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Trial registered on ANZCTR

Registration number
Ethics application status
Date submitted
Date registered
Date last updated
Date data sharing statement initially provided
Date results information initially provided
Type of registration
Prospectively registered

Titles & IDs
Public title
High intensity interval training and mental health in adolescents
Scientific title
High intensity interval training and mental health in adolescents
Secondary ID [1] 294047 0
Universal Trial Number (UTN)
Trial acronym
Linked study record

Health condition
Health condition(s) or problem(s) studied:
Mental health 306591 0
Condition category
Condition code
Public Health 305687 305687 0 0
Other public health
Mental Health 305879 305879 0 0
Other mental health disorders

Study type
Description of intervention(s) / exposure
This cluster-randomised controlled trial will be conducted within eight intermediate level schools in Auckland. Total number of participants is therefore expected to be 400 school students subject to recruitment rate. Two classes will be recruited from each school; one will be randomly allocated to HIIT, and the other to a control group who will continue with usual practice Physical Education class delivery. Assessments will be conducted at baseline and post intervention period (~18 weeks), and at follow-up 11 weeks.. The primary outcome measure will be mental health assessed by the Strengths and Difficulties Questionnaire. Secondary outcome measures include mental wellbeing, aerobic fitness, muscular fitness, and cognitive function. Additionally, participants’ attitudes to, and perceptions of exercise will be assessed, and the teachers’ perceptions of their competence and willingness to continue delivery of HIIT will be determined. Teachers will receive resources and a professional development session (with approximately 4 ongoing brief feedback sessions throughout the
term) to deliver the intervention, which will consist of brief HIIT sessions to fit within two PE periods per week. The sessions will be designed to be deliverable in a variety of settings such that specialist space is not required, and with minimal, portable equipment. Matauranga Maori will underpin the design of a component of sessions. Specific aspects related to Level 4 Health and Physical Education Curriculum in New Zealand will be incorporated into succinct discussions after sessions. Analysis will account for moderators (i.e.., decile, initial fitness level, score on the strengths and difficulties questionnaire, classification of weight status) and relative efficacy. The single pre-intervention one-day teacher professional development session and ongoing brief feedback throughout the intervention will contribute towards the 12 practising teacher criteria requirements for maintenance of teacher registration within NZ. They will address the latest evidence on the benefits of HIIT across all outcomes in order to enhance teacher buy-in and understanding. Teachers will learn to deliver the HIIT using the SAAFE principles developed by Lubans and colleagues, within an Aotearoa New Zealand context. A written HIIT resource will then be provided to teachers, along with brief videos of exercises to be used. They will also receive a 'class-pack' of heart rate monitors. Teachers will be encouraged to complete an action plan and identify barriers and solutions to facilitate the integration of HIIT into their PE lessons.
The professional development session will be delivered by the research team (all full-time academic staff members, PhD’s) to the teachers of the intervention class. The HIIT sessions will be delivered by the teachers to the participant students in class.
The HIIT sessions delivered by the teachers will be structured to fit within 10-15 minutes, twice per week, and involve a variety of work to rest ratios based on existing HIIT protocols. Participants will wear heart rate monitors and have their de-identified heart rate displayed on screen for them to target at least 85% of predicted heart rate maximum as a guideline intensity towards the end of each work phase. The sessions will be deliverable in a variety of settings such that specialist space is not required, and with minimal, portable equipment. Promotion of adherence and enjoyment by utlising pair and small group peer interaction but avoiding larger group competitive ‘drills’ in order to avoid competitiveness and disenfranchisement by lower fit participants will be incorporated. Our matauranga Maori approach to HIIT sessions will be designed around cultural narratives and histories, such as the discovery of Aotearoa by Kupe, or the ascension of Tane through the 12 heavens to provide cultural context. These narratives will be woven throughout the delivery of exercise sessions to improve cultural relevance and provide innovative opportunities to utilise Maori knowledge in a contemporary education setting. The format of sessions will require a setting specific approach, and some variation in delivery is inevitable given different teacher delivery. Brief reflective questions at the end of each HIIT session will prompt critical thinking around the participant’s own relationship with vigorous physical activity and how that evolves over the course of the intervention period. The questions will be developed in conjunction with the teachers. Specific NZ Health and Physical Education Level 4 Curriculum learning area strands, achievement objectives, and key competencies addressed will include:
Movement concepts and motor skills strand, and achievement objectives:
• Movement skills through the process of acquisition of exercise competency
• Positive attitudes though the aspects of resilience and perseverance.
Personal Health and Physical Development strand, and achievement objectives:
• Managing self and sense of responsibility for incorporating regular and enjoyable physical activity into personal lifestyle to enhance wellbeing.

Over two school terms (~18 weeks), ~30-35 sessions in total will be delivered in class by the
All HIIT sessions will be delivered in school (Year 8 level) during usual Physical Education class times. The professional development session will be delivered to the teachers involved with the intervention class at the University facility of the research team.
Will be assessed via recording of class attendance. No strategy will be employed to enhance
adherence as it is reliant on usual attendance to class.

Intervention code [1] 300321 0
Treatment: Other
Comparator / control treatment
Usual Physical Education (PE) Curriculum delivery at Year 8.
Given that each different school has a unique approach to meeting curriculum requirements, the usual PE programme control groups will inevitably be somewhat varied, but the intention is to compare relative efficacy of HIIT with the current programme as it is. Normal PE at this level involves twice weekly class sessions of 1-2 hours in length, covering introductory sports skills, some game based activities, and at times, a component of ' fitness' subject to individual teacher determination.
Control group

Primary outcome [1] 304782 0
Mental Health - Strengths and Difficulties Questionnaire
Timepoint [1] 304782 0
Baseline, post-intervention (primary timepoint), and follow-up
Secondary outcome [1] 343159 0
Psychological well-being: The Warwick-Edinburgh Mental Wellbeing Scale is a 7-item questionnaire. Participants respond on a 5-point scale that best describes the frequency with which they experience thoughts such as "I’ve been feeling optimistic about the future" over the last 2 weeks.
Timepoint [1] 343159 0
Baseline, post-intervention (primary timepoint), and follow-up
Secondary outcome [2] 343160 0
Aerobic fitness - PACER (BEEP) test 20m shuttle
Timepoint [2] 343160 0
Baseline, post-intervention (primary timepoint), and follow-up
Secondary outcome [3] 343161 0
Muscular fitness with a 90° push-up to failure, a modified pull-up (supine pull), a body mass squat, and grip strength. The movement quality of push-up, pull-up, and squat exercises will be assessed during the testing with the Resistance Training Skills Battery rating scale. Lubans, DR, Smith, JJ, Harries, SK, Barnett, LM, and Faigenbaum, AD. Development, test-retest reliability, and construct validity of the Resistance Training Skills Battery. J Strength Cond Res 28(5): 1373–1380, 2014
Timepoint [3] 343161 0
Baseline, post-intervention (primary timepoint), and follow-up
Secondary outcome [4] 343162 0
Body mass (kg), electronic scale
Timepoint [4] 343162 0
Baseline, post-intervention (primary timepoint), and follow-up
Secondary outcome [5] 343163 0
Waist circumference (cm), non-elastic tape measure
Timepoint [5] 343163 0
Baseline, post-intervention (primary timepoint), and follow-up
Secondary outcome [6] 343164 0
Autonomous motivation for exercise using the Behavioural Regulations in Exercise Questionnaire – Version 2 (BREQ-2) (Markland & Tobin, 2004). The BREQ-2 includes sub-scales for intrinsic and identified regulations, and the mean of these sub-scales is calculated to create an autonomous motivation variable.
Timepoint [6] 343164 0
Baseline, post-intervention (primary timepoint), and follow-up
Secondary outcome [7] 343165 0
Executive function: The Trail Making Test (TMT) is a measure of visual attention, speed, scanning, speed of processing and mental flexibility and has been validated in youth. The TMT involves a two part visual task in which participants are required to draw a line from one point to the next as quickly as possible. Lower scores indicate greater cognitive performance,
Timepoint [7] 343165 0
Baseline, post-intervention (primary timepoint), and follow-up
Secondary outcome [8] 343166 0
Student voice: Small group interviews will be conducted with student participants post intervention period. These group discussions will be semi-structured with a casual approach to engage this cohort. Recorded transcripts will then be coded and thematically analysed
Timepoint [8] 343166 0
Baseline, post-intervention (primary timepoint), and follow-up
Secondary outcome [9] 343623 0
The International Fitness Scale (IFIS) for youth to determine self-perceived physical fitness using a 5 question, 5 point scale response survey. This will be used in conjunction with a newly developed six item HIIT self efficacy measure. Sanchez-Lopez M, Martinez-Vizcaino V, Garcia-Hermoso A, Jimenez-Pavon D, Ortega FB. Construct validity and test-retest reliability of the International Fitness Scale (IFIS) in Spanish children aged 9-12 years. Scandinavian Journal of Medicine and Science in Sports
Timepoint [9] 343623 0
Baseline, post intervention (primary timepoint), and follow-up
Secondary outcome [10] 343624 0
Using well-established procedures Paired Axivity™ AX3 accelerometer/inclinometer units will be used to objectively assess activity patterns for the duration of one school week. The daily and total counts will be registered with the average time spent in vigorous physical activity. The AX3 device will be fastened to the thigh and lower back using waterproof medical dressing and worn at all times.
Timepoint [10] 343624 0
Baseline, post intervention (primary timepoint), and follow-up
Secondary outcome [11] 343625 0
Teacher perceptions of competence and willingness to continue the HIIT sessions in future via interview, and general perceptions on their student's experience with participating in the HIIT sessions.
Timepoint [11] 343625 0
Post intervention (primary timepoint).

Key inclusion criteria
All students in Year 8 able to participate in normal Physical Eduction class activity
Minimum age
12 Years
Maximum age
14 Years
Both males and females
Can healthy volunteers participate?
Key exclusion criteria
Unable to participate in normal Physical Education class activity

Study design
Purpose of the study
Allocation to intervention
Randomised controlled trial
Procedure for enrolling a subject and allocating the treatment (allocation concealment procedures)
Sealed opaque envelopes
Methods used to generate the sequence in which subjects will be randomised (sequence generation)
Simple randomisation
Masking / blinding
Blinded (masking used)
Who is / are masked / blinded?

The people assessing the outcomes
Intervention assignment
Other design features
Not Applicable
Type of endpoint(s)
Statistical methods / analysis
If there are the anticipated limited (~ <5%) number of missing observations or outcome variables, analysis based on actual data is generally sufficient. Opportunities to impute values will be considered, based on how actual data emerge. In particular, analysis of differential versus non-differential occurrence of missing observations and withdrawals will be carried out to assure that missing data are not systematic and further to account for potential bias in intention to treat analyses. For non-correlated values, conditional mean imputation will be considered. All imputations will be carried out consistent with the approaches laid out in Gelman and Hill. We will perform a sensitivity analysis to examine the effect of different strategies and intention to treat on the conclusions, with explicit reporting of missing observations and withdrawals. Generalised linear mixed effects models will be used to assess appropriately adjusted effects of the intervention on outcome measures at both time points. Subgroups considered for analysis will consist in gender, school decile, SDQ score, and baseline fitness.. This trial being pragmatic in intent and design, all efficacy analyses will be based on a strictly interpreted intention to treat analysis set, with per protocol analyses being treated as sensitivity analyses. Analysis will account for moderators (i.e., decile, mental health score). Adjusted regression models will undergo sensitivity analysis and leave-one-out analyses. Leave-one-out analysis is a re-sampling strategy and has the benefit of identifying observations that may have an undue influence on the overall statistic.

Recruitment status
Date of first participant enrolment
Date of last participant enrolment
Date of last data collection
Sample size
Accrual to date
Recruitment outside Australia
Country [1] 9583 0
New Zealand
State/province [1] 9583 0

Funding & Sponsors
Funding source category [1] 298672 0
Other Collaborative groups
Name [1] 298672 0
National Science Challenge / Curekids
Address [1] 298672 0
Laundry Building
PO Box 90 907
Victoria Street West
Auckland 1142
Country [1] 298672 0
New Zealand
Primary sponsor type
Auckland University of Technology
17 Antares Place
Mairangi Bay 0632
New Zealand
Secondary sponsor category [1] 297843 0
Name [1] 297843 0
Address [1] 297843 0
Country [1] 297843 0

Ethics approval
Ethics application status
Ethics committee name [1] 299626 0
Ethics committee address [1] 299626 0
Ethics committee country [1] 299626 0
New Zealand
Date submitted for ethics approval [1] 299626 0
Approval date [1] 299626 0
Ethics approval number [1] 299626 0

Brief summary
The mental health of our youth is imperative. Emerging evidence indicates that the particular potency of vigorous physical activity on mental health, and a spectrum of other health and wellbeing outcomes for adolescents, are probably inter-related to psychological wellbeing. High-intensity interval training (HIIT) is a specific form of vigorous activity involving a small number of repeated brief, intense bouts of exercise, typically lasting from 20 to 120 seconds each, interspersed with a recovery phase of varying durations. HIIT represents an effective, expedient and possibly palatable option for adolescents, of particular importance given the precipitous trend of deterioration in their health and wellbeing. Adolescents residing in areas of high socioeconomic inequality are particularly vulnerable. Adolescence is a key stage in the development of health behaviours and influential on adult health behaviour habits, hence the imperative to determine approaches that influence lifelong personal health and wellbeing is compelling. Partnering with schools and teachers to integrate HIIT into the curriculum represents a potentially scalable and sustainable way to facilitate adolescents with the understanding that a personal exercise habit for holistic wellbeing need not be based on high duration commitment. In our Aotearoa New Zealand context, with an underpinning of a matauranga Maori enhanced approach, we may have an option that provides a unique combination of potency, palatability, practicality, and translatability to reach our youth in a school environment. Our aim is to contribute to a reduction in mental health problems of adolescents through determining the effects of embedding a matauranga Maori enhanced, teacher-delivered HIIT programme within the school health and physical education (PE) curriculum in socioeconomically deprived neighbourhoods. We also seek to determine the potential for it’s broader implementation via determination of the overall acceptability of such an approach to participant students, their schools, and the teachers involved in it’s delivery.
Trial website
Trial related presentations / publications
Public notes

Principal investigator
Name 81082 0
Dr Nigel Harris
Address 81082 0
AUT Millennium
17 Antares Place
Mairangi Bay 0632
Country 81082 0
New Zealand
Phone 81082 0
Fax 81082 0
Email 81082 0
Contact person for public queries
Name 81083 0
Dr Nigel Harris
Address 81083 0
AUT Millennium
17 Antares Place
Mairangi Bay 0632
Country 81083 0
New Zealand
Phone 81083 0
Fax 81083 0
Email 81083 0
Contact person for scientific queries
Name 81084 0
Dr Nigel Harris
Address 81084 0
AUT Millennium
17 Antares Place
Mairangi Bay 0632
Country 81084 0
New Zealand
Phone 81084 0
Fax 81084 0
Email 81084 0

Data sharing statement
Will individual participant data (IPD) for this trial be available (including data dictionaries)?
No/undecided IPD sharing reason/comment
Further analyses still to be conducted prior to dissemination
What supporting documents are/will be available?
No other documents available
Summary results
Have study results been published in a peer-reviewed journal?
Other publications
Have study results been made publicly available in another format?
Results – basic reporting
Results – plain English summary