- Title
- High Intensity Interval Training (HIIT) for adolescents’ physical, mental and cognitive health
- Creator
- Costigan, Sarah A.
- Relation
- University of Newcastle Research Higher Degree Thesis
- Resource Type
- thesis
- Date
- 2020
- Description
- Research Doctorate - Doctor of Philosophy (PhD)
- Description
- Background: Current physical activity and fitness levels among adolescents are low, increasing their risk of various chronic health conditions. Current guidelines recommend participation in 60 minutes or more of daily moderate-to-vigorous physical activity (MVPA), several hours of light physical activity per day and vigorous activity (including muscle and bone strengthening activities) on at least three days per week. In comparison to activity of light and moderate intensity, vigorous physical activity appears to have the strongest physical health benefits. However, less is known regarding physical activity of different intensities and adolescents’ cognitive and mental health. Schools are ideally placed for the delivery of interventions to increase adolescents’ participation in physical activity. However, previous school-based interventions have been largely ineffective due to focus on motivational determinants of behaviour and poor implementation. A range of barriers to the implementation of school-based physical activity interventions have been noted in the literature, including teachers’ workloads, competing instructional requirements and the availability and quality of resources (e.g., activity resources, personnel, facilities). There is an emerging consensus that school-based interventions designed to increase physical activity and fitness should be time-efficient and scalable, for easy implementation. Regular participation in High Intensity Interval Training (HIIT) can provide adolescents with a dose of vigorous physical activity that is beneficial for their physical health. To date, the majority of HIIT studies conducted with adolescents have examined the efficacy of sprint-based programs in clinical settings. Although the efficacy of HIIT for improving adults’ metabolic health is now well established, it is not known if this type of activity is effective or feasible when conducted with adolescents in schools. Further, some evidence suggests HIIT has a positive impact on mental health and cognition in adult population groups; however, the impact of HIIT for adolescents’ cognitive and mental health has not been addressed in the literature. Objectives: This thesis by publication presents a series of studies that were undertaken to address gaps in the literature. The primary aim of this thesis was to evaluate the effects of a school-based HIIT program on adolescents’ health-related fitness. Given current evidence for the importance of engaging in sufficient physical activity and attainment of high fitness levels for positive mental health and cognitive outcomes, this body of research also presents a number of studies addressing key secondary aims. In order to provide an adequate overview and context for the Primary aim, investigation of Secondary aims 1 and 2 precede the primary aim. The primary and secondary aims of this thesis are presented below: Secondary aim 1: To determine the associations between vigorous physical activity and well-being (i.e., positive and negative affect) in a large sample of adolescents. To address this aim, secondary analysis of data from the ‘Activity and Motivation in Physical Education (AMPED)’ study was conducted. To determine the association between physical activity intensity and affective well-being (positive and negative), Actigraph accelerometers were used to assess physical activity, and the short form Positive and Negative Affect Scale for Children was used to measure well-being. Quantile regression was used to analyse the data. Light and moderate physical activity was not associated with well-being. However, higher levels of vigorous physical activity were associated with more positive affect and less negative affect to a turning point of 36-37 min/day, after which the association between vigorous physical activity and well-being reversed. The negative association between vigorous physical activity and negative affect was more pronounced in females than in males. Secondary aim 2: To systematically review evidence regarding the efficacy of HIIT for improving health-related fitness in adolescent populations. To determine the effect of HIIT on health-related fitness components, in comparison to non-training control groups or moderate intensity comparison groups, a systematic review with meta-analyses was conducted. Subgroup moderator analyses were conducted to determine if HIIT effects differed according to duration of study, type of comparison group or risk of bias. The review included 20 studies examining cardiorespiratory fitness, body composition and muscular fitness. Included studies demonstrated moderate to high risk of bias. The effects of HIIT on cardiorespiratory fitness and body composition were large and medium, respectively. Study duration was a moderator for the effect of HIIT on body fat percentage. Intervention effects for waist circumference and muscular fitness were not statistically significant. Primary aim: To evaluate the effects of a school-based HIIT program on adolescents’ health-related fitness. The primary aim of this thesis was to investigate the effects of a school-based HIIT program on adolescents’ health-related fitness, mental health and cognition. To evaluate effects of school-based HIIT, a three-arm RCT was conducted in one secondary school in Newcastle, Australia. A total of 65 participants completed baseline testing and were randomised into one of three conditions: aerobic exercise program (AEP) (n = 21); resistance and aerobic exercise program (RAP) (n = 22); or control (n = 22). Participants in the AEP and RAP groups participated in three HIIT sessions per week for 8-weeks. Two HIIT sessions were delivered during scheduled PE lessons, and a third session delivered at lunchtime. Sessions duration progressively increased, ranging from eight to 10 minutes (weeks 1-3: 8 minutes; weeks 4-6: 9 minutes; weeks 7-8: 10 minutes), with a work to rest ratio of 30secs:30secs. The AEP and RAP sessions were delivered by the research team. Assessments were conducted at baseline and post-intervention to detect changes in cardiorespiratory fitness (multi-stage shuttle-run), muscular fitness (push-up, standing long jump tests), and body composition (BMI, BMI-z scores, waist circumference). Overall, the strongest intervention effects were observed for participants in the RAP group, which included a combination of resistance and aerobic exercises during sessions. Secondary aim 3: To determine the feasibility of a school-based HIIT RCT for adolescents and their teachers. To address this aim, program feasibility was evaluated based on consent rate, retention rate and program adherence. Acceptability was assessed using post-intervention evaluation questionnaires completed by students and teachers participating in the intervention. The intervention achieved high recruitment, good adherence and retention. Of the 43 intervention participants, 31 completed the post-program evaluation questionnaire and reported that the program was enjoyable, motivating and beneficial to their health. All the teachers (n = 4) involved in the HIIT intervention completed post-program evaluation questionnaires. Teachers agreed that: (i) their students enjoyed participating in the intervention; (ii) they could confidently deliver the HIIT sessions during their own lessons with minimal professional learning; and (iii) they intended to include HIIT in their PE lessons in the future. Secondary aim 4: To evaluate the impact of a school-based HIIT RCT on adolescents’ cognitive and mental health outcomes. To address this aim, the efficacy of two HIIT protocols [AEP and RAP] for improving mental health and cognitive function of adolescents was evaluated. Participants’ executive function (Trail Making Test), psychological well-being (Flourishing Scale), psychological distress (Kessler Psychological Distress Scale), and physical self-concept (Physical Self-Description Questionnaire) were assessed pre- and post-intervention. To detect changes in mental health and cognitive function outcomes, statistical analyses of the outcomes were conducted using linear mixed models, and Cohen’s d was used to measure effect size. Small improvements in executive function and psychological well-being were evident in the AEP group. Moderate improvements in executive function, and small improvements in well-being and perceived appearance, were observed for the RAP group. Secondary aim 5: To examine the impact of a school-based HIIT RCT on adolescents’ objectively measured physical activity. The HIIT intervention also aimed to address the impact of school-based HIIT on overall physical activity and to explore potential physical activity compensation. GENEActiv accelerometers were used to assess objective physical activity at baseline and week one of the intervention, to detect changes in moderate and vigorous physical activity. Embedding HIIT within the school day had a moderate effect on vigorous physical activity in comparison to controls. In addition, compensation analyses suggested that adolescents were more active on days when they participated in HIIT.
- Subject
- HIIT; adolescents; fitness; mental health; cognition; thesis by publication
- Identifier
- http://hdl.handle.net/1959.13/1428342
- Identifier
- uon:38620
- Rights
- Copyright 2020 Sarah A. Costigan
- Language
- eng
- Full Text
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