- Title
- Evaluation of a school-based intervention designed to improve health-related fitness in adolescent boys from schools in low-income communities: the ‘Active Teen Leaders Avoiding Screen-time’ (ATLAS) cluster randomised controlled trial
- Creator
- Smith, Jordan James Paul
- Relation
- University of Newcastle Research Higher Degree Thesis
- Resource Type
- thesis
- Date
- 2015
- Description
- Research Doctorate - Doctor of Philosophy (PhD)
- Description
- Background: Growing concerns over obesity, physical inactivity, and worsening levels of physical fitness among youth have led to a proliferation of school-based intervention studies in recent years. School-based programs aimed at increasing physical activity and fitness, and preventing obesity have demonstrated promise, but results have been inconsistent and short-term. While there is evidence to suggest that previous programs have been less effective for adolescents, there are also relatively few interventions that have been evaluated among this group. Furthermore, many previous interventions have been limited by poor methodological quality. Based on the limited success of previous programs, it has been suggested that future interventions should be directed at specific sub-groups of the population (e.g., males or females). Indeed, there are clear sex differences in regards to key health behaviours (e.g., physical activity, recreational screen-time, and sugar-sweetened beverage [SSB] consumption), suggesting that intervention approaches should be differentiated for boys and girls. It has also been recommended that interventions be evaluated among those most at risk of future ill-health. Youth living in low-income communities are disproportionately affected by poor health outcomes. Consequently, there is a strong rationale for targeted intervention approaches among this population. Finally, considering the recognised links between physical fitness and health outcomes, attempts to engage youth through innovative and theoretically driven physical activity and fitness programs are warranted. Objectives: This thesis-by-publication presents a series of studies, which aim to address a number of gaps within the current evidence base. The principal focus of this thesis is the development and evaluation of the ATLAS (Active Teen Leaders Avoiding Screen-time) cluster randomised controlled trial (RCT), a school-based program aimed at improving health-related fitness and key health behaviours among adolescent males attending schools in low-income communities. Given emerging evidence of the importance of muscular fitness and movement skill competence for achieving and maintaining good health, this thesis also presents a series of studies aimed at investigating key secondary aims related to these topics. Considering the chronology of the research included within this thesis, and the importance of these studies for providing context to the Primary aim, Secondary aims 1 and 2 are presented first. The Primary aim of this thesis and the remaining secondary aims are then presented, as listed in the order below. xxvi Secondary aim 1: To systematically review the evidence base regarding the health-benefits of muscular fitness for children and adolescents. A systematic literature search of six electronic databases was conducted. Cross-sectional, longitudinal and experimental studies that quantitatively examined the association between muscular fitness and health outcomes among youth populations were included. In total, 110 studies encompassing six health outcomes were included in the review. Meta-analyses were conducted to determine the pooled effect size if at least three studies reported standardised coefficients. Included studies generally demonstrated moderate to low risk of bias. Strong evidence was found for an inverse association between muscular fitness and total and central adiposity, and cardiovascular disease and metabolic risk factors. Strong evidence was also found for a positive association between muscular fitness and bone health and self-esteem. The evidence for an association between muscular fitness and musculoskeletal pain and cognitive ability was inconsistent or uncertain. Secondary aim 2: To develop and evaluate a test battery for assessing adolescents’ resistance training (RT) movement skill competency. The aim of this study was to describe the development and assess test-retest reliability and construct validity of the Resistance Training Skills Battery (RTSB) for adolescents. The RTSB provides an assessment of resistance training skill competency and includes six exercises (i.e., body-weight squat, push-up, lunge, suspended row, standing overhead press and front support with chest touches). A convenience sample of adolescents completed the RTSB on two occasions separated by seven days. Participants also completed the handgrip strength, timed push-up and standing long jump tests to assess the construct validity of the RTSB. The RTSB can reliably rank participants in regards to their resistance training competency and has the necessary sensitivity to detect small changes in resistance training skill proficiency. Finally, the RTSB was found to be an independent predictor of muscular fitness, providing preliminary evidence for construct validity. Primary aim: To evaluate the effects of the ATLAS cluster RCT on health-related fitness and RT movement skill competency among adolescent boys attending schools in low-income communities. The primary aim of this thesis investigated whether participants randomised to the ATLAS intervention group demonstrated more favourable changes in body composition, muscular fitness and RT movement skill competency, compared with a control group. The ATLAS intervention was evaluated using a cluster RCT in 14 secondary schools located in low-income communities of New South Wales, Australia. In total, 361 adolescent boys were assessed at baseline and were xxvii randomised at the school level to the intervention or control group. The boys were reassessed 8 months later, following the conclusion of the program. Analyses followed intention-to-treat principles. There were no significant intervention effects for body composition (i.e., body mass index [BMI], waist circumference, or percent body fat), or for maximal strength (i.e., hand grip dynamometry). However, compared to boys in the control condition, intervention boys demonstrated greater muscular endurance (i.e., push-up repetitions) and RT skill competency at 8-month follow-up. Secondary aim 3: To evaluate the effectiveness of the ATLAS intervention on adolescent boys’ physical activity, screen-time, and sugar-sweetened beverage consumption. The ATLAS intervention also aimed to address a number of key weight-related behaviours. At 8-month follow-up, adolescent boys randomised to the intervention condition reported less recreational screen-time and SSB consumption, compared with boys in the control group. No significant intervention effects were found for accelerometer-assessed total physical activity (i.e., counts per minute) or moderate-to-vigorous physical activity. Compliance with physical activity monitoring was poor. Secondary aim 4: To describe the development and implementation of a smartphone application designed to promote physical activity and reduce screen-time among adolescent boys. The ATLAS smartphone app was developed to complement the ATLAS intervention and replace paper-based resources. The app was used for physical activity monitoring, goal setting, and assessment of RT technique. Further, the app provided tailored motivational messages throughout the intervention period. Participants completed process evaluation questionnaires and focus groups, which included questions on the acceptability and usage of the ATLAS app. Seventy percent of boys in the intervention group reported having access to a smartphone or tablet device. Focus group findings suggested that boys’ engagement with the smartphone app was limited. Barriers to the implementation and evaluation of the app included limited access to smartphone devices, technical problems with the push notifications, lack of access to usage data and the challenges of maintaining participants’ interest in using the app. xxviii Secondary aim 5: To examine the potential mediating effects of RT movement skill competency on health-related fitness and physical activity. RT movement skill development was a key component of the ATLAS intervention. Three separate multi-level mediation models were analysed to investigate the potential mediating effects of RT skill competency on boys’ body composition, muscular fitness and physical activity using a product-of-coefficients test. Analyses followed the intention-to-treat principle. Improvements in RT skill competency significantly mediated the effect of the intervention on percent body fat and muscular fitness. No significant mediated effects were found for physical activity.
- Subject
- obesity prevention; adolescents; intervention; fitness; physical activity; school; thesis by publication
- Identifier
- http://hdl.handle.net/1959.13/1309904
- Identifier
- uon:21958
- Rights
- Copyright 2015 Jordan James Paul Smith
- Language
- eng
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