Outcome
Type |
Measure |
Description |
Time frame |
Safety issue |
Other |
Confounding variables |
Age of peak height velocity will be used to assess the somatic maturation of participants. Participants' physical activity and sleep at all time-points will be assessed by a Chinese version of the International Physical Activity Questionnaire, short form and a validated Chinese version of the Pittsburgh Sleep Quality Index, respectively. |
Maturity, subjectively measured physical activity and sleep will be measured at baseline, immediately after the intervention and two month following the cessation of the intervention. |
|
Other |
Interview |
Semi-structured interviews will be conducted with participants and physical education teachers, separately, when the intervention completed. Pre-determined open questions will be asked during the interview, including feedback on enjoyment/usefulness of the intervention, continue performing/using the HIIT exercises and perceived barriers and facilitators for doing/delivering the HIIT exercises. |
immediately after the intervention |
|
Primary |
Cardiorespiratory fitness |
Cardiorespiratory fitness will be measured using 20-metre shuttle run. The 20-meter shuttle run requires participants to run back and forth between two lines positioned 20 meters apart. To complete a shuttle, participants must reach the other end before a designated beep sounds. The beep is set to allow the participants to start at 8.5 km/h and increase the speed by 0.5 km/h as indicated by a triple beep. The test concludes if a participant fails to complete two consecutive shuttles or volitionally discontinues. |
Changes from baseline to immediately after the intervention and two month following the cessation of the intervention. |
|
Secondary |
Muscular strength |
Upper and lower body strength will be assessed using hand grip and standing long jump, respectively. A digital dynamometer with an adjustable grip, with participants standing and elbow in 90-degree flexion, will be employed for measuring the upper body strength in kilogrammes. The test will be performed twice on both hands and an averaged number of the four measurements will be used for reporting. Standing long jump will be measured with an electrical tester, which has high sensitivity and greatly improved accuracy. Participants stand behind the start line with their feet apart and are allowed to swing their arms quickly to jump as far as possible. Each participant will have three attempts, with the best one recorded. |
Changes from baseline to immediately after the intervention and two month following the cessation of the intervention. |
|
Secondary |
Wellbeing |
The Chinese version of Strengths and Difficulties Questionnaire (SDQ) will be used to assess the behavioural and emotional outcomes of participants. |
Changes from baseline to immediately after the intervention and two month following the cessation of the intervention. |
|
Secondary |
Enjoyment |
Enjoyment of physical activity will be measured using physical activity enjoyment scale. |
Changes from baseline to immediately after the intervention and two month following the cessation of the intervention. |
|
Secondary |
Motivation |
Motivation to autonomously engage in physical activity will be assessed using a modified Behaviour Regulation in Exercise Questionnaire. |
Changes from baseline to immediately after the intervention and two month following the cessation of the intervention. |
|
Secondary |
Affect |
Affect will be assessed via a Chinese version of the International Positive and Negative Affect Schedule Short Form |
Changes from baseline to immediately after the intervention and two month following the cessation of the intervention. |
|
Secondary |
Academic performance |
Academic performance will be evaluated by utilising the school's end-of-term academic examinations. The total score for the academic examinations of each participant during term one (January 2023) and term two (July 2024) will be obtained from the school to be used as pre-intervention and immediately post-intervention data for academic performance, respectively. |
Baseline and immediately after the intervention |
|
Secondary |
Height |
Height will be measured in centimetres with a portable stadiometer. |
Changes from baseline to immediately after the intervention and two month following the cessation of the intervention. |
|
Secondary |
Weight |
Weight in kilograms will be determined with a Tanita device (Tanita Corp., Tokyo, Japan). |
Changes from baseline to immediately after the intervention and two month following the cessation of the intervention. |
|
Secondary |
BMI |
Weight and height will be combined to report BMI in kg/m^2 |
Changes from baseline to immediately after the intervention and two month following the cessation of the intervention. |
|
Secondary |
Waist circumference |
Waist circumference in centimetres will be measured using a tape. |
Changes from baseline to immediately after the intervention and two month following the cessation of the intervention. |
|
Secondary |
Body fat percentage |
Body fat percentage will be determined with a Tanita device (Tanita Corp., Tokyo, Japan). |
Changes from baseline to immediately after the intervention and two month following the cessation of the intervention. |
|
Secondary |
Physical activity |
Physical activity for a subset of participants (n = 60) will be objectively assessed using GENEActiv wrist-worn accelerometers (Model GAT04, Activinsights Ltd, Cambridgeshire, England) over a span of four weeks, comprising one week before and after the intervention as well as the initial and concluding weeks of the intervention. |
Baseline, first week and last week of the intervention and first week following the completion of the intervention. |
|
Secondary |
Bone health |
A heel ultrasound test will be performed via a Achilles heel ultrasound machine (GE Medical Systems Lunar, USA). Participants will be seated with one foot on the foot plate, and alcohol will be applied to ensure proper membrane contact. A transducer on one side of the heel will convert an electrical signal into a sound wave, which will pass through the heel to the other side and be received and analysed by another transducer. |
Changes from baseline to immediately after the intervention and two month following the cessation of the intervention. |
|
Secondary |
Perceived physical ability |
A 6-item validated Perceived Physical Ability Scale will be utilised to evaluate the PA-related self-efficacy. The items are structured in response scales having a 1- to 4-point format. High scores would indicate a high self-perception of physical ability, whereas low scores would reflect a low self-perception. |
Changes from baseline to immediately after the intervention and two month following the cessation of the intervention. |
|
Secondary |
Flanker task |
Participants' inhibition will be assessed using a modified Flanker task. In the task, participants respond as quickly and accurately as possible to the direction of the fish in the middle which is flanked by another four fishes that are either swimming towards the same direction (congruent) or opposite direction (incongruent) to the central target fish. Participants will be instructed to press the "F" button on the keyboard if the fish swims towards left or "J" if towards right. The task consists of 104 trials in total, with a 1-minute rest when participants finished the first 52 trials. The result will be reported and compared as reaction time and accuracy. |
Changes from baseline to immediately after the intervention and two month following the cessation of the intervention. |
|
Secondary |
Visual 2-back task |
Working memory will be assessed using a modified visual 2-back task. Stimuli are sequences of animals (i.e., pig, giraffe, panda, snail and duck) which will be presented on the screen one-by-one. Participants will be instructed to respond to the stimulus as quickly and accurately as possible by either press the "F" button on the keyboard if the stimulus is identical to the one that appeared two trials back or "J" if not. The task consists of 52 trials in total, with a 1-minute rest when participants finished the first 26 trials. The result will be reported and compared as reaction time and accuracy. |
Changes from baseline to immediately after the intervention and two month following the cessation of the intervention. |
|
Secondary |
Colour-shape switch task |
Cognitive flexibility will be evaluated by a modified version of colour-shape switch task. In the task, participants will be instructed to react as quickly and accurately as possible to press the "F" button or "J" on the keyboard, with the following cues: If the object is at the top of the screen: press "F" if it is blue, press "J" if it is green; If the object is at the bottom of the screen: press "F" if it is square, press "J" if it is triangular. The task consists of 128 trials in total, with a 1-minute rest when participants finished the first 64 trials. The result will be reported and compared as reaction time and accuracy. |
Changes from baseline to immediately after the intervention and two month following the cessation of the intervention. |
|