Kenneth R. Fox

Background. Many studies have shown that low levels of exercise in later life are associated with the progression of difficulties with activities of dai

The preventive effect of late-life physical exercise on cognitive deterioration has been reported in many cohort studies. However, the effect of exercise, independent of other cognitively demanding and social activities, is equivocal and little is known about the relative contributions of frequency, intensity, and duration of exercise. This study aimed to examine the relationships of exercise and its underlying components with cognitive function and rate of cognitive change over an 8-year period in a nationally representative sample of older Taiwanese. Data from the 1999, 2003, and 2007 phases of the nationwide longitudinal survey were used. Data from a fixed cohort of 1,268 participants aged 70 years or older in 1999 with 8 years of follow-up were analyzed. Cognitive function was assessed using the Short Portable Mental Status Questionnaire. Self-reported frequency, intensity, and duration of exercise were collected. A generalized estimating equation with multivariate adjustment for sociodemographic variables, cognitive and social leisure activities, lifestyle behaviors, and health status was calculated. Participants who were physically active during leisure time had better subsequent cognitive function (incident rate ratios [IRR] = 0.63; 95 % CI, 0.54–0.75) and a slower rate of cognitive decline (p = 0.01). Among the components of exercise, only duration emerged as a predictor of cognitive function (p = 0.01). Older adults engaging in exercise for at least 30 min or more per session are likely to reduce the risk of subsequent cognitive decline. This research supports the case for physical exercise programs for older adults in order to help prevent loss of cognitive function.

Physical activity has many positive effects on children's health while TV viewing has been associated with adverse health outcomes. Many children do not meet physical activity recommendations and exceed TV viewing guidelines. Parents are likely to be an important influence on their children's behaviour. There is an absence of information about the associations between parents' and children's physical activity and TV viewing. Year 6 children and their parent were recruited from 40 primary schools. Results are presented for the 340 parent-child dyads with accelerometer data that met a ≥ 3 day inclusion criteria and the 431 parent-child dyads with complete self-reported TV viewing. Over 80% of the dyads with valid TV viewing data included mothers and their child. Mean minutes of moderate to vigorous physical activity (MVPA), minutes of sedentary time per day and counts per minute were assessed by accelerometer. Self-reported hours of TV viewing were coded into 3 groups (< 2 hours per day, 2-4 hours per day and >4 hours per day. Linear and multi-nominal regression models were run by child gender to examine parent-child associations. In linear regression models there was an association for the overall sedentary time of girls and their parents (t = 2.04. p = .020) but there was no association between girls' and parents' physical activity. There were no associations between parents' and boys' sedentary or physical activity time. For girls, the risk of watching more than 4 hours of TV per day, (reference = 2 hours of TV per day), was 3.67 times higher if the girl's parent watched 2-4 hours of TV per day (p = 0.037). For boys, the risk of watching more than 4 hours of TV per day, was 10.47 times higher if the boy's parent watched more than 4 hours of TV per day (p = 0.038). There are associations in the sedentary time of parents and daughters. Higher parental TV viewing was associated with an increased risk of high levels of TV viewing for both boys and girls. There were no associations between the time that parents and children spend engaged in physical activity.

Targeted interventions may be more effective at increasing children's physical activity. The aim of this study was to identify clusters of children based on physical activity and sedentary patterns across the week. Participants were 761, 10-11 year old children. Participants self-reported time spent in eight physical activity and sedentary contexts and wore an accelerometer. Cluster analysis was conducted on the time spent in the self-reported physical activity and sedentary contexts. Mean minutes of accelerometer derived of moderate to vigorous physical activity (MVPA) and sedentary time were derived for the entire week, weekdays only, weekend days and four different time periods across each type (weekend or weekday) of days. Differences in the physical activity patterns of the groups derived from the cluster analysis were assessed for overall physical activity as well as for the four time periods on weekdays and weekend days. Three clusters emerged: 1) High active/Low sedentary; 2) Low active/Moderate sedentary; and 3) High Active/High sedentary. Patterns of activity differed across the week for each group and the High Active/High sedentary obtained the most minutes of MVPA. Patterns of physical activity and sedentary time differed across the week for each cluster. Interventions could be targeted to the key periods when each group is inactive.

Many children do not meet physical activity guidelines. Parents and friends are likely to influence children's physical activity but there is a shortage of measures that are able to capture these influences. A new questionnaire with the following three scales was developed: 1) Parental influence on physical activity; 2) Motives for activity with friends scale; and 3) Physical activity and sedentary group normative values. Content for each scale was informed by qualitative work. One hundred and seventy three, 10-11 year old children completed the new questionnaire twice, one week apart. Participants also wore an accelerometer for 5 days and mean minutes of moderate to vigorous physical activity, light physical activity and sedentary time per day were obtained. Test-retest reliability of the items was calculated and Principal Component analysis of the scales performed and sub-scales produced. Alphas were calculated for main scales and sub-scales. Correlations were calculated among sub-scales. Correlations between each sub-scale and accelerometer physical activity variables were calculated for all participants and stratified by sex. The Parental influence scale yielded four factors which accounted for 67.5% of the variance in the items and had good (α > 0.7) internal consistency. The Motives for physical activity scale yielded four factors that accounted for 66.1% and had good internal consistency. The Physical activity norms scale yielded 4 factors that accounted for 67.4% of the variance, with good internal consistency for the sub-scales and alpha of .642 for the overall scale. Associations between the sub-scales and physical activity differed by sex. Although only 6 of the 11 sub-scales were significantly correlated with physical activity there were a number of associations that were positively correlated >0.15 indicating that these factors may contribute to the explanation of children's physical activity. Three scales that assess how parents, friends and group normative values may be associated with children's physical activity have been shown to be reliable and internally consistent. Examination of the extent to which these new scales improve our understanding of children's physical activity in datasets with a range of participant and family characteristics is needed.

Many youth physical activity interventions have minimal effect. To design better interventions we need to understand more about the factors that influence youth activity. Application of self-determination theory to youth physical activity, particularly the relatedness and competence, might suggest that friends and friendship groups influence the initiation and maintenance of youth physical activity. In this study we examined this issue. Seventeen focus groups were conducted with 113, 10–11 year old children, from 11 primary schools in Bristol, UK. Focus groups examined: 1) the nature of children's friendship groups; 2) associations between physical activity and social group status; and 3) how friendship groups affect the initiation and maintenance of physical activity. All focus groups were audio-taped and transcribed verbatim. Data were analyzed using content analysis. Participants reported that there were three different types of friendship groups; School friends; Neighborhood friends; and Other Friends who were friends from organized activities or children of their parents' friends. Participants had multiple groups of friends and engaged in different activities with the different groups. Possessing several groups of friends was desirable as it kept the friendships fresh and interesting. Physical activity was perceived as a positive attribute and linked to social status among boys. Among girls the association between physical activity ability and social status was more complex, appearing to differ by the norms of the group to which participants belonged. Some participants reported that low activity ability could be perceived as desirable in some social groups. Participants reported that friends provide support to initiate physical activity via co-participation (i.e. engaging in activity together); modeling of being active; and providing verbal support to engage in activity. Enjoyment was the most important factor in maintaining activity participation with participating in activity with friends a key factor influencing enjoyment. Friendship groups affect both the initiation and maintenance of youth physical activity. Children belong to several groups and engage in different activities with different groups. Simple strategies that aim to promote physical activity via the different friendship groups could be an effective means of promoting increased physical activity in young people.

Childhood obesity has become an emotive and serious problem in Europe. In the UK, it has generated a great deal of interest by the media, health professionals, food companies, scientists, and more recently, the government. Upward trends have been recorded in most countries, levels are interestingly variable, and the origins of this variation have not been explained. The role of physical activity and sedentary habits in childhood obesity is not clear. This is partly due to measurement problems. Accelerometry is offering some clearer insight into patterns and levels of activity that may be influential in the determination of children's long term energy balance. Examples of this research are presented.

Similar to adult obesity, childhood obesity has recently become a serious threat to public health. Children face the same environmental and lifestyle challenges that have made high energy dense food and drink increasingly available and opportunities for energy expenditure through transport and active play less likely. Governments are becoming concerned but research has been under funded, is relatively scarce in the UK and has provided little sound evidence on which to base interventions. Physical activity seems to be declining and there is some evidence that time spent in sedentary pursuits such as TV watching is increasing and that this may be related to obesity. However, not all children are inactive and it may be more fruitful to independently examine different elements of activity such as play, walking and cycling as transport, organised sports, and active jobs so that children’s profiles of activity can be mapped on an individual and group level. Recent research using accelerometry is providing insight into those elements which produce significant energy expenditure in a child’s daily routine. The school and the structure to the school day appear particularly important. It is also likely that attention will need to be paid to parenting - the anxieties that parents demonstrate when making decisions about the freedom of their child to be active. Furthermore, without neighbourhoods that are safe and attractive for activity it is unlikely that levels will be increased. For physical activity to contribute to reversing the trend in childhood obesity, a multi-factorial and multi-agency solution will be required that involves schools, the home, the neighbourhood and considered local planning and provision.