Purpose:
The investigators aim to undertake an experimental trial using exercise training in adolescents, evaluating a theoretical model where mHealth technology, allowing biometric informed feedback and coaching, is incorporated into a structured home-based exercise and physical activity (PA) intervention. The overall objective is to have an evidence-based exercise and PA intervention ready to evaluate in a future randomised controlled trial (RCT).
Hypothesis:
It is hypothesized that this approach will increase both habitual PA and adherence to structured exercise of the appropriate intensity to promote improvements in cardiorespiratory fitness and vascular function.
Justification:
Current physical activity guidelines suggest adolescents should accumulate at least 60 minutes of moderate to vigorous physical activity (MVPA) per day. Yet globally, more than 80% of adolescents fail to achieve the recommended level of daily MVPA, and less than 25% of Canadian adolescents are sufficiently physically active. Adolescence is a time when sedentary habits predominantly manifest. Sedentary time increases by approximately 100 minutes/day between the ages 12 and 16 years, and there is a disproportionate number of inactive adolescent girls (82%) compared to boys (71%). Clearly current strategies to encourage appropriate levels of physical activity in adolescence are inadequate.
It is important to note that the current MVPA guidelines lack the intensity associated with the enhancement of cardiorespiratory fitness in youth (\~85-90% of heart rate maximum).Further, the extant data show that habitual physical activity is not related, or at best weakly related to direct laboratory measures of cardiorespiratory fitness in youth.
If we aspire to improve cardiorespiratory or vascular health in our younger population, we need to find ways to engage adolescents in sufficient exercise i.e., 40-60 minutes, 3 to 4 times per week at \~85-90% of heart rate maximum.
Objectives:
Primary Objective
1\) Determine the number of sedentary adolescents that are eligible to participate, the proportion of these who would be willing to take part in this trial, and their characteristics, and the number of participants retained at 6-months.
Secondary Objectives
1. Adherence to the exercise training.
2. Estimate precision of potential outcome measures required for sample size estimations for the definitive RCT.
3. Intervention acceptability
Research Design:
The study is a randomised controlled intervention, whereby participants will complete pre-randomisation baseline testing (T1) before a 3-month supported PA and exercise intervention is completed. Immediately post-intervention (T2) and 6-months after the intervention is completed
Statistical Analysis:
The proportion of eligible patients who consent to participate in the pilot will be presented, along with the proportions in each intervention group completing each follow up assessment and the reasons for withdrawal. Descriptive characteristics and outcome data will be summarized overall and by intervention group, as mean (standard deviation) for normally distributed continuous variables, median (interquartile range) for non-normally distributed continuous variables, and number (percentage) for categorical variables.
Interview data will be analysed using thematic analysis, which will allow the research team to discuss emerging themes and help the research team to explore the barriers and facilitators to the intervention and refine the theoretical model, assessing which elements of the intervention. are most effective for participants. As this is a pilot study there will be no formal comparisons between groups in the intervention.
