High intensity interval training and mental health in adolescents

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. WHO 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. INTERVENTION MODE 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. NUMBER OF TIMES FOR INTERVENTION DELIVERY Over two school terms (~18 weeks), ~30-35 sessions in total will be delivered in class by the teachers. LOCATION 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. ADHERENCE 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.