Degree Name

Doctor of Philosophy


School of Health and Society


Background The transition from primary to secondary school is one of the life transition periods during which significant behavioural changes may occur. However, there is little evidence on concurrent changes in sleep, sedentary behaviour and physical activity (PA) (collectively known as 24-hour movement behaviours) over a 24-hour period during this school transition period. Further, the combined associations between time spent in 24-hour movement behaviours and psychosocial health are still under-researched in children. This information may inform the development of future movement behaviour intervention strategies and guidelines to assist children in making a healthy transition to secondary school. The overall aim of this doctoral thesis was to explore changes in 24-hour movement behaviours and their associations with children’s psychosocial health over the transition from primary to secondary school.

Methods This thesis is comprised of four research papers, one of which is a systematic literature review and the other three are original research studies using data from two longitudinal surveys. The first and third studies analysed primary data from a longitudinal school-based survey that followed a cohort of children in New South Wales, Australia from their final year of primary school (Year-6; aged 10-12y) to their first year of secondary school (Year-7; aged 11-13y). The second study used national data from Waves 4 (2010) and 5 (2012) of the Longitudinal Study of Australia Children (Kindergarten cohort) when participants were in primary (aged 10-11y) and secondary school (aged 12-13y), respectively.

Results The systematic literature review identified five articles that reported only changes in PA, while one reported changes in both PA and sedentary behaviour during the school transition period. There were no studies that examined changes in sleep duration or changes in all three movement behaviours concurrently.

The first study (n=83) investigated changes in the accelerometer-measured 24-hour movement behaviour composition and adherence to the Australian 24-Hour Movement Guidelines during the school transition period. An unfavourable change was observed in the movement behaviour composition, with increased time spent sedentary and decreased time in sleep and PA. The change in the weekday movement behaviour composition was significantly more prominent compared to that of the weekend. Furthermore, there was a substantial decrease in the proportion of children meeting the integrated 24-hour movement guidelines (i.e., from 20.5% to 3.6%).

The second study (n=909) investigated changes in the domain-specific movement behaviour composition as measured by a single-day time-use diary (67.4% school day; 32.6% non-school day), and explored whether these changes were associated with changes in children’s psychosocial health during this transition period. A more drastic change in movement behaviour composition was observed among the school day sample compared to the non-school day sample. Furthermore, the change in movement behaviour composition was significantly related to changes in prosocial behaviour among boys. Specifically, increased time spent in social activities and recreational screen use (relative to other activity domains) were associated with decreased prosocial behaviour. There were no significant associations between the change in movement behaviour composition and the changes in psychosocial health among girls.

The third study examined the cross-sectional (n=127) and longitudinal associations (n=88) between 24-hour movement behaviour composition, recreational screen use and children’s psychosocial health. The movement behaviour composition and recreational screen use levels were independently associated with psychosocial health outcomes cross-sectionally but not longitudinally. Relative to other behaviours, more time spent in sleep and less time spent in light-intensity PA were associated with lower levels of internalising problems and total psychosocial difficulties. Conversely, higher sedentary time was associated with greater internalising problems. High levels of recreational screen use (>2 h/day) were associated with greater externalising problems, total psychosocial difficulties and psychological distress.

Conclusion This thesis has provided new evidence to advance the understanding of children’s 24-hour movement behaviours and their combined associations with psychosocial health during the transition from primary to secondary school. It is recommended that an integrated intervention approach addressing the full composition of 24-hour movement behaviours be adopted to effectively improve children’s movement behaviour profiles during this transition period. Future research should also continue to measure and analyse both intensity- and domain-specific movement behaviour compositions given the differing associations noted with children’s psychosocial health.

FoR codes (2008)




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.