Abstract
Declines in physical activity levels have coincided with increasing rates of obesity in children. This is problematic because physical activity has been shown to attenuate weight gain in children. Active commuting to school is one way of increasing children’s physical activity. However, given the high rates of child pedestrian injury, preventive strategies to reduce these risks are needed. Programs such as the Walking School Bus provide opportunities to not only promote pedestrian safety but increase children’s energy expenditure.
‘Active commuting has been shown to increase overall physical activity in multiple countries . . .’
Children are engaging in considerably less physical activity now than they were 20 years ago. 1 For example, from 1991 to 1997, participation in physical education classes decreased from 42% to 28%, and the amount of time spent in actual activity during these times also declined. 2 It appears that this decrease has leveled off, 3 but no significant improvements have been reported. In the United States, only 8% of elementary schools and 6% of junior high and senior high schools provided daily physical education, and only 50% of elementary, 25% of junior high, and 5% of high schools required physical education in 2000. 4
This decrease in physical activity is not only seen for physical education classes. Children are also spending more of their leisure time engaged in activities that are sedentary. 5 Child use of computers during free time has increased drastically. Adolescent boys spend more than 15 hours a week using a computer and 22½ hours watching television. 5 In contrast, these children spend approximately 6.7 hours a week in moderate to vigorous physical activity. Once late adolescence is reached, only 5.1 hours a week are spent in moderate to vigorous physical activity. Although community recreation centers have been shown to promote physical activity in children, the children who have the lowest rates of physical activity are not very likely to use them. 6
Impact of Physical Activity on Health
Physical activity in children has multiple health benefits. For example, physical activity during adolescence reduces the risk of health problems such as cardiometabolic and vascular diseases. 7 It is also related to improved bone density, 8 improved body composition, and maintenance of weight loss. 9 Greater amounts of physical activity may also protect against weight gain. 10 Currently, it is recommended that children engage in 60 minutes of physical activity daily, 11 although the intensity of physical activity may be of greater importance than the overall amount. For example, as little as 15 minutes a day of vigorous physical activity has been shown to attenuate unhealthy weight gain in children. 12
Physical activity is one of the primary prevention and intervention strategies for improving health. 13 Regular physical activity reduces the risk of coronary heart disease, stroke, diabetes, hypertension, some cancers, and depression.14-18 Although the need for programs that promote physical activity is clear, there are multiple barriers that reduce the likelihood of children being active. One of these barriers is the physical environment. Specifically, urbanization has led to environments that are less conducive to engaging in physical activity. The neighborhoods in which many children live have heavy traffic or are otherwise unsafe for children to bicycle or walk. With this in mind, the World Health Organization has encouraged programs to be developed that allow children to actively and safely commute to and from schools. 19
Active Commuting to School
Commuting to school using nonmotorized transportation is known as active school transport (AST) and can include walking, running, cycling, skateboarding, rollerblading, and so on. 20 AST is associated with increased levels of physical activity and healthier body composition in children.21-23 Active commuting has been shown to increase overall physical activity in multiple countries, including Australia, 24 Canada,23,25 Columbia, 21 England, 26 Germany, 27 Norway and the Netherlands, 22 Scotland, 28 and the United States. 29 AST has several behavioral benefits as well. For example, AST increases physical activity through small changes in lifestyle habits, making use of naturally occurring means in the environment. A small lifestyle change is an effective method of increasing energy expenditure. 30 Additionally, people are more likely to continue to adhere over time to naturally occurring changes rather than engaging in exercise regimes. 31
Although the benefits of AST are clear, rates of AST have declined dramatically in the past 40 years, with only 16% of students walking or biking to school in 2001 32 compared with 48% in 1969. 33 In an attempt to promote AST, the walking school bus (WSB) program was developed. The WSB is a group of children who walk to and from school with volunteers who serve as escorts for each trip. The group identifies a “bus stop” or meeting place for the participants and proceeds as a group to actively commute. The WSB has been shown to increase active commuting time and minutes of moderate to vigorous physical activity. 29 Additionally, frequent walkers obtain as much as 25% more physical activity, gain 58% less body fat, and slow weight gain velocity by 50% compared to passive commuters. 34
Engaging in AST also increases the potential for an escalation in pedestrian injuries. However, a program like the WSB may also improve children’s pedestrian safety behaviors as adults are walking with children, providing an opportunity for modeling and learning to take place. The results on pedestrian safety behaviors for the WSB are somewhat mixed. 35 Children in the WSB are more likely to cross the street at a corner or crosswalk but are less likely to stop at the curb when crossing the street. 35 Although it is possible that children are less likely to stop at a curb because an adult is attempting to hurry children across the street, the reason for this decrease in safety behaviors has not been fully explored. Although the WSB does not take direct steps to teach children or train them in pedestrian safety, it provides children with an opportunity to practice these safety behaviors.
The Role of Pedestrian Injury Prevention
Streets are particularly hazardous for youth, especially when the design of most urban communities is taken into consideration. Urban designs have a tendency to promote the needs of the adult commuter over the needs of other street users. 36 Although some attempts have been made to study and improve urban design, 37 the majority of neighborhoods and communities still suffer from heavy traffic. As children are encouraged to be more active, the use of community space (including roads) will likely be needed for this activity to take place. There is a paucity of studies examining the relationship between increased physical activity in children and risk for pedestrian injury. Because it is unlikely for the design of current communities to be drastically changed in the near future, it is necessary for steps to be taken to improve child safety behaviors. As Schwebel and colleagues 38 have discussed, there are multiple steps that can be taken to further promote safety and protect children from pedestrian injury.
Conclusion
Pedestrian injury prevention should be an integral component of physical activity promotion programs and need not be limited to active commuting interventions. Children and families are often encouraged to increase physical activity in their neighborhoods, which may involve playing near streets and in areas where pedestrian injury may occur. The types of games and activities that children engage in during active play in community settings increase the likelihood of “darting out” behavior, which is a common cause of pedestrian injury. 38 Furthermore, because physical activity levels (including active commuting) are decreasing, children may have fewer opportunities to learn and practice pedestrian safety behaviors. 39 This lack of competence in pedestrian safety puts children at risk for injury. As a result, when working with children and families to increase physical activity in communities, attention should also be paid to incorporate pedestrian injury prevention strategies. 38