Middle School Students' Body Mass Index and Physical Activity Levels in Physical Education

One of the most critical public concerns in the United States is the rapid increase in childhood obesity, partly due to the social and environmental changes (e.g., excessive TV and computer use, pressures of standardized testing, etc.) in the past few decades, which has resulted in less physical activity in school children’s daily routines (Zhu, 2008). In particular, youth obesity has increased from 7% to 19% in children (ages 6–11 years) and from 5% to 17% in adolescents (ages 12–19 years) in the past three decades (Hedley et al., 2004; Ogden, Flegal, Carroll, & Johnson, 2002; Ogden et al., 2006). Childhood obesity often tracks into adulthood (Guo & Chumlea, 1999) and generally leads to numerous physical and mental health problems, such as type 2 diabetes, cardiovascular disease, and low self-confidence (U.S. Department of Health and Human Services [USDHHS], 2001). Regular physical activity participation has been identified as an indispensible strategy to prevent childhood obesity (Ogden et al., 2006). However, it is posited that children and adolescents’ physical activity levels tend to decline during the developmental years (Parish & Treasure, 2003). It has been well documented (Kulinna, Martin, Lai, Kliber, & Reed, 2003; Parish & Treasure, 2003) that this activity declines with age during adolescence, but carefully designed research can help educators develop effective strategies that can control and reverse this trend. Schools can play a critical role in preventing obesity in children and adolescents by increasing physical activity levels and health-related physical fitness regimens among this population (Pate et al., 2006; Wallhead & Buckworth, 2004). More than 95% of children and adolescents are enrolled in schools where they can participate in structured physical education programs (Levin, McKenzie, Hussey, Kelder, & Lytle, 2001; Simons-Morton, O’Hara, Parcel, Baranowski, & Wilson, 1990; USDHHS, 1996). Healthy People 2010 includes an objective to promote health and reduce chronic disease through school children’s daily physical activity levels (USDHHS, 2000). Specifically, it has been recommended that students’ active participation in physical education classes should comprise at least 50% of the class time (Pate et al., 2006). Physical education programs are a potentially important channel for promoting physical activity and fitness among youth and are an avenue for fighting childhood obesity (Simons-Morton et al., 1990). Therefore, increasing students’ activity levels in physical education classes has become imperative for physical educators and health promoters. Obesity is defined as an excess of body fat mass (Bellizzi & Dietz, 1990). Measuring students’ body mass index (BMI; kg/m2) in school is one approach to assess obesity (Nihiser et al., 2007). BMI and skinfold measurements have been used widely in field settings due to their convenience and low cost. Researchers have suggested that BMI has a strong correlation to skinfold thickness in children (e.g., Rowland, 1990). BMI testing has advantages over skinfold measurement in that it is not intrusive and it is easy to calculate with acceptable accuracy (Raustorp, Middle School Students’ Body Mass Index and Physical Activity Levels in Physical Education