Physical Activity in Girl Scout Junior Troop Meetings – Introduction

Sedentary behavior, including seated television viewing, computer use, and video games (collectively screen time) may be contributing to overweight and obesity (collectively overweight) in comparison to non-sedentary activities (Epstein et al., 2001). Child and adolescent television viewing has been found to be associated with overweight, poor cardio-pulmonary fitness, raised serum cholesterol, and smoking in early adulthood; all are established risk factors for cardiovascular morbidity and mortality later in life (Hancox et al., 2004). Strong and colleagues (2005) suggest reducing sedentary screen time to less than two hours per day in order to increase physical activity and health and also recommend that school-aged children participate in 60 minutes or more of moderate-to-vigorous physical activity (MVPA) that is enjoyable and developmentally appropriate. A study by Epstein and colleagues (2001) showed that targeting either a decrease in sedentary behaviors or an increase in physical activity was associated with significant decreases in percent overweight and body fat. However, if children are not provided with access to enjoyable physical activity, they may substitute other sedentary behaviors when targeted sedentary behaviors are reduced (Epstein et al., 2001).
Childhood overweight is a major concern, considering it is an important predictor of adult obesity (Magarey et al., 2003; Whitaker et al., 1997) and the subsequent increased risk of morbidity and mortality in adulthood (Flegal et al., 2005; Gunnell et al., 1998; Must & Strauss, 1999). There has been little progress to report for the child and adolescent overweight prevalence objectives of Healthy People 2010. For years 2003 to 2006, 16.3% of children and adolescents were at or above 95th percentile of BMI according to the age- and sex-specific references given in the 2000 CDC growth charts (Ogden et al., 2008), three times the target prevalence (5%) for the Healthy People 2010 objectives. For the same period, 31.9% of children and adolescents had a BMI for age at or above the 85th percentile (Ogden et al., 2008).
Physical activity levels tend to decline across childhood and adolescence, especially among girls (Kimm et al., 2002; Trost et al., 2002). A study by Kimm and colleagues (2002) examined longitudinal physical activity changes in a large cohort of adolescent girls (from age 9 or 10 to age 18 or 19) and found a substantial decline in physical activity. By age 18 or 19 years, the majority of girls were found to engage in virtually no habitual physical activities, other than those performed during school. Also, high body mass index (a marker of overweight) was associated with a greater decline in activity among girls (Kimm et al., 2002). In another study, the overall prevalence of meeting recommended levels of physical activity were found to be higher among males (43.7%) than females (25.6%) (Eaton et al., 2008).