Physical activity, television viewing time and 12 year changes in waist circumference

PURPOSE: Both moderate-to-vigorous physical activity (MVPA) and sedentary behavior can be associated with adult adiposity. Much of the relevant evidence is from cross-sectional studies or from prospective studies with relevant exposure measures at a single time point prior to weight gain or incident obesity. This study examined whether changes in MVPA and television (TV) viewing time are associated with subsequent changes in waist circumference, using data from three separate observation points in a large population-based prospective study of Australian adults. METHODS: Data were obtained from the Australian Diabetes, Obesity and Lifestyle study collected in 1999-2000 (baseline), 2004-05 (Wave 2), and 2011-12 (Wave 3). The study sample consisted of adults aged 25 to 74 years at baseline who also attended site measurement at three time points (n=3261). Multilevel linear regression analysis examined associations of initial five-year changes in MVPA and TV viewing time (from baseline to Wave 2) with 12-year change in waist circumference (from baseline to Wave 3), adjusting for well-known confounders. RESULTS: As categorical predictors, increases in MVPA significantly attenuated increases in waist circumference (p for trend< 0.001). TV viewing time change was not significantly associated with changes in waist circumference (p for trend =0.06). Combined categories of MVPA and TV viewing time changes were predictive of waist circumference increases; compared to those who increased MVPA and reduced TV viewing time, those who reduced MVPA and increased TV viewing time had a 2cm greater increase in waist circumference (p=0.001). CONCLUSION: Decreasing MVPA emerged as a significant predictor of increases in waist circumference. Increasing TV viewing time was also influential, but its impact was much weaker than MVPA.This is an open-access article distributed under the terms of the Creative Commons Attribution-Non Commercial-No Derivatives License 4.0 (CCBY-NC-ND), where it is permissible to download and share the work provided it is properly cited. The work cannot be changed in any way or used commercially.

A qualitative study of environmental factors important for physical activity in rural adults

PURPOSE: Despite increasing evidence that the physical environment impacts on physical activity among urban-dwellers, little attention has been devoted to understanding this relationship in rural populations. Work in this area is further hindered by a lack of environmental measures specifically designed for rural settings. This qualitative study aimed to explore the salience of urban physical activity environment constructs among rural adults. METHODS: In 2011, 49 rural men and women from three distinct areas (coastal, animal-based farming, forestry/plant-based farming) of rural Tasmania, Australia, were purposively recruited to participate in semi-structured interviews. Interviews explored features of the built and social environment commonly examined in studies of urban adults, including functional characteristics (eg, lighting, footpaths, roads/verges), road and personal safety, availability and accessibility of places to be active, destinations, and aesthetics. Interviews were recorded, transcribed verbatim and analysed using a content-thematic approach using QSR NVivo software. FINDINGS: While some urban environmental constructs were salient to these rural adults, such as availability of and accessibility to places to be active, some constructs were operationalised differently, such as road safety (where large trucks and winding roads rather than traffic density was of concern), or were not considered relevant (eg, personal safety related to crime, availability of walkable destinations, aesthetics). CONCLUSIONS: The measurement of the physical environment in rural populations may require reconsideration and/or modification to ensure salience and appropriate quantification of associations with physical activity in future studies.

A machine learning approach to measure and monitor physical activity in children to help fight overweight and obesity

Physical Activity is important for maintaining healthy lifestyles. Recommendations for physical activity levels are issued by most governments as part of public health measures. As such, reliable measurement of physical activity for regulatory purposes is vital. This has lead research to explore standards for achieving this using wearable technology and artificial neural networks that produce classifications for specific physical activity events. Applied from a very early age, the ubiquitous capture of physical activity data using mobile and wearable technology may help us to understand how we can combat childhood obesity and the impact that this has in later life. A supervised machine learning approach is adopted in this paper that utilizes data obtained from accelerometer sensors worn by children in free-living environments. The paper presents a set of activities and features suitable for measuring physical activity and evaluates the use of a Multilayer Perceptron neural network to classify physical activities by activity type. A rigorous reproducible data science methodology is presented for subsequent use in physical activity research. Our results show that it was possible to obtain an overall accuracy of 96 % with 95 % for sensitivity, 99 % for specificity and a kappa value of 94 % when three and four feature combinations were used.

Validation of a computerized use of time recall for activity measurement in advanced-aged adults

BACKGROUND: The Multimedia Activity Recall for Children and Adults (MARCA) is a computerized recall instrument that records use of time during 24 hr the previous day and has been developed to address limitations of current self-report physical activity measures for those in advanced age. METHODS: Test-retest reliability and convergent validity of the adult MARCA were assessed in a sample of 45 advanced-age adults (age 84.9 SD ± 1.62 yr) as a subsample of the Life and Living in Advanced-Age Cohort Study New Zealand (LiLACS NZ). Test-retest methods required participants to recall the previous day's activity using the MARCA twice within the same day. Convergent validity was assessed against accelerometry. RESULTS: Test-retest reliability was high, with ICCs greater than .99 for moderate to vigorous physical activity (MVPA) and physical activity level (PAL). Compared with accelerometry, the MARCA demonstrated validity comparable to other self-report instruments with Spearman's coefficients of .34 and .59 for time spent in nonsedentary physical activity and PAL. CONCLUSION: The MARCA is a valid and reliable self-report tool for physical activity behaviors in advanced-age adults.

Measuring physical activity in a cardiac rehabilitation population using a smartphone-based questionnaire

BACKGROUND: Questionnaires are commonly used to assess physical activity in large population-based studies because of their low cost and convenience. Many self-report physical activity questionnaires have been shown to be valid and reliable measures, but they are subject to measurement errors and misreporting, often due to lengthy recall periods. Mobile phones offer a novel approach to measure self-reported physical activity on a daily basis and offer real-time data collection with the potential to enhance recall.

OBJECTIVE: The aims of this study were to determine the convergent validity of a mobile phone physical activity (MobilePAL) questionnaire against accelerometry in people with cardiovascular disease (CVD), and to compare how the MobilePAL questionnaire performed compared with the commonly used self-recall International Physical Activity Questionnaire (IPAQ).

METHODS: Thirty adults aged 49 to 85 years with CVD were recruited from a local exercise-based cardiac rehabilitation clinic in Auckland, New Zealand. All participants completed a demographics questionnaire and underwent a 6-minute walk test at the first visit. Subsequently, participants were temporarily provided a smartphone (with the MobilePAL questionnaire preloaded that asked 2 questions daily) and an accelerometer, which was to be worn for 7 days. After 1 week, a follow-up visit was completed during which the smartphone and accelerometer were returned, and participants completed the IPAQ.

RESULTS: Average daily physical activity level measured using the MobilePAL questionnaire showed moderate correlation (r=.45; P=.01) with daily activity counts per minute (Acc_CPM) and estimated metabolic equivalents (MET) (r=.45; P=.01) measured using the accelerometer. Both MobilePAL (beta=.42; P=.008) and age (beta=-.48, P=.002) were significantly associated with Acc_CPM (adjusted R(2)=.40). When IPAQ-derived energy expenditure, measured in MET-minutes per week (IPAQ_met), was considered in the predicted model, both IPAQ_met (beta=.51; P=.001) and age (beta=-.36; P=.016) made unique contributions (adjusted R(2)=.47, F2,27=13.58; P<.001).There was also a significant association between the MobilePAL and IPAQ measures (r=.49, beta=.51; P=.007).

CONCLUSIONS: A mobile phone-delivered questionnaire is a relatively reliable and valid measure of physical activity in a CVD cohort. Reliability and validity measures in the present study are comparable to existing self-report measures. Given their ubiquitous use, mobile phones may be an effective method for physical activity surveillance data collection.

Adolescent physical activity: does implementation intention have a role?

BACKGROUND: The current study tested the utility of an integrated social cognitive model to predict physical activity (PA) intentions and behavior in New Zealand adolescents. METHOD: Seventy-two adolescents (mean age = 16.92, SD = 0.66) completed measures consistent with the integrated model (attitude, subjective norm, perceived behavioral control [PBC], goal intention, task-efficacy, barrier efficacy, and implementation intention). Pedometer data (Yamax SW200 pedometer) were collected for 7 days, and a self-report 7-day recall questionnaire was administered at the end of this week. A series of hierarchical regression analyses were conducted to examine the contribution of the model to PA goal intention, implementation intention, self-reported and objective PA. RESULTS: The integrated model accounted for 41% of goal intention, 33% of implementation intention, and 41% and 18% of subjectively and objectively measured PA, respectively. PBC had the strongest association with goal intention whereas attitude had the strongest association with implementation intention. Task-efficacy made the greatest contribution to objectively measured PA, whereas implementation intention had the strongest association with subjectively measured PA. CONCLUSION: These findings have implications regarding PA measurement in adolescent populations, and suggest that social cognitive variables play an important role in adolescent PA. Recommendations for future research are discussed.

Correlates of agreement between accelerometry and self-reported physical activity

PURPOSE: Understanding factors that influence accurate assessment of physical activity (PA) and sedentary behavior (SB) is important to measurement development, epidemiologic studies, and interventions. This study examined agreement between self-reported (International Physical Activity Questionnaire-Long Form [IPAQ-LF]) and accelerometry-based estimates of PA and SB across six countries and identified correlates of between-method agreement. METHODS: Self-report and objective (accelerometry-based) PA and SB data were collected in 2002-2011 from 3865 adult participants in eight cities from six countries (Belgium, Czech Republic, Denmark, Spain, United Kingdom, and United States). Between-method relative agreement (correlation) and absolute disagreement (mean difference between conceptually and intensity-matched IPAQ-LF and accelerometry-based PA and SB variables) were estimated. Also, sociodemographic characteristics and PA patterns were examined as correlates of between-method agreement. RESULTS: Observed relative agreement (relationships of IPAQ-LF with accelerometry-based PA and SB variables) was small to moderate (r = 0.05-0.37) and was moderated by sociodemographic (age, sex, weight status, and education) and behavioral (PA-type) factors. The absolute disagreement was large, with participants self-reporting higher PA intensity and total time in moderate-to-vigorous-intensity PA than accelerometry. Also, self-reported sitting time was lower than accelerometry-based sedentary behavior. After adjusting for sociodemographic and behavioral factors, the absolute disagreement between pairs of IPAQ-LF and accelerometry-based PA variables remained significantly different across cities/countries. CONCLUSIONS: Present findings suggest systematic cultural and/or linguistic and sociodemographic differences in absolute agreement between the IPAQ-LF and the accelerometry-based PA and SB variables. These results have implications for the interpretation of international PA and SB data and correlate/determinant studies. They call for further efforts to improve such measures.

Workplace pedometer interventions for increasing physical activity

Background
The World Health Organization and the World Economic Forum have recommended further research to strengthen current knowledge of workplace health programmes, particularly on effectiveness and using simple instruments. A pedometer is one such simple instrument that can be incorporated in workplace interventions.

Objectives
To assess the effectiveness of pedometer interventions in the workplace for increasing physical activity and improving subsequent health outcomes.

Search methods
Electronic searches of the Cochrane Central Register of Controlled Trials (671 potential papers), MEDLINE (1001), Embase (965), CINAHL (1262), OSH UPDATE databases (75) and Web of Science (1154) from the earliest record to between 30th January and 6th February 2012 yielded 3248 unique records. Reference lists of articles yielded an additional 34 papers. Contact with individuals and organisations did not produce any further records.

Selection criteria
We included individual and cluster-randomised controlled trials of workplace health promotion interventions with a pedometer component in employed adults. The primary outcome was physical activity and was part of the eligibility criteria. We considered subsequent health outcomes, including adverse effects, as secondary outcomes.

Data collection and analysis
Two review authors undertook the screening of titles and abstracts and the full-text papers independently. Two review authors (RFP and MC) independently completed data extraction and risk of bias assessment. We contacted authors to obtain additional data and clarification.

Main results
We found four relevant studies providing data for 1809 employees, 60% of whom were allocated to the intervention group. All studies assessed outcomes immediately after the intervention had finished and the intervention duration varied between three to six months. All studies had usual treatment control conditions; however one study’s usual treatment was an alternative physical activity programme while the other three had minimally active controls. In general, there was high risk of bias mainly due to lack of blinding, self reported outcome measurement, incomplete outcome data due to attrition, and most of the studies had not published protocols, which increases the likelihood of selective reporting.

Three studies compared the pedometer programme to a minimally active control group, but the results for physical activity could not be combined because each study used a different measure of activity. One study observed an increase in physical activity under a pedometer programme, but the other two did not find a significant difference. For secondary outcomes we found improvements in body mass index, waist circumference, fasting plasma glucose, the quality of life mental component and worksite injury associated with the pedometer programmes, but these results were based on limited data from one or two small studies. There were no differences between the pedometer programme and the control group for blood pressure, a number of biochemical outcomes and the quality of life physical component. Sedentary behaviour and disease risk scores were not measured by any of the included studies.

One study compared a pedometer programme and an alternative physical activity programme, but baseline imbalances made it difficult to distinguish the true improvements associated with either programme.

Overall, there was insufficient evidence to assess the effectiveness of pedometer interventions in the workplace.

There is a need for more high quality randomised controlled trials to assess the effectiveness of pedometer interventions in the workplace for increasing physical activity and improving subsequent health outcomes. To improve the quality of the evidence available, future studies should be registered in an online trials register, publish a protocol, allocate time and financial support to reducing attrition, and try to blind personnel (especially those who undertake measurement). To better identify the effects of pedometer interventions, future studies should report a core set of outcomes (total physical activity in METs, total time sitting in hours and minutes, objectively measured cardiovascular disease and type II diabetes risk factors, quality of life and injury), assess outcomes in the long term and undertake subgroup analyses based upon demographic subgroups (e.g. age, gender, educational status). Future studies should also compare different types of active intervention to test specific intervention components (eligibility, duration, step goal, step diary, settings), and settings (occupation, intervention provider).

Authors’ conclusions
There was limited and low quality data providing insufficient evidence to assess the effectiveness of pedometer interventions in the workplace for increasing physical activity and improving subsequent health outcomes.

P L A I N  L A N G U A G E  S U M M A R Y

Do workplace pedometer interventions increase physical activity?
The World Health Organization recommends that most people should undertake at least 30 minutes of moderate-intensity physical activity on most days, as it reduces the risk of cardiovascular disease, diabetes and some cancers. However, less than 40% of the world’s population are undertaking adequate amounts of physical activity and rates have been declining. Here we assess whether pedometer workplace interventions increase physical activity and thereby lead to subsequent health benefits.

To assess this, we searched for randomised controlled trials of workplace health promotion interventions that involved the use of a pedometer undertaken in employed adults. Between 30th January and 6th February 2012 we searched a range of electronic libraries and references of relevant papers, retrieving 3282 potential papers.

We eventually included four studies in the review. One study compared pedometer programmes with an alternative physical activity programme, but there were important baseline differences between the intervention and control groups that made it difficult to distinguish the true effect. The three remaining studies compared pedometer programmes with minimally active control groups. One study observed an improvement in physical activity in the pedometer programme, but two other studies found no significant difference between the pedometer group and the control group. We could not combine these results together, as each study used a different measure for physical activity, so it is not clear what the overall effect is. Single studies found beneficial changes in body mass index, fasting plasma glucose, the mental component of quality of life and worksite injury associated with the pedometer programmes as opposed to the control group. However, none of the studies identified consistent differences between the pedometer programme and the control group for waist circumference, blood pressure and quality of life outcomes. In addition, we judged the majority of included studies to have a high risk of bias, mainly due to participants and staff knowing who was in the intervention and who was in the control group, attrition of participants and not having published a protocol prior to running the study.

We conclude that there was insufficient evidence to assess whether workplace pedometer interventions are of benefit. There is a need for further high quality randomised controlled trials to be undertaken with a range of health outcomes and assessment in the long term.

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.

Playing their part: the role of physical activity and sport in sustaining the health and well being of small rural communities

It is widely recognised that the health of rural Australians is poor in comparison with their urban counterparts. Similarly, the role played by physical activity in maintaining health has been well researched and is well documented. However, little appears to have been published in recent years about the links between physical activity and health in rural communities. The objective of this article was to begin to address that gap. To achieve this, the article drew on research conducted in two small rural communities in Victoria Australia, and highlighted the role that physical activity and sport played in sustaining the health and wellbeing of individuals and communities in rural areas. Taking the World Health Organisation's definition of health (a state of complete physical, mental and social well-being and not merely the absence of disease) as its measure, the paper highlighted the many ways in which physical activity and sport in rural communities contribute to physical health, mental wellbeing and social cohesiveness. Based this finding, the authors suggest that physical activity and sport make a significant contribution to the health and wellbeing of rural people and their communities and suggest that further research is necessary to better define this apparent contribution.

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.

Physical activity and sedentary behavior: a population-based study of barriers, enjoyment, and preference

The associations of physical activity and sedentary behavior with barriers, enjoyment, and preferences were examined in a population-based mail survey of 1,332 adults. Respondents reporting high enjoyment and preference for physical activity were more likely to report high levels of activity. Those reporting cost, the weather, and personal barriers to physical activity were less likely to be physically active. Preference for sedentary behavior was associated with the decreased likelihood of being physically active, and the weather as a barrier to physical activity was associated with the increased likelihood of sedentary behavior. These constructs can be used to examine individual and environmental influences on physical activity and sedentary behavior in specific populations and could inform the development of targeted interventions.

Too hot to trot? exploring potential links between climate change, physical activity and health

Based on an analysis of existing literature, this paper explores the links between climate change, physical activity and health. It highlights the importance of physical activity for health, explores current understandings of factors influencing participation in sport and physical activity, and develops some hypotheses about the ways in which climate change may impact on the factors influencing physical activity and thereby on the level of participation in physical activity. The paper argues that climate change has the potential to be a barrier to participation in physical activity, particularly in areas where temperatures are already relatively high, and that a reduction in physical activity across the population is likely to have detrimental health impacts. The need for research to clarify the nature and extent of the threat posed to physical activity participation is highlighted, as is the need to take into account the direct and indirect costs of any changes or reductions in physical activity in any assessment of the costs of climate change and/or its mitigation.

Do logbooks influence recall of physical activity in validation studies?

Purpose: To examine whether physical activity logbooks influence estimates of validity of 7-d recall physical activity questionnaires. Methods: A  convenience sample of 551 adults aged 18–75 yr wore an MTI  accelerometer for seven consecutive days and were then randomly administered two of four 7-d recall physical activity questionnaires that varied in length and format (Active Australia Survey (AAS), long and short  International Physical Activity Questionnaires (IPAQ-L and IPAQ-S), and Behavioral Risk Factor Surveillance System (BRFSS)). A subsample of 75% concurrently completed a physical activity logbook. Results: Correlations (rho) between self-reported and measured duration of moderate- and vigorous-intensity activity and total activity were similar among participants who received a logbook and those who did not for each of the four instruments. There was also no interaction between assessment method (survey, accelerometer) and the assignment of a logbook. For the IPAQ-L, however, variability in the difference between accelerometer data and responses to the vigorous items was smaller among those assigned a logbook (F = 4.128, df = 260, P = 0.043). Overall, there were no differences in percent agreement or kappa for participation in sufficient levels of physical activity according to receipt of a logbook for any of the surveys. Conclusion: The process of self-monitoring through completion of a logbook does not appear to influence estimates of validity for brief or long questionnaires with global questions. Whereas the magnitude of error in accuracy of recall of particular types of activity may be reduced by completion of a logbook that is similar in structure to the survey being validated, this does not appear to influence overall estimates of validity.