Types of young people active in sport
The types of young people who are active, and why and how they get involved in physical activity, are determined by a complex mix of genetic, social and personal factors. At the personal level, physical and psychological attributes shape the individual’s motivation to expend energy in play. The social and physical environments interact with these intrinsic factors through facilitatory and inhibitory influences embedded within the home, neighbourhood and school. Genetic factors account for about 25–30 per cent of the variability in sports participation. Presented with a child about whom we knew nothing, and asked to predict that child’s activity patterns, we could make a very good estimate using just two pieces of information — gender and age.
Gender
By far the best predictor of the amount and type of physical activity a child enjoys is based on their gender. There is overwhelming evidence that boys are more active than girls at any age. Boys’ daily physical activity levels are about 5–10 per cent greater than girls’. On average, boys spend about 68 minutes per day playing sport, compared to 36 minutes for girls. This equates to 19 per cent of boys’ total daily energy expenditure, but only 12 per cent of girls’ daily energy expenditure. Boys’ play styles and preferred sports are also different. Boys occupy more space and are more sensitive to restrictions in space. Sports dominated by boys include Australian football (seven boys for each girl), cricket (three to one) and soccer (2.5 to 1). Sports dominated by girls include netball (11 to 1) and dance (four to one). Finally, boys have different motivations for sports participation; they tend to value extrinsic motivations (rewards and prizes) more than girls.
Age
After gender, the next best predictor is age. Overall levels of physical activity decline with age, with sharp falls around puberty. This is a common pattern to a wide range of species, and may be related to changes in levels of the neurotransmitter dopamine and dopamine receptors. Puberty may represent an evolutionary ‘tipping point’ at which the benefits of play are outweighed by the risks. Declines in adolescence tend to be largely in non-organised physical activity rather than in organised sports, particularly among girls. When children are divided into activity clusters, girl ‘screenies’ (high levels of television and video games, low sport) tend to be older than other clusters. The amount of time spent playing sport decreases at a rate of 7 per cent per year of age in girls, and 3 per cent in boys, while the percentage of daily energy expenditure devoted to sport is fairly constant. There are declines in participation with age in most sports, particularly in aerobics, swimming and dance (declines of 30–50 per cent per year), and cricket, soccer and basketball (15–23 per cent per year). Participation in Australian football and tennis is constant across the 10–14-year-age band, while table tennis becomes increasingly popular. Finally, older children prefer less adult and family involvement in their play, prefer to mix with larger groups of friends, and are less influenced by high-profile athletes, coaches and other adults.
Socio-economic status
Socio-economic status is a weak and inconsistent indicator of participation in physical activity. It is not associated with the number of minutes Australian children devote to sport or play in their daily schedule, nor does socio-economic status differ among children from different activity clusters. However, socio-economic status gradients do exist in children’s attitudes towards physical activity, with children from lower socio-economic status groups being less likely to prefer active play with friends. The number of sports a child plays declines with socio-economic status, supporting claims that cost may exclude some families from certain types of organised sport.
Family structure
Aspects of family structure (single versus two parents; siblings versus no siblings) can overlap with socio-economic status. We divided families into four structural types: 1O for single-parent families with only one child (no siblings); 1S for single-parent families with more than one child; 2O for two-parent families with only one child; and 2S for two-parent families with more than one child. In both daily minutes of sports participation and overall physical activity level, boys from 2S families fared significantly better than boys from 1O families. Children from 1O families also had higher screen time. Children from 1O or 1S families reported playing less often with their families, were more likely to prefer quiet to active play, and were less likely to consider active play to be fun. Some of these effects are probably due to the synergistic effect of siblings, and the reduction in average family size is of concern for future activity patterns.
Parents as models
Parents may affect the physical activity participation of children both directly (by serving as role models), and indirectly (by providing logistical support for sports, etc.). About one child in three cited parents as the main influence on their activity choices. The effect of direct modelling, however, appears to be small. Children, particularly older children, rank the influence of parents as motivators uniformly low. Children who reported that their fathers were involved in sport reported playing more sports themselves and twice as many weekly sessions of play. There were no associations between reports of mother’s involvement and self-reported sports participation.
The play environment
Both the amount of play space available and its layout affect activity levels of children. In most industrial countries there has been a trend away from open, unstructured areas to suburbanised, closed, divided and structured cityscapes. The amount of physical activity equipment in the home and the school affects play behaviours, as does the available play space. This is particularly true for boys, whose games tend to be more wide ranging. Smaller backyards reduce the amount of free play. The structure of neighbourhoods is also important: the presence of major arterial roads, poor lighting, cul-de-sac street layouts and the agglomeration of neighbourhood shops into shopping centres all discourage active transport.
Figure 3 A conceptual diagram of the Youth Physical Activity Promotion Model highlighting the different variables that lead to physical activity
Source: Adapted from Welk, Corbin and Dale 2000
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