The Negative Effects of Obesity

CHAPTER I

INTRODUCTION

1.1 Background

The prevalence of obesity in the United States and worldwide is an increasing major health concern. In the United States, more than two thirds of the adult population is overweight or obese, while worldwide obesity rates have more than doubled in the past three decades (Dewan et al., 2013; del Porto et al., 2012). The definition of being overweight, as defined by the World Health Organization, is having a body mass index ≥ 25 kg/m2, while obesity is defined as having a body mass index ≥ 30 kg/m2 (WHO 2008). Body mass index is defined as body weight divided by body height squared. The increase in obesity is especially troubling due to the fact that obesity has been associated with various health problems including diabetes, stroke, heart disease, some types of cancers, and a generally lower quality of life (del Porto et al., 2012; Wearing et al., 2006). Musculoskeletal impairments of function and mobility have also been linked to obesity, including osteoarthritis, osteoporosis, back pain, gout, and other disorders of the lower limbs and feet (Anandacoomarasamy et al., 2008; Wearing et al., 2006). These impairments can lead to difficulties in basic activities of daily living (del Porto et al., 2012; Wearing et al., 2006). The risk of functional decline has been shown to increase with increasing body mass (del Porto et al., 2012; Himes et al., 2012). These physical limitations lead to decreased balance ability, altered gait patterns, and reduced muscle strength, which are three of the top risk factors for falls, especially in older adults (del Porto et al., 2012; Zecevic et al., 2006). With the rise in prevalence of obesity and this group’s known functional limitations, overweight and obese ind...

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...r descent have been shown to be more demanding tasks than bipedal stance or walking respectively, few studies have assessed the effects of balance performance and locomotion in the obese during these tasks (Hills et al., 2002; Wearing et al., 2006). The purpose of this study was to examine the biomechanics of the torso, pelvis, and lower limbs during single leg standing and stair descent in normal and high body mass index individuals. The primary research question was to discover whether there were differences in kinematic, kinetic, and temporospatial parameters between these groups during these tasks. Based on the previous limited research on the obese performing these and other related activities, it was hypothesized that the overweight group would exhibit diminished static and dynamic postural stability during single leg standing and stair descent, respectively.