The influence of genetic and environmental factors on musculoskeletal motion and physical activity

Abstract

Human motion is complex and enables people to interact with the environment and conduct their daily activities. However, the physical activity levels of people living in modern society has reduced compared to ancestral environments, where people needed to undertake high rates of physical activity in order to pursue their prey and escape predators. In contemporary society, people living in rural areas undertake less vigorous activity due to mechanisation and industrialisation. In addition, sedentary behaviour has increased due to urbanisation, despite the fact that the health benefits of promoting general human movement through physical activity have been well established. The amount of physical activity of people living in urbanised areas also differs from those in rural areas. However, data related to physical activity are specifically lacking in developing countries. The aim of this thesis was to investigate genetic (heritability) and environmental contributions to musculoskeletal motion and physical activity in Mongolian adults. Chapter Two showed that too few studies have investigated the heritability of musculoskeletal motion. Chapter Three and Four found strong environmental contributions to light intensity physical activity, sedentary behaviour, and lumbar motion control, whilst high heritability was noted for higher intensities of physical activity and lumbar posture. Chapter Five identified that health benefits were the top motivator for physical activity, regardless of residential region, but barriers were region specific. Chapter Six found deceased physical activity along with prolonged sitting was negatively associated with lumbar motion, suggesting that increasing physical activity may promote lumbar motion. Incorporating health benefits as the top motivator into a physical activity intervention, as well as addressing region-specific barriers, may be beneficial in promoting individuals to be active in Mongolia.