19.12.2014 - Ausgabe: 6/2014

The role of physical activity in the prevention of disorders and the improvement of health

By Anne Noack and Prof. Dr. med. Dr. Sportwiss. Christine Graf (German Sport University Cologne)

Exercise, play and sport are essential for the healthy overall development of children (see summary in Graf et al., 2014, Lees & Hopkins, 2013). These not only help with the acquirement of motor skills and abilities but also have specific effects on health (blood pressure, lipid levels, bone structure etc.), emotional, psychosocial and cognitive aspects.

Over the past 20 years, however, a steady decline in the amount of physical activity of children has been observed (cf. Bappert & Bös, 2007; Rethorst, 2004). According to the results of the German Health Survey of Children and Adolescents (KiGSS), only 24.2% of boys and 17.9% of girls of primary school age indulge in physical exercise for at least 60 minutes a day as recommended by the WHO (Bös et al. 2009). Currently, only one in three children aged 3 - 10 years plays outdoors on a daily basis, whereby percentages decrease with increasing age. While 81.9% of 3 - 4 year-old children play daily outdoors, the equivalent figure for 7 - 10 year-olds is just 70% (Krug et al., 2012). In contrast, the amount of time spent on sedentary activities, particularly the duration of screen time, is increasing considerably.

The results of the German Children and Media Study (KIM) of 2012 show that TV plays a major role in the daily lives of children and that they regularly watch TV. It seems that 79% of 6 - 13 year-old children watch TV almost every day and only one in two of these children plays indoors or outdoors daily. In addition, 50% of the study children regularly use a computer or access the internet. The KIM study also confirmed that the duration of screen time was increasing while that of outdoor physical activity was decreasing (Medienpädagogischer Forschungsverbund Südwest, 2013).

At present, it is difficult to predict the possible long-term consequences of these trends among children. But a reduction in motor performance capacity can already be detected and this is associated with an increased calorie intake, meaning that there is an enhanced risk of children being overweight or even obese.

Reduction of physical performance capacity
Data on the trends with regard to physical performance capacity are contradictory. This is partly because of the wide range of different evaluation methods employed, such as motor skills tests designed to assess coordination, reaction time, strength and stamina and tests used to measure exercise tolerance, such as spiroergometry. Some 130,000 children and adolescents aged 6 - 19 years from 11 different countries were assessed in the shuttle run test in the years 1981 - 2000. The results showed a mean annual reduction in aerobic fitness of approximately 0.5%, in other words, of 10% over the whole period (Tomkinson & Olds, 2007); at the same time, however, there was no accompanying decrease in anaerobic fitness with regard to the secular trend (Tomkinson, 2007). In Germany (Würzburg), 1,255 kindergarten children from a Cologne-based group were investigated (DeToia et al., 2009). In various tests designed to assess their coordination, strength and reaction time, the results for 44 - 47% of the children were below average. Detected in some 550 children of primary school age was a roughly 33% decrease in overall physical coordination (measured using a physical coordination test for children) and an approximately 25% reduction in stamina (6-minute run test; Graf et al., 2004). As part of the KiGGS survey, the motor abilities of 4,529 children were assessed in an accompanying motor skills module; their ability to stand on one leg, to balance while walking backwards, jump from side to side, to do a standing long jump, to do press-ups and their flexibility when bending forward were documented. Across all age groups, some 33% of the children and adolescents were unable to walk backwards for two or more steps while balancing on a 3 cm beam (Woll et al., 2011). When bending forward, 43% were unable to reach the level of the soles of their feet. A comparison of the results for the standing long jump with those for 1976 indicated that strength had declined by 14%. It is not currently possible to forecast with any degree of accuracy what the long-term effects of these developments on health might be. Yet it is already apparent that children who are physically fitter, in common with adults who are physically fitter, have a better health profile and exhibit fewer of the risk factors that predispose to cardiovascular disease (see summary in Graf et al., 2014).

Overweight children
According to the results of the KiGGS survey, some 9.0% of 7 - 10 year-old children living in Germany are overweight while 6.4% are obese (Kurth & Schaffrath-Rosario, 2007). Another similar survey is currently in progress. Internationally and in certain of the German states, there has been no increase in these percentages (Olds et al., 2011; Wabitsch, Moss & Kromeyer-Hauschild, 2014), but this is not the case among the so-called risk groups. In addition to family and thus genetic predisposition, there are also sociodemographic factors, such as an immigrant background and/or a poor level of education, that represent significant risks with regard to the development of obesity (cf. e.g. Graf et al., 2014). Lifestyle seems to play a very important role here in terms of the relative amounts of time spent in physical activity and in the sedentary consumption of audiovisual media. There is a significant correlation between the duration of screen time (particularly time spent watching TV) and an increase in BMI. It is often specified that the critical threshold when it comes to watching TV is in the range 3 - 4 hours daily (Tremblay et al., 2011).

The promotion of exercise and health
The developments outlined above mean that preventative and health-promoting measures have become essential. These need to be designed to encourage children to take more physical exercise and to reduce the time spent in sedentary activities. The current recommendations as they apply to individuals and to institutions, such as schools, are summarised in box 3 below; the health promotion and preventative measures need to be introduced at many different levels. We here differentiate between strategies that can be used by individuals to improve their behaviour and those designed to influence behaviour within certain situational contexts. Measures designed to improve behaviour in the individual have the objective of influencing concrete/individual factors that protect or represent a risk to health and also attempt to modify personal lifestyles. Context-related preventative strategies take into account the personal, professional and structural environment and are also thus to some extent dependent on economic and political factors. There are crossovers between these two sectors and these crossovers are themselves influenced by factors originating from very different fields. Sociocultural models, for example, try to explain the activity behaviour of children in terms of the interaction between these various fields (Davision et al., 2001; Hinkley et al., 2012). Hence, there is a correlation between a child's characteristics, such as age and gender, and its family, school and the associated conditions as defined by the local authority and policy-makers.

If preventative measures are to prove effective over the long term, the strategies employed to promote exercise and health must be appropriate to the corresponding environment.

A special case − outdoor exercise
Increasingly at the focus of research are the links between exercise and nature; it would appear that direct contact with the natural world has positive effects on physical, social and cognitive abilities and psychological well-being (Keniger et al., 2013).

It is also postulated that the willingness to undertake physical exercise is increased when this can be performed outdoors (Calogiuri & Chroni, 2014). This is also associated with
• an improvement of psychological status and of psychosocial factors (such as social skills)
• enhanced fitness and motor skills (e.g. coordination)
• increased creativity and improvement of academic performance factors, such as concentration and alertness
(modified from McCurdy et al., 2010)

Other factors that play a role are place of residence and the ease of access to locations where outdoor activities can be undertaken, such as a playground. Even the level of attraction represented by a playground can influence the extent to which children are willing to exercise outdoors. In a study undertaken in New Zealand, it was observed that the duration of activity of children correlated with the nature of the equipment available in a playground (Taylor et al., 2011). Another study reports that children, and in particular girls, tend to be more active in well-equipped areas than in bare open spaces (Farley et al., 2008). This means that particular attention must be paid to the design of playgrounds. The provision of an attractive range of exercise options is essential in order to motivate children to play outdoors. As they acquire pleasure in exercise, this should seduce them into adopting a more healthy lifestyle and thus prevent them becoming overweight.
Other locations in which children are active on a daily basis are the outdoor areas of kindergartens and schools. The level of physical activity of children is increased on school playgrounds that offer a larger number of permanent play options (Taylor et al., 2011). There is also a correlation between physical activity and well-maintained sports apparatus, such as football goals, basketball hoops and tennis courts (Sallis et al., 2001). It would thus seem that one way to encourage children to take more physical exercise would be to make school playgrounds and the outdoor areas of kindergartens as attractive for their users as possible.

Conclusions
In summary, the benefits of physical exercise and its associated positive effects on development have been clearly demonstrated; despite this, there is a trend towards a preference for sedentary activities, particularly those involving the consumption of audiovisual media, with the relevant consequences. Parents and child carers need to be aware of the correlations between exercise and health and thus must be willing to act as role models in this context. However, the issue is (also) essentially a problem that permeates society as a whole and has its roots in educational and economic factors. To what extent, for example, do local authorities dedicate sufficient space to areas designed for outdoor exercise? In order to be able to reverse current trends, it is thus not only essential to instruct parents and carers in the roles that they should be playing, but also to create the required political (including urban planning) and economic framework that will both encourage and make it possible for children to take more exercise. The targets of this strategy are not only institutions such as kindergartens and schools, but also outdoor areas and open spaces, such as playgrounds and outdoor fitness trails for young people (and adults).

 

References

Contact author for reference list
For more information, please contact C.Graf@dshs-koeln.de
 

photo: eibe