OBJECTIVES:Urban-rural comparisons between those who maintain traditional lifestyles such as pastoralist Maasai children, and those who live in cities such as Nairobi, provide implications on how urbanization is associated with children's physical activity (PA) and sedentary behavior (SB) patterns. This study compares PA and SB volumes and patterns across different segments of the week among children in Maasai village and Nairobi city in Kenya.METHOD:A total of 261 children (11.4 ± 1.3 years) from Maasai (n = 118) and Nairobi (n = 143) participated in this cross-sectional study. Moderate- to vigorous-intensity PA (MVPA) and SB on weekdays (before, during, and after school) and weekends (morning, afternoon, and evening) were calculated using accelerometers (ActiGraph). Screen time and sleep duration were assessed using questionnaires.RESULTS:Maasai children were more physically active than Nairobi children with MVPA (min/day) of 166.6 and 81.4 for Maasai and Nairobi boys and 116.4 and 77.4 for Maasai and Nairobi girls, respectively. Our week segments analyses suggested that Maasai children were more active both in and out of school than Nairobi children. Additionally, Nairobi children spent more time watching television and playing computer games than Maasai children. There was no significant difference in sleep duration between Maasai and Nairobi children.CONCLUSION:Our findings suggest that urbanization is negatively associated with activity patterns both in and out of school in Kenyan children. This is concerning given that Kenya is currently undergoing rapid urbanization, which may lead to further reductions in PA among Kenyan children.

Health benefits of physical activity are well known, yet available physical activity data is limited from children living in African and Asian countries. The purpose of the cross-sectional study was to evaluate and compare physical activity and sedentary behavior patterns, particularly hourly variations, among children in Kenya and Japan. Participants included 298 primary school students (122 Kenyan, 176 Japanese) aged 9–12 years. Physical activity and sedentary behavior were measured with accelerometers. Domain-specific physical activity, screen time, and proportion of children using active transport to school were measured by questionnaire. A two-way ANOVA (countries × time) was used to examine the differences in the activity patterns between Kenyan and Japanese children. The results from the present study demonstrated that Kenyan children spent more time in moderate-to-vigorous physical activity compared to Japanese children (p < 0.05) with the greatest differences found for weekday evenings (for boys and girls) and weekend afternoons (for girls). This suggests that these were ‘critical periods’ to differentiate the physical activity levels between Kenyan and Japanese children. However, a higher proportion of the children from Japan used active transport to school and spent less time in television viewing and computer gaming. The results suggest that both countries have successes and challenges that can aid in developing effective and country-specific intervention strategies for promoting physical activity.