Degree Name

Doctor of Philosophy


School of Education


Sedentary behaviour (SB) is considered a risk factor for non-communicable diseases and long periods of sedentary time (ST) have been associated with an increased risk of mortality in adult populations. Although investigation in young children (aged 1 to 5.9) is less consistent, this period has been identified as a critical period in which sedentary habits may be established and track throughout life. The aim of this Doctoral thesis was to investigate the prevalence, correlates and measurements of SB in toddlers (aged 1 to 2.9 years) and pre-schoolers (aged 3 to 5.9 years). This thesis is divided into several chapters. Chapter I states the significance, aims and research questions of the thesis. Chapter II is a review of the evidence on SB that is presented based on the Behavioural Epidemiology Framework aiming at i) establishing the links between SB and health; ii) describing the methods for measuring SB; iii) identifying the factors that influence SB; (iv) evaluating interventions to change SB; and (v) translating research into practice. Chapter III includes specific descriptors of the studied samples, as well as the material and methods used for assessment. Chapters IV and V present systematic reviews of the prevalence and correlates of objectively measured SB during the early years. Chapter VI is a methodological study, aimed at assessing the concurrent validity of the hip-mounted ActiGraph GT3X+ with the thigh-mounted activPAL accelerometer for measuring SB in toddlers. The subsequent chapters comprise studies aimed at examining the levels and bouts of objectively measured SB in Australian toddlers and pre-schoolers by different day types (e.g., childcare days, non-childcare weekdays and weekends), cross-sectionally (Chapter VII) and longitudinally (Chapter VIII). Finally, Chapter IX presents a general discussion of the main findings of various studies of this thesis.

This thesis is unavailable until Wednesday, December 08, 2021



Unless otherwise indicated, the views expressed in this thesis are those of the author and do not necessarily represent the views of the University of Wollongong.