-->PONE-D-26-11038-->-->Using a co-design approach to develop aquatic reactive balance training for fall prevention -->-->PLOS One

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Reviewers' comments:

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-->Comments to the Author

1. Is the manuscript technically sound, and do the data support the conclusions?

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Reviewer #1: Yes

Reviewer #2: Yes

Reviewer #3: Yes

Reviewer #4: Yes

Reviewer #5: No

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-->2. Has the statistical analysis been performed appropriately and rigorously? -->

Reviewer #1: I Don't Know

Reviewer #2: N/A

Reviewer #3: N/A

Reviewer #4: Yes

Reviewer #5: I Don't Know

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Reviewer #1: Yes

Reviewer #2: Yes

Reviewer #3: No

Reviewer #4: Yes

Reviewer #5: No

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Reviewer #1: Yes

Reviewer #2: Yes

Reviewer #3: Yes

Reviewer #4: Yes

Reviewer #5: Yes

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-->5. Review Comments to the Author

Please use the space provided to explain your answers to the questions above. You may also include additional comments for the author, including concerns about dual publication, research ethics, or publication ethics. (Please upload your review as an attachment if it exceeds 20,000 characters)-->

Reviewer #1: This article explores the using of co-design approach to develop aquatic reactive balance training for fall prevention, which holds certain research value. However, the following issues still exist.

1.Among the research participants, there were only 3 elderly individuals, all of whom were female and thus not representative.

2.The key information such as the training structure, frequency, duration, action composition, and safety standards of the final solution of AquaReBal is not clearly presented, which is not conducive to replication and promotion. It is suggested to supplement the core details of the protocol.

Reviewer #2: Introduction:

- Introduction is lengthy with repetition of the main idea of the work done. Please modify.

Methods:

- I am not sure why the authors refer to participating older adults as “partners”. It might be a cultural thing, but it is confusing. Please modify to participants.

- Authors need to declare how their recruitment process went. How did they choose their older adult participants? What were their inclusion and exclusion criteria? Every detail matters.

- Authors did good preparatory steps with consultation of experts related to RBT and aquatic therapy to make an evidence-based intervention. And while the idea of co-designing the program with the recipients in mind is indeed promising. Including very few older adult participants (only 3 women) made the results reflect a mere personal opinion rather than becoming reflective of a group of older adults and limits the value of the work done. Including more older adults and analyzing their sociodemographic and functional levels or adding baseline and post-intervention functional levels of the participants could have added a greater value to this work

Results:

- Authors start the results section with a section related to how information gathering process proceeded. Any information related to the process of the design itself belongs to the methods section. The findings of each step of that process belongs to the results. Please rearrange accordingly.

- Authors should code their participants with numbers and cite that code with their quoted opinion.

- Authors mentioned using Balance Intensity Scale to measure perceived intensity in the results section. Please add any used measurement tool to the methods section as well.

Reviewer #3: The topic addressed in this manuscript is timely, clinically relevant, and aligns with current priorities in rehabilitation and fall prevention, particularly in ageing populations. The focus on aquatic-based balance training and the integration of participatory approaches are valuable and have the potential to contribute meaningfully to both clinical practice and intervention development.

Study design (Lines 83–94)

The study design is not sufficiently or explicitly stated. The authors should clearly define the study design in a single, concise sentence early in the section (e.g., “This study employed a qualitative co-design approach grounded in Participatory Action Research”). The current description combines conceptual frameworks without clearly positioning the study within a recognized methodological category.

Methodological clarity and rigor (Lines 116–151)

While the authors provide a detailed narrative of the co-design process (including participatory design sessions, internal team sessions, and practical testing), the methodological description remains incomplete and lacks sufficient clarity and rigor from a research design perspective.

First, although an initial information-gathering phase is mentioned (literature review and stakeholder meetings), this phase is not adequately described. There is no information on:

- how the literature review was conducted,

- how stakeholder meetings were structured,

- how data from this phase informed subsequent steps.

Second, the co-design process itself is presented as a sequence of activities (PDS1, ITS1, practical sessions, PDS2, ITS2), but important methodological details are missing. Specifically:

- The methods used within the participatory sessions are not clearly described (e.g., whether structured discussions, focus groups, workshops, or specific co-design techniques were used).

- The role of participants (e.g., level of decision-making power vs. advisory input) is not explicitly defined.

Third, although sessions were audio-recorded and supported by notes, there is no clear description of how the data were analyzed. It is unclear:

- whether a qualitative analysis was conducted,

- which analytic approach was used (e.g., thematic analysis, content analysis),

- how insights were translated into concrete design decisions.

Finally, the link between the stated theoretical framework (Participatory Action Research) and the actual procedures is not fully demonstrated. While iterative cycles are implied, the manuscript does not explicitly map the described steps onto PAR phases (e.g., reflection, planning, action).

Relevance and contribution (Lines 74–76; 406–410)

The manuscript clearly emphasizes the value of co-design and participatory approaches; however, the claimed contribution appears to be predominantly methodological rather than clinical. Both in the Introduction and Discussion, the study’s relevance is framed mainly in terms of advancing co-design practices, rather than demonstrating its added value for rehabilitation outcomes.

While these aspects are valuable, they are not sufficiently connected to the clinical significance of the AquaReBal intervention, particularly in terms of expected impact on fall prevention, improvements in balance or functional outcomes, and added value compared to existing rehabilitation approaches. As a result, the manuscript risks being perceived primarily as a process paper, with limited evidence of clinical innovation or advancement.

Results section

The Results section is not clearly delineated from the Methods and currently lacks sufficient reporting of actual findings. A substantial portion of the content describes procedural aspects of the co-design process, which would be more appropriately presented in the Methods section.

In contrast, the results of the co-design process itself are underdeveloped and insufficiently reported. There is limited detail on the specific suggestions made by participants, the nature of the feedback is not clearly categorized, and the concrete changes made to the intervention based on participant input are not systematically presented.

This limits the reader’s ability to understand what was learned from participants, how their contributions shaped the intervention, and the added value of the participatory approach.

Reviewer #4: Significant Clinical Contribution: This study introduces an innovative, co-designed aquatic reactive balance training protocol (Aqua ReBal) that directly addresses major barriers in traditional fall-prevention programs. Exceptional Methodological Rigor: The integration of the GRIPP2 framework guarantees a high standard of transparency and active stakeholder engagement throughout the design process. High Practical Utility: The insights generated from older adult partners offer actionable solutions that significantly enhance participant safety, comfort, and long-term adherence.

Reviewer #5: Using a co-design approach to develop aquatic reactive balance training for fall prevention

Overall Recommendation

Major Revision

This manuscript presents a timely and relevant study describing the co-design of an aquatic reactive balance training (AquaReBal) intervention for older adults. The topic is novel and clinically meaningful, particularly given the increasing interest in participatory rehabilitation research and fall prevention strategies for older adults. The integration of patient/public involvement (PPI) and aquatic therapy concepts is a notable strength.

However, the manuscript currently reads more as a descriptive project report than a rigorously structured scientific study. Several methodological, reporting, and analytical aspects require clarification and strengthening before the work is suitable for publication in PLOS ONE.

General Comments

Strengths

1. Novelty and relevance

o The concept of aquatic reactive balance training is innovative and clinically relevant for older adults with fear of falling or intolerance to land-based perturbation training.

2. Strong patient/public involvement

o The manuscript appropriately integrates older adult partners throughout the intervention development process.

o Use of the GRIPP2 framework is commendable.

3. Clear participatory workflow

o The iterative co-design process is well organized and visually represented in Figure 1.

4. Practical rehabilitation relevance

o The paper provides useful implementation insights for clinicians developing aquatic rehabilitation programs.

Major Concerns

1. Lack of rigorous qualitative methodology

The manuscript describes feedback collection through meetings, surveys, and observations, but it does not clearly describe:

• how qualitative data were analyzed,

• whether thematic analysis/content analysis/framework analysis was used,

• who coded the data,

• whether coding was inductive or deductive,

• how trustworthiness/rigor was ensured.

Currently, the Results section largely summarizes discussions narratively rather than presenting a formal qualitative analysis.

Recommendation

The authors should:

• explicitly describe the qualitative analytical approach,

• explain coding procedures,

• clarify how themes/categories were generated,

• include strategies for credibility and rigor (e.g., triangulation, reflexivity, audit trail, member checking).

Without this, the study lacks methodological transparency expected for qualitative/co-design research.

2. Sample size and representativeness are very limited

Only three older adult partners participated, all of whom were women and relatively active.

This substantially limits:

• transferability,

• diversity of perspectives,

• applicability to frailer populations,

• gender representation.

While the limitation is acknowledged, the manuscript tends to overstate broader applicability.

Recommendation

The discussion and conclusions should be more cautious regarding generalizability and implementation potential.

3. Insufficient detail regarding the final AquaReBal protocol

The paper describes the co-design process but does not adequately describe the final intervention itself.

Missing details include:

• session duration,

• frequency,

• total intervention dosage,

• perturbation intensity progression,

• therapist-to-participant ratio,

• safety monitoring procedures,

• exact perturbation methods,

• training goals.

For replication and implementation, readers need a clearer description of the finalized protocol.

Recommendation

Consider adding:

• a supplementary table outlining the finalized AquaReBal protocol,

• exercise progression principles,

• safety criteria and stopping rules.

4. Limited integration of co-design theory

Although participatory action research and co-design are discussed, the manuscript remains largely descriptive and does not critically engage with:

• co-design theory,

• power-sharing dynamics,

• participatory rehabilitation frameworks,

• challenges of stakeholder integration.

The Discussion would benefit from deeper theoretical interpretation.

Recommendation

Expand discussion regarding:

• how older adults influenced decision-making,

• whether any disagreements occurred,

• how consensus was achieved,

• lessons learned about participatory rehabilitation design.

5. Data availability statement inconsistency

There is a discrepancy between the submission metadata and manuscript text.

The submission form states:

“All relevant data are within the manuscript and its Supporting Information files.”

However, the manuscript states:

“The data that support the findings of this study are available from the corresponding author upon reasonable request.”

PLOS ONE requires consistency and generally discourages “available on request” statements unless justified.

Recommendation

Revise the data availability statement to comply fully with PLOS ONE policy.

Minor Concerns

1. Language and grammar issues

Several sentences require proofreading.

Examples:

• “to to shape the program”

• “water environment” should often be “aquatic environment”

• inconsistent use of “partners,” “participants,” and “older adults”

A professional language edit is recommended.

2. Figures need improvement

Some figures appear visually low-resolution and difficult to interpret:

• Figure 3

• Figure 4

The Miro/Freeform screenshots look informal for journal publication.

Recommendation

Convert figures into professionally formatted thematic diagrams/tables.

3. Limited demographic reporting

The manuscript provides minimal participant characteristics.

Recommendation

Include:

• age range,

• ethnicity,

• mobility status,

• assistive device use,

• fall history,

• aquatic confidence/swimming ability.

4. Reflexivity statement missing

Given the participatory nature of the study, the manuscript should discuss:

• researchers’ positionality,

• prior relationships with participants,

• potential influence on data interpretation.

5. Need clearer distinction between feasibility and intervention efficacy

At times, the manuscript implies therapeutic benefit despite no outcome evaluation.

Recommendation

Avoid efficacy-oriented language unless formally tested.

For example:

• “demonstrating potential for broader implementation”

may overstate findings.

Section-Specific Comments

Abstract

The abstract is clear overall but should mention:

• the qualitative/co-design analytical approach,

• the small sample size as context.

Introduction

Strong rationale overall. However:

• the distinction between aquatic therapy and aquatic reactive balance training should be more explicitly defined,

• stronger mechanistic rationale for why aquatic perturbation training may improve reactive balance would strengthen the paper.

Methods

This section requires the most improvement.

Please clarify:

• recruitment strategy,

• inclusion/exclusion criteria,

• qualitative analysis procedures,

• survey questions/scales,

• documentation methods,

• decision-making process for incorporating feedback.

Results

The Results section currently mixes:

• descriptive reporting,

• interpretation,

• participant quotes.

Consider reorganizing into themes/subthemes.

A thematic table summarizing:

• barriers,

• facilitators,

• design recommendations,

would substantially improve readability.

Discussion

The Discussion is generally appropriate but should:

• critically discuss limitations of participatory co-design,

• better integrate qualitative methodology literature,

• avoid overclaiming intervention readiness.

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Reviewer #1: No

Reviewer #2: No

Reviewer #3: No

Reviewer #4: No

Reviewer #5: No

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Submitted filename: PONE-D-26-11038.docx

Using a co-design approach to develop aquatic reactive balance training for fall prevention

PONE-D-26-11038R1

Dear Dr. Carusone,

We’re pleased to inform you that your manuscript has been judged scientifically suitable for publication and will be formally accepted for publication once it meets all outstanding technical requirements.

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Kind regards,

Renato S. Melo, PhD

Academic Editor

PLOS One

Additional Editor Comments (optional):

Reviewers' comments:

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-->Comments to the Author

1. If the authors have adequately addressed your comments raised in a previous round of review and you feel that this manuscript is now acceptable for publication, you may indicate that here to bypass the “Comments to the Author” section, enter your conflict of interest statement in the “Confidential to Editor” section, and submit your "Accept" recommendation.-->

Reviewer #1: All comments have been addressed

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-->2. Is the manuscript technically sound, and do the data support the conclusions?

The manuscript must describe a technically sound piece of scientific research with data that supports the conclusions. Experiments must have been conducted rigorously, with appropriate controls, replication, and sample sizes. The conclusions must be drawn appropriately based on the data presented. -->

Reviewer #1: Partly

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-->3. Has the statistical analysis been performed appropriately and rigorously? -->

Reviewer #1: Yes

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-->4. Have the authors made all data underlying the findings in their manuscript fully available?

The PLOS Data policy requires authors to make all data underlying the findings described in their manuscript fully available without restriction, with rare exception (please refer to the Data Availability Statement in the manuscript PDF file). The data should be provided as part of the manuscript or its supporting information, or deposited to a public repository. For example, in addition to summary statistics, the data points behind means, medians and variance measures should be available. If there are restrictions on publicly sharing data—e.g. participant privacy or use of data from a third party—those must be specified.-->

Reviewer #1: Yes

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-->5. Is the manuscript presented in an intelligible fashion and written in standard English?

PLOS ONE does not copyedit accepted manuscripts, so the language in submitted articles must be clear, correct, and unambiguous. Any typographical or grammatical errors should be corrected at revision, so please note any specific errors here.-->

Reviewer #1: Yes

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-->6. Review Comments to the Author

Please use the space provided to explain your answers to the questions above. You may also include additional comments for the author, including concerns about dual publication, research ethics, or publication ethics. (Please upload your review as an attachment if it exceeds 20,000 characters)-->

Reviewer #1: The authors did a lot of work on this study. The revised manuscript has been substantial improvement. Thank you�

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Reviewer #1: No

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