individuals. For this purpose, twenty-five young individuals with no LBP were assigned randomly to an experimental or control group. The experimental group received WBV for five minutes while holding a static, semi-squat position. The control group adopted the same weightbearing position for equal time but received no vibration. A two-dimensional motion analysis system measured the repositioning accuracy of pelvic tilting in standing. The experimental (WBV) group demonstrated a significant improvement in repositioning accuracy over time (mean 0.78 degrees) representing 39% improvement. It was concluded that WBV may induce improvements in lumbosacral repositioning accuracy when combined with a weightbearing exercise. Future studies with WBV should focus on evaluating its effects with different types of exercise, the exercise time needed for optimal outcomes, and the effects on proprioception deficits in LBP patients.

Emerging adulthood and patterns of physical activity among young Australian women

The transition from adolescence to young adulthood is associated with a sharp decline in physical activity, particularly for women. This article explores the relations between physical activity status and change and status and change in four life domains: residential independence, employment status, relationship status, and motherhood. Two waves of survey data from a representative sample of 8,545 Australian women, aged 18-23 at Survey 1 and 22-27 at Survey 2, were analyzed. Cross-sectionally, physical inactivity was most strongly related to being a mother married, and not being in the labor force. Longitudinally, decreases in physical activity were most strongly associated with moving into a live-in relationship, with getting married, and with becoming a mother When considered in combination, women who were married with children and not employed outside the home were the most likely to be physically inactive. The data suggest that adoption of adult statuses, particularly traditional roles involving family relationships and motherhood, is associated with reductions in physical activity for these women, although it is possible that the effect is driven by socioeconomic factors associated with early transitions. The data suggest a need for interventions to promote continued physical activity among young women who cohabit or marry and among those not in the workforce, in addition to those supporting young mothers to be physically active.

Individual or population approaches to the promotion of physical activity... is that the question?

A recent editorial raised several issues about the role of exercise physiologists in the fight against physical inactivity in Australia. This opinion piece argues that we must strive to work together in multidisciplinary groups to improve our understanding of the mechanisms which link PA and health and the ways to persuade people to become more active. Prescription of specific exercise programs supported by exercise physiologists is one strategy for helping to activate Australians, but it is unlikely that that this atone will have a significant impact on population health. If we are to activate the 10,000,000 Australians who are currently insufficiently active for health benefit, we will need the combined efforts of governments, NGOs, teachers, planners, marketing experts, veterinarians, and ALL our health professionals, to combine forces to activate Australia. (c) 2006 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved.

What does the animal model teach us about the effects of physical activity on growing bone?

Experiments to design physical activity programs that optimize their osteogenic potential are difficult to accomplish in humans. The aim of this article is to review the contributions that animal studies have made to knowledge of the loading conditions that are osteogenic to the skeleton during growth, as well as to consider to what extent animal studies fail to provide valid models of physical activity and skeletal maturation. Controlled loading studies demonstrate that static loads are ineffective, and that bone formation is threshold driven and dependent on strain rate, amplitude, and duration of loading. Only a few loading cycles per session are required, and distributed bouts are more osteogenic than sessions of long duration. Finally, animal models fail to inform us of the most appropriate ways to account for the variations in biological maturation that occur in our studies of children and adolescents, requiring the use of techniques for studying human growth and development.

Beneficial associations of physical activity with 2-h but not fasting blood glucose in Australian adults

OBJECTIVE - We examined the associations of physical activity with fasting plasma glucose (FPG) and with 2-h postload plasma glucose (2-h PG) in men and women with low, moderate, and high waist circumference. RESEARCH DESIGN AND METHODS - The Australian Diabetes, Obesity and Lifestyle (AusDiab) study provided data on a population-based cross-sectional sample of 4,108 men and 5,106 women aged >= 25 years without known diabetes or health conditions that could affect physical activity. FPG and 2-h PG were obtained from an oral glucose tolerance test. Self-reported physical activity level was defined according to the current public health guidelines as active (>= 150 min/week across five or more sessions) or inactive (< 150 min/week and/or less than five sessions). Sex-specific quintiles of physical activity time were used to ascertain dose response. RESULTS - Being physically active and total physical activity time were independently and negatively associated with 2-h PG. When physical activity level was considered within each waist circumference category, 2-h PG was significantly lower in active high-waist circumference women (beta-0.30 [95% CI -0.59 to -0.01], P = 0.044) and active low-waist circumference men(beta-0.25 [-0.49 to -0.02],P = 0.036) compared with their inactive counterparts. Considered across physical activity and waist circumference categories, 2-h PG levels were not significantly different between active moderate-waist circumference participants and active low-waist circumference participants. Associations between physical activity and FPG were nonsignificant. CONCLUSIONS - There are important differences between 2-h PG and FPG related to physical activity. It appears that 2-h PG is more sensitive to the beneficial effects of physical activity, and these benefits occur across the waist circumference spectrum.

The handbook of physical education

What is the current condition of the field of physical education? How has it adapted to the rise of kinesiology, sport and exercise science and human movement studies over the last thirty years? This Handbook provides an authoritative critical overview of the field and identifies future challenges and directions. The Handbook is divided in to six parts: - Perspectives and Paradigms in Physical Education Pedagogy Research; - Cross-disciplinary Contributions to Research on Physical Education; - Learners and Learning in Physical Education; - Teachers, Teaching and Teacher Education in Physical Education; - Physical Education Curriculum; - Difference and Diversity in Physical Education. This benchmark work is essential reading for educators and students in the field of physical education.

The place and meaning of physical activity, physical education, and physical culture in the lives of young people living in rural Queensland

Young people living in rural and regional areas are often reported as being less physically active than are young people living elsewhere. An understanding of this phenomenon will inform policies and strategies to address this finding. One source of valuable information is a qualitative understanding of how social relations and cultural meanings influence young people's opportunities and choices in relation to physical activity as told by young people themselves. The study reported here forms a component of a national project to gain insights into young people's engagement with physical activity and physical culture. Data has been collected for over two years with 15 young people residing in rural areas throughout Queensland, using semi- structured interviews. This paper reports the findings of the research. [Author abstract, ed]

Comparisons of physical separation methods of Kunjin virus-induced membranes

The two sets of connected membranes induced in Kunjin virus-infected cells are characterized by the presence of NS3 helicase/protease in both, and by RNA-dependent RNA polymerase (RdRp) activity plus the associated double-stranded RNA (dsRNA) template in vesicle packets (VP), or by the absence of both the VP-specific markers in the convoluted membranes/paracrystalline arrays (CM/PC). Attempts were made to separate flavivirus-induced membranes by sedimentation or flotation analyses in density gradients of sucrose or iodixanol, respectively, after treatment of cell lysates by sonication, osmotic shock, or tryptic digestion. Only osmotic shock treatment provided suggestive evidence of separation. This was explored by flow cytometry analysis (FCA) of RdRp active membrane fractions from a sucrose gradient, using dual fluorescent labelling via antibodies to NS3 and dsRNA. FCA revealed the presence of a dual labelled membrane population indicative of VP, and in a faster sedimenting fraction a membrane population able to be labelled only in NS3, representative of CM/PC and associated (R)ER. It was postulated that osmotic shock ruptured the bounding membrane of the VP, releasing the enclosed small vesicles associated with the Kunjin virus replication complex characterized previously. Notably, the presence of the full spectrum of nonstructural proteins in some membrane fractions was not a reliable marker for RdRp activity. These experiments may provide the opportunity for isolation of relatively pure flavivirus replication complexes in their native membrane-associated state by fluorescence-activated cell sorting. (C) 2004 Elsevier B.V. All rights reserved.

Levels of physical activity for colon cancer prevention compared with generic public health recommendations: Population prevalence and sociodemographic correlates

Background: The proportion of Australian adults achieving physical activity levels believed to be sufficient for colon cancer prevention was estimated, and sociodemographic correlates (age, gender, educational attainment, occupation, marital status, and children in household) of meeting these levels of activity were analyzed. Methods: Data from the 2000 National Physical Activity Survey were used to estimate the prevalence of participation in physical activity in relation to three criteria: generic public health recommendations, weekly amount of at least moderate-intensity physical activity currently believed to reduce risk of colon cancer, and weekly amount of vigorous-intensity physical activity believed to reduce risk of colon cancer. Results: Overall, 46% of adults met the generic public health criterion, 26% met the colon cancer criterion based on participation in at least moderate-intensity physical activity, and 10% met the colon cancer criterion based on vigorous-intensity physical activity. Women were less likely than men to meet the colon cancer criteria. Younger and more educated persons were more likely to meet all three criteria. The most pronounced differences between gender, age, and educational attainment groups were found for meeting the amount of vigorous-intensity physical activity believed to reduce risk of colon cancer. Conclusions: The population prevalence for meeting proposed physical activity criteria for colon cancer prevention is low and much lower than that related to the more generic public health recommendations. If further epidemiologic studies confirm that high volumes and intensities of activity are required, the public health challenges for colon cancer will be significant.

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 under-active, 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.