Objectives: The aim of this project will be to evaluate the efficacy of a lifestyle PA counselling program for physically inactive first responders with at least mild symptoms of either anxiety, depression or stress and their chosen support partners compared to a waiting list, and to determine the mediating effect of autonomous motivation. Additionally, the randomised controlled trial will be complemented with qualitative interviews to provide a deeper context and understanding to the quantitative findings. To the best of our knowledge, no randomized controlled trial to date has examined the outcomes of an online physical activity counselling intervention using peer-support in firefighters.

Methods: Within mixed methods randomized controlled trials, we will follow a sequential explanatory design. In this design, qualitative results complement and help interpret quantitative findings. In order to address the main aims, a randomized controlled trial will be executed. CONSORT statement will be followed for reporting findings. Protocol will be submitted to clinicaltrials.gov. For addressing the secondary aim of the study, the study will follow a qualitative design based on interpretative phenomenology. Phenomenology is a model used for describing, understanding, and interpreting the lived experiences of the participants by means of discourse analysis. For the quantitative component, two arms with 24 firefighters will be required. Additionally, chosen support partners will enter the intervention arm. Participants in the intervention arm will be invited to a private facebook page where the researcher will upload weekly educational posts regarding different aspects of physical activity. For the qualitative component, participants will be invited to 2-3 focus groups where the experiences of the participants on the program will be discussed.

Background:

Posttraumatic stress disorder (PTSD) is characterized by a combination of emotional, behavioural, and physiological symptoms following exposure to a traumatic event. Due to a greater exposure to traumatic events, first responders such as firefighters tend to have worse general well-being, higher risk of problematic alcohol use, and worse sleep quality, which consequently results in mental health problems, and also increases the risk of firefighters of developing PTSD compared to the general population. Evidence-based guidelines for the treatment of PTSD consider psychotherapy and pharmacotherapy as first line treatment. However, less than 10% of first responders with PTSD seek these guideline-informed treatments. One of the reasons is that first responders have a unique culture of self-reliance and strength, where mental health issues are considered a weakness. A culture of not showing weakness, together with fear of stigma and of confidentiality breach are the main barriers for seeking traditional mental health treatment.

Physical activity (PA) and its structured form, exercise, are a non-stigmatizing, easily accessible and promising add-on prevention and treatment interventions for a wide range of mental disorders including depression, anxiety- and stress-related disorders. It has an effect size similar to commonly used pharmacotherapy in patients with anxiety disorders. Furthermore, PA-based interventions have shown to be effective in improving sleep quality and reducing alcohol consumption. Adding on the mental health benefits, PA-based interventions can also target the cardiometabolic co-morbidity commonly observed in people with depression, anxiety- and stress-related disorders and in first responders. Therefore, PA might be a promising treatment modality for physically inactive first responders with depression, anxiety, or stress symptoms. Current guidelines strongly recommend 150-300 minutes of moderate PA or 75-150 minutes of vigorous PA, or an equivalent combination of moderate-to-vigorous PA.

In order to successfully implement PA-based interventions as prevention and treatment programs, research should explore effective ways to deliver the intervention in a way that is appealing for the target population. E-health and new technologies could provide a novel and less stigmatising approach to mental health interventions. It is an accessible and low-cost tool that could be effective for delivering PA interventions, increasing PA levels and improving mental health outcomes in people with psychiatric disorders or mental distress. Social media, more specifically Facebook, is a promising platform that has been previously used for supporting PA interventions for people with severe mental illness. The use of a private Facebook group to deliver these interventions could increase the feeling of belongingness and facilitate peer-to-peer support.

Social support is an essential aspect of adherence to PA interventions. Furthermore, social and family support are well-known protective factors against mental distress after prolonged exposure to trauma. Recent research suggests that partners, family members, or friends (commonly known as "informal caregivers") of first responders with mental distress have poorer mental health compared with the general population. Moreover, informal caregivers are also more likely to be sedentary, defined as wake-time spent sitting, reclined, or lying down quietly, than the general population. Including informal caregivers as support partners in a PA intervention could be beneficial not only for the first responders, but for the health of their informal caregivers. Another relevant factor which has been found to impact implementation of PA in daily living is the quality of the motivation to engage in PA. Previous research has found evidence that higher levels of autonomous motivation are related to more leisure time spent in physical activity in firefighters. However, despite the calls for more research examining the mediating effect of autonomous motivation on PA-based interventions, there is still a lack of causal evidence on the influence of autonomous motivation on PA-related behaviour change in physically inactive firefighters.

Therefore, the aim of this project will be to evaluate the efficacy of a lifestyle PA counselling program for physically inactive first responders with at least mild symptoms of either anxiety, depression or stress and their chosen support partners compared to a waiting list, and to determine the mediating effect of autonomous motivation. Additionally, the randomised controlled trial will be complemented with qualitative interviews to provide a deeper context and understanding to the quantitative findings. To the best of our knowledge, no randomized controlled trial to date has examined the outcomes of an online physical activity counselling intervention using peer-support in firefighters.

Aims:

Main aims:

• To evaluate the efficacy of a lifestyle PA counselling program in physically inactive firefighters with depression, anxiety and stress symptoms and their support partner compared to waiting list.

Secondary aims:

• To evaluate the mediating effect of autonomous motivation and perceived social support on the improvements on PA levels and mental health outcomes after a lifestyle PA counselling program.
• To understand the experiences of firefighters and their support partners participating in a lifestyle PA counselling program.

General hypotheses

Based upon of the aforementioned aims, the following hypotheses will be tested:

• PA levels, mental health outcomes, quality of life, and sleep quality of firefighters and their support partners will improve after participating in a PA counselling intervention.
• Autonomous motivation and perceived social support will partially mediate the improvements on PA levels and mental health outcomes of firefighters after participating in a PA counselling intervention.

It is important to indicate that qualitative research does not require a hypothesis, but a research question to drive the study. The research question for the secondary aim of the study is "How is the experience of participating in a PA counselling intervention to increase levels of PA and improve mental health outcomes, quality of life and sleep quality?".

Design:

Mixed-methods designs facilitate the assessment of the perspectives and experiences of the participants while providing numerical data, and can offer deeper and wider understanding of a research question than qualitative or quantitative methodologies alone. For this reason, the use of mixed-methods designs in mental health research and implementation of new health policies is growing. Furthermore, this design is recommended for physical therapy and rehabilitation research aimed at exploring and explaining complex phenomena in interaction with bio-psycho-social and personal factors. This study will explore the complexity of the interactions between motivation for PA, mental health, and traumatic experiences for which the use of a purely quantitative or qualitative approach would be insufficient.

Within mixed methods randomized controlled trials, a sequential explanatory design will be followed. In this design, qualitative results complement and help interpret quantitative findings. In order to address the main aims, a randomized controlled trial will be executed. CONSORT statement will be followed for reporting findings. Protocol will be submitted to clinicaltrials.gov. For addressing the secondary aim of the study, the study will follow a qualitative design based on interpretative phenomenology. Phenomenology is a model used for describing, understanding, and interpreting the lived experiences of the participants by means of discourse analysis.

Methods:

Members of Fire Stress Team (FiST) will be contacted, a non-profit community initiative aiming to increase awareness for support and care for first responders and their families, and Netwerk Brandweer Vlaanderen, the firefighters' network of the Flemish region of Belgium. Participants will be recruited via mail in which they will receive the participant information and a flyer of the study. Participants will have the option to schedule a meeting with the main researcher to go through possible questions or comments.

Participants should have internet access and an active Facebook account or be willing to create one. First-responders will be required to nominate a support partner. This may be any person with a close personal relationship to them, for example, partner, family member, carer or friend with whom they have at least weekly in-person contact with. Participants who are eligible will be randomized to either the lifestyle PA counselling or a wait-list condition.

To avoid separating firefighters from their support partner, each pair will be randomized as a unit. Each group will have the same number of participants (1:1). Each pair will be coded by a research assistant, who will do the simple randomization into control or intervention arm before baseline assessment using www.randomization.com. Allocation will be concealed from participants and the main researcher. The research assistant will introduce the allocation results in a sealed opaque envelope which will only be opened once baselines assessments have been completed in order to invite the participants to the Facebook group.

G*Power was used to detect an average large effect size (r = 0.8) with a statistical power of 80% and a significance level of 0.05 based on the SD of a similar population. A total sample size of 24 firefighters per group for each intervention study is required to detect a 10 point between group difference on the PCL-5. An additional number of 6 firefighters will be recruited to account for a possible drop-out rate of 22% based on the results of the latest literature on drop-out rates on exercise trials for anxiety and related- disorders.

Assessments will be executed on 3 time points for both intervention and control group: one-week pre- intervention, immediately post- intervention and 3 months post. The full survey takes approximately 50 minutes to complete. Data will be stored separately for control and intervention arm. A survey with all the questionnaires will be sent by e-mail to the participants. Blinding at baseline will be reached by concealed allocation, and a researcher blinded to group allocation will carry out assessments post-intervention and at 3-month follow-up.

The PA counselling intervention will consist of 10 weeks of content, delivered online interventions through a private Facebook page. Firefighters and their nominated support partners will both be encouraged to be actively involved on the Facebook page and with the programme. The research team will facilitate discussion boards. The intervention will be elaborated based on the evidence gathered in previous studies on the different motivation strategies and barriers for PA. Weekly content will include information regarding different aspects of physical activity and mental health, demonstration videos, links to existing online resources and discussion questions. These posts will all occur from the study generated account, twice a week, and the page will be checked by the researcher at least once per day, Monday to Friday. If participants are not interacting (i.e. reading the posts) in the Facebook page for more than a week they will be contacted by the main researcher. At the beginning of the intervention, participants will be given a Fitbit Inspire 2 in order to learn self-monitoring and goal-setting. An outline of the intervention content can be found in Table 1. Behaviour-change techniques will be incorporated into the program. Participants will also have the option to join a weekly group telehealth call via Skype for Business. The main researcher, a physiotherapist specialized in PA counselling in mental health, will lead the discussion and provide further education on the same weekly topic as the Facebook group for approximately 20-30 min. To encourage participation, there will be two telehealth group calls per week and participants can join either. Participants will be able to join in on the discussion, share their experiences, and ask questions. Participants allocated to the control group will be assigned to a waiting list and enter the Facebook Group after the last follow-up assessment. The control group will receive the same content but there will be no telehealth discussion calls.

Table 1. Content of the on-line intervention. Week Content

1. Welcome and introductions.
2. Goal setting and self-monitoring.
3. Sedentary behaviour and recommendation
4. Physical and mental health benefits of PA.
5. Barriers and motivations.
6. Mental contrasting.
7. Support
8. Aerobic exercise.
9. Resistance exercise.
10. Review program / congratulations.

Data analysis:

Statistical analyses will be run using IBM SPSS statistics version 27. Data will be tested for normality with the Shapiro-Wilks test. Differences in baseline characteristics between the two groups will be analysed by means of independent-samples t-tests or Mann Whitney U tests when appropriate for continuous variables, and Chi-square test for categorical variables. Pre-specified intention-to-treat analysis will consider participants randomly assigned to each group for inclusion in the analysis, using the base-line characteristics of non-completers to compare with participants who complete all follow-up assessments. Multivariate analysis of variance will be used to explore between-group differences (standard mean difference and 95% confidence intervals) immediately post-intervention and at 3-month follow-up for all outcome measures. Cohen's d will be used as an estimate of the effect size. Mediation analysis will be carried out in 3 steps. First, effects of the intervention on autonomous motivation and perceived social support (potential mediators) will be tested by regressing both variables into the treatment condition. Second, associations between changes in potential mediators and changes in PA levels and mental health outcomes will be assessed by regressing PA levels and mental health outcomes into treatment condition and potential mediators. Third, indirect effect will be estimated and tested for statistical significance by means of the Sobel test.

Qualitative analysis will be based on an Interpretative Phenomenological Approach. QRS Internationals' NVivo 12 software will be used to store and code the inductive qualitative data gathered from the focus groups. Interviews will be recorded and transcribed verbatim, and sent back to the participant to check veracity. In order to identify, analyse, and report patterns within data, thematic analysis will be used. The steps for thematic analysis are: 1) familiarisation with data, 2) generation of initial codes, 3) searching for themes, 4) reviewing the themes, 5) defining and naming the themes, and 6) producing the report. Trustworthiness will be ensured by team meetings to discuss the data. A research assistant will take the role of observer in the focus-groups and assist the main researcher with data collection and non-verbal observations.

Compliance and acceptability:

Will be defined by usage of the Facebook group (manual calculation of the sum of posts, likes and comments), and participant retention (completion of questionnaires and retention in programme). Acceptability will be assessed immediately post-intervention using the 14-item feasibility and acceptability questionnaire that has been used previously to measure participant responses to a private Facebook group.

Ethical considerations:

All participants will receive information concerning the purpose of the study, being properly stated in a consent form in Dutch. The protocol, patient data management plan, and consent form will be sent to the local KU Leuven Ethical Committee, and registered at clinical trial center (CTC) UZ Leuven prior to the start of the trial. To avoid potential loss of confidentiality, data collected will be anonymized and de-identified immediately after its collection. For qualitative focus groups, participants' names will be coded in a password-secured file by the main researcher. Participation in all studies is voluntary and participants will be able to withdraw at any time without any consequence or prejudice. Participation in the intervention study will not be reimbursed since monetary profit is a form of external motivation which might affect the outcomes of the intervention. Flyers showcasing the obtained results will be sent to the involved associations for their dissemination.

Participation in these studies has little to no associated risks. Participants that are confronted with strong emotions when filling in the surveys will be directed to local psychological services. There will be no direct human contact, implying no COVID-19 infection risk. All data collection will be carried out on-line, and post PA recommendations will be adapted to current local restrictions and recommendations (consulted in https://www.info-coronavirus.be/en/faq/).

Facebook group will be private and hidden for anyone not involved in the intervention. Participants will be encouraged to make anonymous posts when discussing sensible topics in the Facebook group. Anonymous posts are seen by every member of the group but only the group administrator will know the identity of the person posting it. Additionally, participants will have to sign a confidentiality clause in order to enter the group. During telehealth calls and focus groups, only the first name of the participants will be used.

Inclusion Criteria:

• 18-65 years old
• Physically inactive (less than 150 minutes of moderate to vigorous physical activity per week)
• Active as a firefighter
• At least mild symptoms of depression, anxiety or stress according to the DASS-21

Exclusion Criteria:

• Acute suicide ideation
• Unfit to engage in physical activity