Further research needs
While there has been a tremendous amount of research over the last decade or so on fitness, fatness and physical activity in children, there remain gaps in the literature and issues to be addressed, particularly in relation to effective interventions.
Peer group influence
Very little is known about the effect of the peer group on the amount and nature of physical activity in children. Recent studies in the psychological literature regarding personality and behavioural development in young people (for example, Harris 1999) have under-emphasised the impact of the family and stressed the importance of the friendship group. Consider the case of language, where children from families of non-English speaking backgrounds learn to speak accent-free idiomatic English with ease in spite of the parents’ poor English skills. Harris’s partitioning of variability between genetic and environmental influences suggests that the home exerts only a very small influence on behaviour. Work remains to be done on whether the same applies to physical activity behaviour.
Physical activity and academic performance
Recent meta-analyses have suggested that acute and chronic exposure to physical activity can significantly improve cognitive performance (Shephard 1997). Some intervention studies have been carried out in France, Canada and Australia where academic school time has been replaced by physical activity. While the results of these interventions were promising, each study had serious methodological flaws. This is a critical question, because physical education is being squeezed out of a crowded curriculum, and fear of decrements in academic performance is driving some parents to discourage their children from ‘too much’ involvement in physical activity.
Independent effects of screen time
There is some evidence that sedentary behaviour (that is, screen time) is an independent risk factor for paediatric fatness. This is an important question because high levels of physical activity may not compensate for high levels of screen time. There is a natural experimental group of interest — the so-called ‘techno-actives’ who combine high screen time and high sports participation.
Trickle down
There is a powerful and appealing argument in political circles that increasing resources for elite-level sport will eventually ‘trickle down’ to grassroots levels. This concept has led to interventions such as sponsoring sports stars to visit schools in the hope of boosting sports club membership, usually with poor results. One study (Hogan and Norton 2000) has found no evidence for this hypothesis. Another (Olds et al. 1994, forthcoming) found only weak relationships between children’s fitness and Olympic success across 37 countries. In the Multimedia Activity Recall for Children and Adolescents psychosocial questionnaire, fewer than 5 per cent of students listed visits by high-profile athletes and coaches as major influences on their physical activity decisions. This is in spite of the fact that children will often list sports stars as their heroes. We need to know more about the trickle-down effect to design rational and cost-effective interventions.
Winding the clock forward
Many studies have compared a relatively rosy picture of youth in the 1960s (lean, active and fit) to the situation in the 1990s (overweight, sedentary and unfit), and have produced a raft of suggestions designed essentially to ‘turn the clock back’ (get children walking to school again, increase membership of traditional sporting clubs, return to old-style physical education classes, redesign traditional neighbourhoods, reduce screen time). These suggestions fly in the face of large-scale socio-economic and demographic trends (economic rationalism that is reshaping retail neighbourhoods, increasing suburbanisation which increases dependence on automobiles, technological energy-saving devices which reduce the energy cost of work, consumption and daily life). What has not been done is to brainstorm solutions for the world as it will be. Such solutions might include harnessing children’s fascination with electronic technologies, fitting in with modern rhythms of work by expanding out-of-school-hours care that also exploit the critical window of activity, creating new forms of physical activity using mobile phones and the internet. In other words, we need lateral, futuristic solutions that adapt to the new social realities.
National uniform monitoring systems
At the moment, there are no good data series on secular changes in physical activity, and no general agreement on desirable levels of physical activity. Systems should be set up allowing national uniform monitoring systems. These should include measures of overweight, that is, body mass index, physical activity (including sports participation), and energy intake. Such systems could be administered by specially trained teachers on a national basis. They could be delivered, and data collected, through the internet. Automatic analysis and feedback could be linked to curriculum modules. International agreement on simple instruments would facilitate comparisons with other countries. A significant weakness in most existing instruments is in psychosocial questionnaires regarding issues such as barriers and motivations. When children say they like physical activity because it is ‘fun’, or do not exercise because they have ‘no time’, the amount of information conveyed is virtually zero.
The watershed of puberty
Pre-pubertal children have a natural drive to exercise, while post-pubertal children need to be coerced. There is a sudden drop-off in physical activity at puberty in both boys and girls. Puberty may be an evolutionary ‘tipping point’. Pre-pubertal children prefer unstructured play in small family and friendship groups; post-pubertal children prefer organised games with a wider circle of acquaintances. Research is needed on the social and physiological determinants of this change. An evolutionary psychology model may prove fruitful, as may neuropsychological approaches.
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