A therapeutic exercise program for adolescents engaged in gender diversity services: study protocol for a non-randomised clinical trial

Trial design

The methodological objective of this pilot study is to conduct a non-randomised feasibility trial, using considerations for a type 2 effectiveness-implementation hybrid study [19]. This particular study design simultaneously evaluates the clinical effectiveness of an intervention and the feasibility or impact of its implementation within a real-world setting [19]. The primary outcomes will focus on intervention implementation, assessing aspects such as acceptability, appropriateness, fidelity of delivery, dose delivered, reach, and feasibility – encompassing accessibility, participant adherence, engagement, and satisfaction. These outcomes will be evaluated using data collected from program participants, their parents/carers, and the exercise physiologists delivering the intervention. Secondary outcomes are measures of quality of life, well-being, physical activity behaviour, and markers of physical health (e.g., muscle strength, cardiovascular fitness, body composition). Health outcomes will be assessed pre- and post-program with collection of feasibility data throughout program delivery. All participants will also be invited to participate in an interview at the end of the trial to share their experiences (e.g., “what was helpful or what could be improved”). See Figure 2 for the trial flow.

Figure 2:

Study flow chart.

Integrated consumer consultation and participation

This study was informed by the GENder idenTity Longitudinal Experience (GENTLE) Cohort Consumer Advisory Group. They represent participants of the GENTLE Cohort, a continuously recruiting longitudinal cohort of young people presenting to the Child and Adolescent Health Service, Perth Children’s Hospital Gender Diversity Service, aimed at tracking the longitudinal health outcomes of children and adolescents engaged with the service. The Consumer Advisory Group provided input twice to ensure the exercise program’s protocol and evaluation structure consider the lived experiences of trans adolescents. Qualitative feedback was also sought from trans young people, their families, and health professionals who are either engaged in specialist paediatric gender services or provide trans healthcare in Australia [20]. Throughout the program, trans young people, families, and exercise instructors will be asked to provide feedback, both informally and through formal measures such as evaluation satisfaction surveys. This feedback will inform ongoing refinements to the trial delivery, ensuring that reasonable adjustments are made to support trial implementation without altering the core research design. By collaborating with trans young people, families, and stakeholders, the research aims to create a consumer-guided safe and inclusive evidence-based exercise service, aligning with the Western Australian Mental Health Commission’s co-production plan and the idea that consumer involvement in healthcare research leads to better outcomes [21].

Study population and eligibility

All trial participants will be current patients (age 12–17 years) who are engaged with the Child and Adolescent Health Service, Perth Children’s Hospital GDS and who have consented to be part of the GENTLE Cohort (Child and Adolescent Health Service Health Research Ethics Committee RGS0000000320). The trial will run for 12 weeks in a series of community locations aiming for 20 participants.

Additional inclusion criteria are as follows:

1. All trial documentation including Information and Consent Forms have been produced in English only. Trial participants must have a sufficient command of the English language to be able to consent and have parent/carer consent to participation.

2. Participants must be willing and able to attend in-person group exercise sessions at a designated trial location, and complete pre- and post-intervention assessments at the School of Human Sciences, University of Western Australia, Crawley campus.

Exclusion criteria are as follows:

1. Participants will be excluded if they are unable to safely participate in exercise based on the Pre-Exercise Screening System for Young People (PSS-YP) [22] tool and initial assessment subjective interview questions with the young person and/or their parent/carer. Exclusion from the trial based on the above medical screening includes medical contraindications to exercise (e.g., unstable or untreated cardiac condition, medical instability due to eating disorder, and/or non-compliance with current treatment recommendations

2. If potential contraindications to exercise are identified during the initial assessment or screening process (e.g., acute mental health condition), the exercise professional liaises with the participant’s treating medical team (i.e., General Practioner, psychiatrist, paediatrician) to seek clarification or written medical clearance. If a clinical risk is newly identified, the participant is referred for appropriate assessment and support in coordination with their GDS team and primary care provider.

3. If a young person presents with signs of clinical deterioration, such as recent non-suicidal self-injury wounds, substance use, or non-compliance with treatment, they may need to be temporarily excluded from individual sessions on safety grounds. However, this does not automatically result in exclusion from the entire trial. Ongoing clinical clearance (e.g., regarding recent non-suicidal self-injury) will be sought as needed.

Recruitment

Recruitment methods will include flyers for clinicians to hand out to eligible adolescents during clinic visits and/or via email invitation sent by the GDS Senior Research Officers including Participant Information and Consent Forms, to adolescents identified by their case managers as eligible. Young people known to have a current severe eating disorder will not be invited to participate. Trans adolescents and/or their parents/carers who express an interest by responding via email/telephone call will be placed on a mailing list to receive further details regarding the trial by the lead author. If trans adolescents are ineligible to participate in the trial (e.g., due to age limitations or geographical constraints), the research team will refer the young person to alternative exercise services within Western Australia.

Parents/carers of movement program participants will be invited to participate in the research project evaluation at the same initial contact timepoint as their children. At this timepoint, they will be provided with a detailed Parent/Carer Information Sheet and Consent Form that outlines the purpose of the research, what participation involves, and their rights as participants. Their involvement will primarily consist of completing an evaluation survey via and/or participating in a face-to-face semi-structured interview focused on their perspectives regarding their child’s engagement in the movement program, perceived impacts, and any observed barriers or facilitators to participation (see supplementary material The Movement Program Interview Guide).

Similarly, exercise instructors facilitating the trial will be invited to participate in the research project evaluation. They will be given the Exercise Instructor Information and Consent Form to read, complete and sign. Their involvement will primarily consist of completing an online evaluation survey at the same time points as movement program participants and parents/carers. Instructors will also be invited to participate in a face-to-face semi-structured interview following completion of the intervention, focused on their experiences delivering the program, observations of participant engagement, and perceived barriers or enablers to implementation (see supplementary material The Movement Program Interview Guide). Both parents/carers, and exercise instructors will be notified that their decision to participate in the project, or not participate, will not impact their involvement with the GDS, other health services, or other research partners.

Withdrawal of the study participants

Participants may withdraw from the trial at any time, either verbally or in writing. Withdrawal may relate to either the research component (i.e., data collection and evaluation) and/or the intervention component (i.e., participation in the exercise program). Participants who choose to withdraw from the research component may still continue to take part in the movement program if they wish, and this option will be clearly communicated during consent. Conversely, if a participant withdraws entirely – meaning both from the research and the movement program – they will be replaced by individuals on the waitlist where possible. In cases where a participant withdraws and their parent/carer has consented to participate in data collection, the parent/carer will also be notified that their involvement is no longer required, all data will be destroyed and not be used for evaluation purposes. The right to withdraw and its implications are clearly outlined in the participant information sheets and consent forms and will be reiterated during the consent process. All instances of withdrawal, including timing, participant characteristics, and stated reasons, will be systematically recorded and reported as part of the feasibility analysis.

Exercise program design

The movement program has been designed based in collaboration with the GENTLE Community Advisory Group, and a qualitative exploration of trans young people, and their families, and health professionals specialising in gender diversity (i.e., general practitioners, psychiatrists, psychologists, social workers, research officers, exercise physiologists) [20]. The movement program is also informed by research and guidelines for commonly reported health considerations in trans adolescents presentations (e.g., anxiety, depression, eating disorders, body and gender dysphoria, neurodivergence, suicide ideation, non-suicidal self-injury) [1], 2], 9], 22], the World Health Organization (WHO) physical activity guidelines for children and adolescents [23], and the Frequency, Intensity, Time, and Type (FITT) principles which serve as a foundational framework for the prescription and progression of exercise to support health outcomes in youth populations [24]. Current WHO guidelines recommend an average of 60 or more minutes of moderate to vigorous intensity physical activity each day for children aged 5 to 17, as well as activities to strengthen muscle and bone at least 3 days a week [23]. In addition to traditional sport and exercise, the program design explores the broader, more flexible concepts of physical activity, such as active recreation, which has been reported to be an important coping strategy for people experiencing minority stress [25].

All participants will be encouraged to engage in health-promoting physical activity in alignment with WHO and Australian national recommendations [23]. To support this, movement program participants will have the option to engage in a personalised home exercise program prescribed by the lead exercise physiologist at their movement program sessions. This optional home program provides structured guidance for those who wish to incorporate additional home-based exercise to enhance physical activity motivation [15].

The movement program will be held at local community recreational spaces, including indoor (e.g., halls) and outdoor spaces (e.g., ovals). These venues will be carefully set up to prioritise the engagement, and wellbeing of trans young people, ensuring a safe and inclusive environment [2], 5]. Creating a safe and inclusive space may include removing or covering mirrors, displaying LGBTQIA+ affirming signage, providing all-gender bathroom access, and offering orientation and inductions to help participants feel comfortable and supported in the space. Additionally, the chosen locations are geographically spread to support participant accessibility to the program locations.

Participants will attend one supervised group movement session per week for 12 consecutive weeks (frequency). Each session will run for 60 min (time). Each movement session will include a variety of elements, described below, and can be tailored for individual differences, needs and abilities (type). A warm-up and check-in will be undertaken to prepare the participants for physical activity and allow for exercise modifications or limitations. Following the warm-up, cardiorespiratory fitness activities that elevate heart and breathing rates (e.g., running, dancing, or aerobic fitness games), muscular strength exercises targeting strength and endurance of various muscle groups using free weight equipment or bodyweight (e.g., push-ups, squats, planks), and sport skill development or games to assist team building and socialisation (e.g., soccer, pickleball, or floorball) will be delivered. The program’s activities are designed to be adaptable, with exercises that can be progressed and/or regressed to suit varying age groups and abilities, ensuring all participants are both engaged and appropriately challenged. Progression may include increased duration of ctivity, greater resistance, or more complex movements (intensity). To address these differences, participants may be grouped into smaller cohorts based on similar emotional and physical developmental stages, while the movement program remains flexible, occasionally mixing age groups to foster inclusivity, peer learning, and targeted developmental support.

The intended number of participants is 20 young people. A maximum group size of 10, and minimum size of 3 has been determined to ensure the group can be well-facilitated by two exercise physiologists from Thriving in Motion, a community-based, not-for-profit exercise provider with experience working with marginalised youth, including trans young people. A facilitator’s manual for the exercise instructors has been developed by the research team, outlining session plans and the procedures detailed in the protocol to ensure fidelity in the delivery of the intervention. The facilitator’s manual can be accessed by contacting the corresponding author.

Exercise instructors

The trial exercise instructors are Accredited Exercise Physiologists, university-qualified allied health professionals in Australia, holding a master’s-level qualification in clinical exercise physiology. They will receive specialised training to work effectively with trans adolescents and their families. This training includes Youth Mental Health First Aid [26] and tailored inclusive trauma-informed exercise practices. The training has been developed by clinical exercise physiologists and mental health professionals with expertise in gender diversity, adolescent development, and trauma-informed care. It covers affirming communication, safe and inclusive exercise environments, understanding the impact of minority stress and trauma, and strategies to support emotional regulation, autonomy, and psychological safety in movement settings.

Their training will equip them to support the wellbeing and exercise participation of young people who have a range of mental health conditions (e.g., anxiety, depression, suicidal ideation, non-suicidal self-harm), understand adolescent development, and navigate group dynamics and challenges related to social, emotional and behavioural differences. The exercise instructors are also equipped to support neurodivergent individuals, those with co-occurring physical health conditions, and participants experiencing disordered eating and/or exercise behaviours. Alongside their comprehensive training, the exercise instructors will have access to participants’ health screening and physical health assessment reports prior to the movement program commencing in order to tailor the exercise activities to meet the needs of participants.

Outcome measures

Retention

To maximise participant retention and reduce loss to follow-up, assessments will be scheduled according to participant preference and availability as much as possible. Appointment reminders will be sent out one week and one day prior to assessment date. Contact will be made immediately following a “no-show” to an assessment or movement program session to record reason and reschedule within the timeframe for the study protocol. To encourage attendance to the post-trial assessments, a comprehensive report will be provided to families upon completion of the final assessment.

Timing

Measures will be assessed at baseline (pre-trial) and within one week following completion of the trial, to reduce the risk of detraining and to more accurately capture the immediate effects of the intervention.

Statistical analysis

All quantitative data will be analysed using Microsoft Excel and IBM Statistical Package for the Social Sciences (SPSS) Statistics software. Data will be screened for completeness and missing values. Participants missing entire datasets (e.g., all physical health assessment data) will be excluded from relevant analyses. For pre–post comparisons, if more than 5 % of data are missing for a given outcome, multiple imputation by chained equations (MICE) will be considered to minimise bias and preserve statistical power. The imputation model will include key demographic variables (e.g., age, sex assigned at birth), and all available outcome variables. Ten imputed datasets will be generated, and results will be pooled to produce final estimates, consistent with standard procedures for small-sample trials. A 50 % intervention adherence rate will serve as the inclusion threshold to help isolate intervention effects, reflecting our preliminary aim to assess the need for a full-scale randomised control trial. An adherence level of ≥50 % is considered sufficient to indicate initial engagement with the intervention, while also accounting for common barriers to full participation within adolescent mental health and gender-affirming care contexts, both characteristic of this cohort. This threshold reflects a pragmatic balance between feasibility and meaningful exposure to the program. We will also conduct sensitivity analyses using higher adherence thresholds (e.g., 75 %) to explore whether intervention effects vary by level of participation. These analyses will help assess the robustness of findings and inform the optimal intervention dose for future trials. Descriptive statistics will be used to summarise pre-to-post-program differences. The magnitude of change in health outcome variables (i.e., physical health, well-being, and quality of life) from baseline to program completion will be assessed by calculating Cohen’s d effect sizes with correlations between the variables. In addition to effect sizes, the clinical significance of changes in health outcomes measured by the SF-12 and WHO-5 will be evaluated using minimum important difference (MID) thresholds or reliable change indices, where available. Given the exploratory nature and small sample size of this trial, formal hypothesis testing will not be conducted. The sample size for this study is in keeping with similar trials [15]. Given the novelty and intent of the intervention, findings will provide valuable insight into the health outcomes, the most effective operation of the movement program, and inform design of future trials and research in this field.

Interviews will be conducted by the research team, who have experience in qualitative research methodology, including interviewing marginalised young people, families, and health professionals. Participants will guide the interview, with probing questions used for clarification and exploration [43]. At the end, participants can ask questions, offer additional information, and provide feedback. Pragmatic considerations (e.g., time and resource constraints) will guide data collection, and we aim to collect sufficient, appropriate information to address our research questions and construct a comprehensive story through our data. We will adopt an inductive reflexive thematic analysis approach [44], 45]. A ‘critical friends’ process will be employed, with co-authors providing feedback on meaning units, themes, and interpretations [46]. Collaborative processes may result in themes being merged, redefined, or recoded based on collective interpretation, ensuring rigor and quality in analysis [47]. Reflexive thematic analysis is a cyclical and iterative process, and various stages of the analysis process will be repeated or returned to.

Data management

All data will be coded, backed-up and securely stored on servers at the University of Western Australia (UWA) which are password and algorithm protected. Any hard copies relating to collection of data will be stored in locked filing cabinets on site at UWA in the School of Human Sciences (Exercise and Sport Science) and as per UWA standard practice, will be retained for 7 years following publication or until the youngest participant turns 25, whichever is longer. Regarding completion of outcome measures, participants will be given a unique identifier code to record on the measures each time instead of using identifying details. Identifying information and research data will be stored separately. Data will be de-identified for entry and analysis in both SPSS and NVivo. Regarding qualitative data, audio recordings will be stored on a secure server and will only be accessible to the named investigators. Transcripts will be de-identified and stored on NVivo software and will only be accessible to the named investigators. All SPSS and NVivo data will be accessible only to the named investigators and will be password protected.

Once the minimum retention period for our dataset has been reached, the University’s Records, Archives & Digitisation Services team will ensure there are no current Freedom of Information or other outstanding actions on the records before initiating the destruction approval process, as per Western Australian University Sector Disposal Authority standard practice.

Possible harms and safety monitoring

While there are minimal risks associated with participation, some discomfort may occur during pre- and post-exercise tests, such as leg fatigue, or increased heart rate or breathing rate. These are typical responses, and participants can stop any test or activity if they feel uncomfortable. Additionally, a small amount of ionizing radiation via DEXA scans is required for this study, and this information is also included in the participant information and consent form. If participants experience distress during assessments, group sessions, or interviews, they can seek immediate support from the trial facilitators. Contact information for external support services (e.g., Qlife, Lifeline, Kids Helpline) will be provided to participants. Participants will also be reminded that they can reach out to their treating team for additional support.