Longitudinal study of open goals in physical activity promotion: protocol for ‘Open to Move’

Abstract

Open goals (eg, ‘see how many steps you can reach today’) have developed as a promising strategy for increasing physical activity and producing beneficial psychological outcomes such as autonomous motivation, enjoyment and confidence. However, it is not yet clear what the long-term outcomes of open goals are, what factors moderate their use or whether/how individuals transition away from open goals. Therefore, in this study (‘Open to Move’), we aim to understand the mechanisms that explain why, when and for whom open goals are beneficial in promoting and maintaining physical activity. ‘Open to Move’ is a 12-month, exploratory, mixed-methods longitudinal study involving healthy adults aged 18–69 in Australia. Participants will receive a walking programme based on open goals via a mobile app and website, which will also provide feedback on their step counts and fortnightly one-to-one meetings online for the first 6 months. The outcomes will be measured using self-report surveys, interviews, recorded step counts on a mobile phone and process evaluation. The study is ongoing, and 81 participants have commenced thus far, with a target of 210 participants. We expect to conclude recruitment by August 2025 and anticipate that data collection will be completed by August 2026. This study will develop an understanding of the long-term outcomes of open goals, moderating factors and transitions to other goal types—providing important insights for developing a programme theory that can inform full-scale testing and implementation of open goals within physical activity interventions in future.

WHAT IS ALREADY KNOWN ON THIS TOPIC

• Open goals are a promising strategy for increasing physical activity and producing positive psychological outcomes. However, the long-term outcomes of open goals, what factors moderate their use and whether/how individuals transition away from open goals remain unclear.

WHAT THIS STUDY ADDS

• This study will provide insights into the mechanisms that explain why, when and for whom open goals are beneficial in promoting and maintaining physical activity through a 12-month, exploratory, mixed-methods longitudinal study involving healthy adults.

HOW THIS STUDY MIGHT AFFECT RESEARCH, PRACTICE OR POLICY

• This study will inform full-scale testing and widespread implementation of open goals within physical activity research, practice and policy.

Goal-setting is one of the most commonly used intervention strategies to promote physical activity. For example, in a review of physical activity interventions and behaviour change techniques for healthy inactive adults,¹ goal setting was identified as the most frequently used strategy, featuring in 84.6% of studies. In addition to being popular, goal-setting is also an effective strategy for increasing physical activity: a meta-analysis² found that goal-setting interventions had a medium effect size (d=0.55, 95% CI 0.43 to 0.67) on physical activity, based on 52 interventions within 45 studies. It is typically assumed that goals should be specific to be effective and, as such, physical activity goal-setting is typically based on specific performance goals, for which the individual’s focus is on a specific task outcome, with common examples including goals to reach 1500 steps more than yesterday; to reach 10 000 steps per day or to reach a target number of minutes of physical activity each day/week (such as 30 min of moderate-intensity physical activity per day). However, the meta-analysis mentioned above² found that goals were effective for increasing physical activity regardless of whether they were specific or non-specific/vague (eg, ‘to be more active’). That finding prompted a series of critiques that question whether we need to reconsider best practice in goal setting for physical activity promotion^{3 4}, including suggestions that the use of specific performance goals could potentially pose risks or negative outcomes—such as stress, pressure, guilt, anxiety and perceptions of failure—to those who are least active and need most support.³ Indeed, it has also been highlighted that ‘what remains to be understood at this point is why vague goals result in comparable physical activity effects/benefits to specific goals’⁴ (p9).

Open goals are defined as ‘non-specific and phrased in an exploratory way, with measurable parameters, producing graded (rather than succeed-or-fail) outcomes’⁵ (p8), such as to ‘see how many steps you can reach today.’ Since they were first reported in 2016, there has been a series of nearly 20 qualitative, mixed-method and experimental studies on open goals, particularly in the context of physical activity promotion (see Swann et al⁵ for a review). This evidence has revealed that open goals are a promising strategy for increasing physical activity, and they have been found to increase various positive psychological outcomes, including interest, intentions and motivation for future engagement, optimal perceived challenge, increased confidence, autonomy and enjoyment.⁵

Despite promising initial findings, there are several important critiques of research on open goals to date that are important to resolve to facilitate real-world implementation. First, the experimental evidence for open goals to date is largely based on brief (eg, single-session) studies that have tested open goals in a laboratory setting, for example, using the 6 min walk test.⁶ While these studies have generated important insights, larger-scale, long-term research is needed to understand how to optimise the use of open goals in preparation for broad dissemination and implementation. Second, it is unclear for whom open goals are most (and least) beneficial. Hawkins et al⁶ found that insufficiently active individuals completed significantly more physical activity when pursuing open goals rather than specific goals. Conversely, more active individuals completed significantly more physical activity pursuing specific goals than open goals.⁶

Furthermore, there is uncertainty over factors that moderate the adoption of open goals. For example, in a 10-week feasibility study of a walking programme based on open goals, Goddard et al⁷ reported that some participants responded well to open goals while others did not (eg, some set specific goals instead) and suggested that future research should aim to understand factors influencing participants’ readiness or suitability for pursuing open goals. Third, Goddard et al⁷ identified that some individuals transition away from open goals (eg, they start pursuing self-set-specific goals after pursuing open goals for several weeks). However, it is currently unclear how, why or when individuals transition, each representing dynamics important to understand in the context of integrating open goals into real-world physical activity programmes.

Aims

According to prominent intervention development and implementation frameworks⁸, a crucial initial step is to develop a programme theory that describes the mechanisms through which an intervention is expected to lead to its effects and under what conditions. Best practice is to develop the programme theory prior to full-scale testing of the intervention and subsequent implementation.⁸ Therefore, an important next step in research on open goals in physical activity settings is to conduct a larger-scale, longer-term study that provides evidence to inform the development of a programme theory of open goals in preparation for full-scale testing (eg, a randomised controlled trial comparing open goals with existing physical activity programmes based on specific performance goals), implementation and scaling. The aims of this project are exploratory in that we seek to describe and understand the mechanisms that explain why, when, and for whom open goals are beneficial in promoting physical activity (via a walking programme). Specifically, to provide evidence that informs the development of a programme theory, this project will address a series of exploratory research questions:

• RQ1: What are the effects of open goals on physical activity across 12 months?

• RQ2: What demographic, physical activity and dispositional factors determine appraisal of and commitment to open goals initially and across time?

• RQ3: What demographic, physical activity and dispositional factors explain differences in the associated change of commitment to open goals on physical activity?

• RQ4: What motivational processes mediate the effects of open goals on physical activity?

• RQ5: How and why do individuals transition from open goals to other goal types?

• RQ6: What are the trajectories with which individuals transition from open goals to other goal types across time, and do they differ as a function of demographic and dispositional variables?

• RQ7: What are the physical activity trajectories with which individuals transition from open goals to other goal types, and does it differ as a function of engagement with the intervention and type/consistency of goals used?

• RQ8: What motivational, affective, cognitive and well-being outcomes are associated with each goal trajectory?

• RQ9: What is the optimal way of prescribing open goals (eg, in terms of timeframe)?

Method

Design

In line with recommendations to preregister exploratory research to make it more trustworthy and useful,⁹ this project was registered with the Open Science Framework (https://osf.io/gsej7/) in December 2024. In this project (‘Open to Move’), we will conduct a 12-month, single-arm, exploratory, mixed-method, longitudinal study.^{10 11} This design is recognised as a suitable approach to the study of dynamic phenomena,¹¹ such as individuals’ adoption, maintenance and/or transition from open goals. It can address how, when and why change occurs.¹⁰ An exploratory approach will be adopted in line with the project’s aims (ie, to generate hypotheses/develop a programme theory for future testing). A single-arm approach will be adopted in line with intervention development frameworks⁸, which suggest that the development of a programme theory should occur prior to full-scale testing (eg, in a randomised controlled trial) and implementation. A ‘fully longitudinal’ mixed-methods approach will be adopted, which involves collecting both qualitative and quantitative data throughout the project.¹⁰ A mixed-method approach will be adopted to enable qualitative investigation of participants’ experiences of pursuing open goals and transitioning to other goal types—in addition to assessing quantitative outcomes. Mixed-methods, multiple case studies¹² will be embedded within the project design to enable rich, detailed insights into particular issues, such as how and why individuals transition from open goals to other goal types.

Participants and sampling

Based on purposive sampling, eligible participants will be recruited via several strategies, including media releases, social media advertisements and email distribution lists via project partners. Snowball sampling will also be used. Interested individuals will be directed to the project’s website (www.opentomove.com.au), where they can express interest. Table 1 provides an overview of the inclusion/exclusion criteria. Participants will be excluded if they: (1) do not own a mobile phone that records step counts or is not compatible with the project’s website/mobile app; (2) have a musculoskeletal injury that impacts their walking gait; (3) are deemed high risk for cardiovascular, metabolic or pulmonary disease according to the adult pre-exercise screening system¹³ or (4) if they are currently engaging in another physical activity programme. Participants’ level of physical activity will not be an exclusion criterion as it may be a moderator of open goals.⁶ Therefore, we will aim to recruit a diverse range of physical activity levels at baseline.

Table 1. Inclusion criteria for Open to Move.

Participants will be eligible if they are:	Adults aged 18–69 years
	2 1Fluent in English
	3 1Reside in Australia
	4 1Own an Android or Apple smartphone
	5 1Can access to online video calls through Zoom software
	6 1Can walk without the need of assistance
	7 1Do not have a known disease and/or signs or symptoms of disease or are at a higher risk of an adverse event due to physical activity/exercise according to stage 1 of the Exercise and Sports Science Australia Adult Pre-Exercise Screening System

We will stop data collection when we have recruited 210 participants. This sample size was determined based on the estimated power required to analyse the trajectories of goal types. Cluster trajectory analyses¹⁴ require valid measures of change over time (ie, regular repeated assessments of participants’ goals). Given that most trajectory cluster analyses are based on between 1 and 3 parameters,¹⁵ we conservatively estimate a required sample size of 210 participants. Simulated power analyses for generalised linear mixed models estimate that the sample size of N=210 will allow sufficient power to test the anticipated small effects of how within-person change in goal types is associated with concurrent and prospective psychological outcomes with 50 repeated measures.¹⁶ Small effects are anticipated, given that they are common in motivation-adherence literature.¹⁷ All participants will complete the same protocol, so the only variations in data at each time point will be due to adherence/dropout and fidelity.

When reporting qualitative or mixed-methods components, the size of our subsamples will be based on the data available (eg, it is expected that there will be fewer participants/less data at the end of the study than at the start); the concept of information power¹⁸ for qualitative components; and Stake’s¹² recommendation of a minimum of 4 and maximum of 10 cases for mixed-methods multiple case studies. Whereas the focus of our quantitative component is generalising, the emphasis in the qualitative component of our mixed-methods research is to provide in-depth descriptions. Thus, the sample sizes will be unequal, with the qualitative component sample size being smaller and determined in line with guidance for information power.¹⁸

Procedure

After participants express interest, they will be screened and included, excluded or asked to provide further details (such as a GP referral letter). Eligible participants will then be asked to provide informed consent, and an initial meeting (week 0—see below) will be organised.

Open to Move will consist of a 12-month online step count intervention based on open goals. Participants will receive a walking programme based on open goals, supplemented by a mobile app and website (www.opentomove.com.au) that provides reminders, tracks participants’ step counts and collects survey data. The mobile app will be available to download from the Apple and the Google Play Store, and it will remind the participant of their daily/weekly open goal, present their daily, weekly and overall step counts, as well as include a link to complete surveys. Participants will also be offered fortnightly one-to-one meetings (30 min each via Zoom) during the first 6 months, whereby trained data collectors (Postdoctoral Researchers, PhD students and Research Assistants) will provide individualised goal-setting support to the participants and answer any questions. These meetings will be recorded and will incorporate event-focused interviews (ie, with a focus on the prior 2 weeks of physical activity¹⁹) in which participants will be asked to reflect on the goals they have pursued, their progress and whether they maintained open goals or changed/want to change to a different type of goal. The fortnightly meetings will conclude after 6 months to enable monitoring of how participants respond when support is withdrawn. Table 2 provides an overview of the procedure for each week of the study.

Table 2. Overview of study procedure.

Week(s)	Procedure
Week 0 (baseline)	60 min online one-to-one meeting with a researcher via Zoom
	Provide overview of the study and its requirements, and confirm consent Provide instructions on how to download and log in to the Open to Move mobile-app. Complete Week 0 surveys (see table 2). Record interview discussing participant’s physical activity history, current physical activity levels, goal-setting experience and goal-setting knowledge. Provide baseline instructions: to complete their normal amount of physical activity for the next week and to carry their mobile phone as much as possible each day. Organise the next online meeting 1 week later. Participant will receive an email reminder prior to that meeting.
Week 1	60 min online one-to-one meeting with a researcher via Zoom
	Recap baseline instructions and check step count data from previous week. Provide information on safety considerations while engaging in physical activity. Complete week 1 surveys (see table 2). Introduce and explain open goals, and provide open goals for the programme on a daily/weekly basis (‘see how many steps you can reach each day this week’) and for the programme overall (‘see how active you can be’). Record interview on participant’s understanding and appraisal of open goals, with verbal manipulation check to ensure participants do not conflate open goals with other goal types. Organise the next online meeting 1 week later. Participant will receive an email reminder prior to that meeting.
Weeks 2–25	30 min online meeting with a researcher via Zoom every fortnight (ie, every second week between weeks 2 and 24)
	Complete relevant week’s surveys (see table 2). Record event-focused interview on the participant’s experience of pursuing open goals and reflections on progress/efforts to increase physical activity since the last meeting. Organise the next online meeting in 2 weeks. Participant will also receive reminder via email prior to that meeting. If participants are unable to attend fortnightly meetings, they will be asked to complete the survey data for that week via the app instead.
	Brief self-report survey every fortnight (ie, every second week between weeks 3 and 25)
	Complete relevant week’s surveys (see table 2). Participant will also receive reminder via SMS when survey is ready to complete. Survey completion via the app will also sync participant’s step count data.
Week 26	60 min online one-to-one meeting with a researcher via Zoom
	Complete Week 26 survey measures (see table 1). Record interview reflecting on participant’s experience of the programme, their perceptions of open goals, and their engagement in physical activity. Explain the next phase of the programme (see below) which will not involve the fortnightly one-to-one meetings. Participants will receive a US$20 gift voucher as an honorarium.
Weeks 27–51	Brief self-report survey every week
	Participants will no longer be provided with fortnightly one-to-one meetings—to assess engagement with open goals after support is withdrawn. Participants will still have access to the app. Complete relevant week’s surveys (see table 2). Participant will receive reminder via SMS when each week’s survey is ready to complete. Survey completion via the app will also sync participant’s step count data.
Week 52	60 min online one-to-one meeting with a researcher via Zoom
	Complete Week 52 survey measures (see table 1). Record interview reflecting on participant’s experience of the programme, reflections on the previous 6 months after one-to-one meetings were withdrawn, and their intention to use open goals moving forward. Participants will receive a US$20 gift voucher as an honorarium.

SMS, short message service.

Measures

This project will use self-report surveys, interviews and mobile phone-recorded physical activity (step count) data. Table 3 provides an overview of the measures that will be taken at each time point. Process evaluation measures will also be taken during this study.

Table 3. Overview of methods and measures.

Methods	Measures/approach		Items/length	Time point/week(s)
Screening and demographics	Eligibility questions: Age Mobile device Residing in Australia Able to walk without assistance Participation in any other physical activity programmes Access to video calls via Zoom software Fluent in English Contact details		10	EOI
	Adult pre-exercise screening system–stage 1		6	EOI
	Demographics: Date of birth Gender Nationality Dependents Occupation Postcode Make and model of mobile device Use of any other wearables (if so, make and model of other wearable)		9	0
	Demographics: Occupation Postcode Weight Height		4	26, 52
	Adult pre-exercise screening system–stage 2		13	0
Self-report surveys	International Physical Activity Questionnaire–Short Form		7	0, 26, 52
	Physical Activity Stages of Change Questionnaire		4	0, 26, 52
	Goal Orientations in Exercise Measure		10	0, 26, 52
	Behavioural Regulation in Exercise Questionnaire 3–6		6	0, 26, 52
	State Self-Control Capacity Scale		3	0, 2, 4, 6, 8,10, 12, 14, 16, 18, 20, 22, 24, 26, 52
	Perceived Variety in Exercise scale		5	0, 26, 52
	Perceived Environment questionnaire		7	0, 26, 52
	Task Complexity Scale		4	0, 26, 52
	The Curiosity and Exploration Inventory-II		10	0, 26, 52
	Basic Psychological Needs in Exercise Scale (Autonomy subscale)		4	1, 2, 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24, 26, 52
	Intrinsic Motivation Inventory (Interest/Enjoyment and Pressure/Tension subscales)		12	1, 2, 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24, 26, 52
	Physical Activity Enjoyment Scale–8 Item		8	1, 2, 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24, 26, 52
	Affective Exercise Experiences Questionnaire (Core Affective Experience subscales)		12	1, 2, 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24, 26, 52
	Self-Report Behavioural Automaticity Index		4	1, 2, 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24, 26, 52
	Exercise Self-Efficacy Scale		10	1, 2, 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24, 26, 52
	Mental Health Continuum (Emotional and Psychological Well-being subscales)		9	1, 2, 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24, 26, 52
Goal-related items	Commitment to baseline instructions		1	0, 1
	Goal acceptance: ‘To what extent do you accept the goal?’		2	1
	Goal self-efficacy: ‘How capable do you feel of accomplishing this goal?’		2	1
	Goal attractiveness: ‘How attractive is this goal to you?’		2	1
	Goal commitment: ‘How committed are you to this goal?’		2	1
			1	2–52
	Goal challenge: ‘To what extent is the goal demanding and challenging to you?’		2	1
	Goal pursued: ‘Did you follow this goal last week?’		2	1–52
	Goal progress: ‘How much progress do you feel like you made towards your goal last week?’		2	1–52
	Intentions to be active		1	1–52
Interviews	Baseline	Previous experiences of physical activity Knowledge, experience and preferences regarding goal setting	30 min	0
	6/12 months	Experiences, reflections and perspectives on the programme	30 min	26, 52
	Event-focused (fortnightly - weeks 2–24)	Perceptions of open goals; experiences of pursuing open goals and/or transitioning to other goal types	15 min	1, 2, 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24
Step count	Recorded by synchronising between the participant’s mobile phone and the project’s app/website each time they log in		N/A	0–52
	Percentage of weekly steps recorded by phone		1	1, 26, 52

EOI, expression of interest; N/A, not available.

Self-report survey data

Self-report survey data will be collected to assess participants’ responses to demographic variables, potential moderating factors, potential mediating factors and potential outcomes of open goals. These measures will be taken via the project’s mobile app and/or website. Table 2 provides more detail on the timing of each survey, and more information about each self-report survey is presented in online supplemental file 1.

Participants will be asked a series of questions when they express interest to assess their eligibility, including the Adult pre-exercise screening system—stage 1.¹³ Once they are included in the study, a series of demographic questions will be asked regarding date of birth; gender; nationality; dependents; occupation; postcode; make and model of mobile device; use of any other wearables (if so, make and model of other wearable); and the APSS—stage 2.¹³

To assess potential moderators of open goals (ie, factors influencing the extent to which open goals are adopted), participants will be asked to respond to a series of surveys: International Physical Activity Questionnaire—Short Form²⁰; Physical Activity Stages of Change Questionnaire²¹; Goal Orientations in Exercise Measure²²; Behavioural Regulation in Exercise Questionnaire 3–6²³; State Self-Control Capacity Scale (Ciarocco N, unpublished mauscript, 2007); Perceived Variety in Exercise questionnaire²⁴; Perceived Environment questionnaire²⁵; Task Complexity Scale²⁶; the Curiosity and Exploration Inventory-II²⁷; and the Mental Health Continuum (emotional and psychological well-being subscales).²⁸

To assess potential mediators of the relationship between open goals and physical activity adoption and maintenance, participants will be asked to answer the following surveys: Basic Psychological Needs in Exercise Scale (autonomy subscale)²⁹; Intrinsic Motivation Inventory (interest/enjoyment and pressure/tension subscales)³⁰; Physical Activity Enjoyment Scale–8 Item³¹; Affective Exercise Experiences Questionnaire (core affective experience subscales)³²; Self-Report Behavioural Automaticity Index (automaticity subscale)³³ and the Exercise Self-Efficacy Scale.³⁴

Each week, participants will be asked to respond to a series of single-item measures relating to their goal pursuit. Brief measures will be necessary given this study’s 52-week longitudinal design (see table 3). These single items will measure goals pursued, goal acceptance,³⁵ goal self-efficacy,³⁶ goal attractiveness,³⁷ goal commitment,³⁶ goal challenge,³⁶ goal progress³⁶ and intentions to be active.³⁸

Step count data

Step count will be collected via participants’ mobile phones, which will be synchronised with the project mobile app/website as a secondary outcome. This reflects a ‘real-world’ approach to measuring physical activity, which aligns with the translational nature of this research project (ie, seeking to advance open goals towards broad population-level dissemination). This approach has been considered a valid approach to measuring step counts. However, it has been noted that caution should be taken as mobile phone use can underestimate participants’ accumulated steps (eg, when not carried out³⁹). We will do validation checks at baseline, 6 months and 12 months, whereby we will incorporate assisted recall about the past week’s step count with participants during the interviews. We will perform sensitivity analyses in relation to all hypotheses tests, including physical activity, by recalculating the physical activity outcome and adjusting for estimated missed steps. The adjusted weekly outcomes will be the sum of that week’s step count and an individual-specific constant per week based on the estimated percentage of steps not captured by the participants’ wearable devices throughout the week. If our data allow, we may also do sensitivity analyses with a subsample of participants who also wear wearable activity/step trackers (eg, watch/ring) to check the concurrent validity of their tracker-recorded activity and their step count outcomes.

Interviews

All one-to-one meetings with participants via Zoom will incorporate semistructured interviews. Interviews at baseline (week 0) will seek to understand participants’ previous experiences of exercise and physical activity, as well as their knowledge, experience and preferences for goal setting. Interviews after 6 months (week 26) and 12 months (week 52) will seek to understand participants’ experiences, reflections and perspectives on the Open to Move programme. These interviews will be embedded within 60 min meetings with participants, in which they will also complete survey items via the app/website, and the interviews are expected to last up to 30 min, on average.

Event-focused interviews focus on the activities occurring within a recent timeframe¹⁹ and will be used for each one-to-one session via Zoom offered fortnightly between week 2 and week 24 to understand participants’ experiences of pursuing open goals and/or transitioning to other goal types. These event-focused interviews will be embedded within the 30 min meetings with participants, in which they will also complete survey items. This means they are expected to last up to 15 min on average across the 12 fortnightly 30 min meetings between weeks 2 and 24. All interviews will be recorded via Zoom and transcribed verbatim afterwards using transcription software (eg, otter.ai).

Process evaluation

Process evaluation data will be collected via record keeping (including session checklists to be completed during/after each meeting with participants) and will include seasonality; type of mobile device used; type of wearable device used (if owned); the number of meetings attended; duration of meetings; time between meetings; number of weekly and fortnightly surveys completed and dropout/retention. Fidelity checks will also be conducted via checklists completed by research staff during/after participant meetings to ensure consistency between interviewers, and transcripts of interviews will also be checked to enhance rigour and consistency.

Analyses

Statistical analyses

For statistical analyses, all data management and analyses will be conducted using the latest available version of R (R Core Team). Before analyses, data cleaning and management will be conducted. Assumption testing will be conducted before and throughout the model fitting processes. Missingness will be tested, and appropriate imputation methods will be applied. Model assumptions will be evaluated, and appropriate corrections at the variable or model level will be applied so that no assumptions are violated. Potential demographic covariates (eg, age, gender) will be evaluated using a data-driven confounder selection strategy, such that only factors sharing significant variance with outcomes and predictors will be included as covariates in the final models.⁴⁰ Missingness patterns will be evaluated with the final fit,⁴¹ and the appropriate imputations will be applied (eg, multiple imputations with chained equations.⁴²

We will use mixed effects modelling and other statistical techniques to analyse the effects of open goals on physical activity over 12 months (see online supplemental file 1). This includes examining demographics, physical activity and dispositional factors influencing goal appraisal, commitment and transitions. We will also explore the motivational processes mediating these effects and identify optimal ways to prescribe open goals. Various models, such as multinomial logistic regression, Markov chain models and trajectory cluster analysis, will be employed to understand goal transitions and physical activity trajectories. Finally, we will integrate data from multiple sources to optimise the support for individuals in physical activity programmes.

Qualitative analyses

Audio recordings of interviews will be transcribed using transcription software and checked for accuracy by the lead analyst for that component of the study. Data will be extracted from the transcripts and analysed, with the researchers organising data using software such as Microsoft Word, Microsoft Excel or NVivo. Each transcript will be analysed by one researcher using template analysis⁴³ as this is a flexible method for thematically organising and analysing qualitative data. Interview transcripts will be read to aid familiarisation. Relevant segments of text to our research questions will be identified and labelled, to form descriptive and interpretive codes.⁴³ Codes will be reviewed periodically throughout the analyses, with more similar codes (ie, codes with similar meanings) clustered into more substantive subthemes. This process will then be repeated to form themes.

Trustworthiness/rigour of qualitative data and analyses

This study will use various strategies to enhance credibility, rigour and quality.⁴⁴ These include peer debriefing via regular meetings among members of the team who will act as ‘critical friends’ to stimulate critical dialogue and consider various perspectives; re-reading of transcripts to enhance familiarity with the data; prolonged engagement, which is inherent in the design of the study via multiple/repeat interviews with each participant; having different researchers analyse the data to ensure that the data are viewed from multiple/different perspectives, helping to enrich and develop more robust interpretations and reflexivity, which is considered to be an essential component of qualitative research.

Discussion

This study uses an exploratory, mixed-method, longitudinal design to describe and understand the mechanisms that explain why, when and for whom open goals are beneficial in promoting physical activity. This will be the largest study of open goals to date, and it will address key critiques, including the need for longer-term research, examination of moderating factors and understanding of transitions between open and specific goals.^{5 7} By doing so, this study will yield important insights—culminating in a programme theory—that inform the real-world implementation and scale-up of open goals for physical activity promotion.

Regarding potential limitations of this study, we note that the mobile-phone measures of participants’ step counts are not as comprehensive as other measurement approaches (eg, wrist-worn accelerometers). However, mobile phone measurement typically underestimates rather than overestimates participants’ step counts (eg, when not carried³⁹). This approach is important in terms of translational research that is easier to disseminate/implement on a large scale (ie, use of mobile phones is a more ecologically valid approach for many participants and is compatible with programmes and initiatives that will use open goals in future such as publicly available walking programmes). Another potential limitation is that we are not stratifying the sample by participants’ levels of physical activity or focusing solely on individuals who are insufficiently active. However, our recruitment methods will be aimed at individuals seeking to increase their levels of physical activity (ie, we anticipate that the majority of participants will be insufficiently active), and previous research identified that one’s level of physical activity may be an important factor in determining how acceptable open goals are.⁶ Despite these potential limitations, the project has notable strengths, including repeated measurement of step counts and self-report surveys over 12 months and the use of event-focused interviews¹⁹ to longitudinally track why, when and for whom open goals are (and are not) beneficial.

Study Status

Ethical approval was initially received in June 2024. This study was prospectively registered via the Open Science Framework (https://osf.io/gsej7/) on 18 December, 2024. The study is ongoing as of March 2025. Recruitment started in January 2025, and at the time of submission, 81 participants had commenced. We aim to conclude recruitment by August 2025 and complete data collection by August 2026, while data analysis is expected to continue through to mid-2027.

Data availability statement

No data are available. All data relevant to the study are included in the article or uploaded as supplementary information.