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oai:figshare.com:article/32605365 2026-06-08T16:43:31Z portal_1132 item_type_8 month_year_06_2026

Assessing the Impact of Accelerometer Methodology upon the Physical Activity and Mental Health Relationship in Children and Adolescents Lin Wang (21059504) Accelerometer Methodology One in five adolescents worldwide is affected by mental health conditions, with depression and anxiety being particularly common. Evidence shows that physical activity (PA) is beneficially associated with these conditions in children and adolescents (Chapter 2), and accelerometer-based assessments are now widely adopted to better capture youth activity behaviours (Chapter 3). However, evidence examining the relationship between accelerometer-measured PA and mental health has often overlooked the impact of accelerometer methodological choices. Previous studies are limited in exploring how different accumulation patterns are associated with depression and anxiety, beyond PA volume (Chapter 2). This thesis aims to build upon recent evidence by advancing understanding of accelerometer-measured PA (Chapters 3-4) and how different PA accumulation patterns are related to mental health in children and adolescents. The thesis also explores moderators, including accelerometer methodological choices and demographic factors. The thesis comprises a systematic review and meta- analysis (Chapter 4) and two observational studies (Chapters 5-6) to investigate cross-sectional and longitudinal associations between accelerometer-measured PA and mental health. Findings from the systematic review and meta-analysis showed that although accelerometer-measured PA was associated with mental health (association range: partial r = -0.17 to -0.21; odds ratio (OR) = 0.95 to 0.98), epoch length and accelerometer wear location significantly influenced the magnitude of this relationship. In particular, associations were stronger when epoch length was shorter (below 15 seconds: r = -0.32 vs above 15 seconds: r = 0.08) and when the accelerometer was worn on the wrist (wrist r = -0.29 vs waist r = -0.10) (Chapter 4). PA accumulation patterns showed that higher weekend activity was associated with better mental health (range β = -0.37 to -0.49), whereas higher between-day variability was associated with poorer mental health in adolescents (β = 0.24 to 0.56) (Chapter 5). Furthermore, more frequent, shorter bout of moderate-to-vigorous physical activity (MVPA) was more strongly associated with better mental health than less 2 frequent, longer bout of MVPA (ranging from β = -0.21 to -0.33) (Chapter 6). Specifically, the association between weekend PA and better mental health was stronger among females (Chapter 5), and the association between more frequent, shorter bouts of MVPA and better mental health was also stronger in females (Chapter 6), whereas the relationship between higher between-day variability and poorer mental health was stronger in males (Chapter 5). In general, these associations tended to be stronger among pre- and early- pubertal adolescents (Chapters 5-6). Higher socioeconomic status appeared to provide a protective effect on mental health, particularly when PA patterns were irregular. This thesis provides novel and important evidence of the beneficial association between PA and mental health in children and adolescents. Maintaining stable and sufficient between-day PA, increasing weekend activity, and engaging in frequent shorter daily MVPA bouts may offer long-term protection. Adopting standardised accelerometer methodologies, considering individual differences in PA patterns, and developing innovative advanced PA metrics can enhance understanding of mental health (Chapter 7).<p></p> 2026-06-05T00:00:00Z Text Thesis 10779/exe.32605365.v1 https://figshare.com/articles/thesis/Assessing_the_Impact_of_Accelerometer_Methodology_upon_the_Physical_Activity_and_Mental_Health_Relationship_in_Children_and_Adolescents/32605365 All rights reserved Open Access after 2027-12-08