-->PONE-D-25-17971-->-->Fast-and-frugal trees: A decision tool for elite sports-->-->PLOS ONE

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Academic Editor

PLOS ONE

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3. Thank you for stating the following financial disclosure: [This work was supported by the Bundesinstitut für Sportwissenschaft (German Federal Institute for Sport Sciences) in 2021–2025 under Grant No. 081901/21-25 (English title: Individual performance development in elite sports by holistic and transdisciplinary process optimization). The data analyzed for the purposes of this study were part of a multidisciplinary large-scale data set that included multiple points of measurement and a cross-sectional and longitudinal perspective. The subset of data included in this study covered the cross-sectional data collected in the period 01/2022–12/2023.].  

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5. We are unable to open your Supporting Information file S4.1 trampoline.eps and S4.2 volleyball.eps. Please kindly revise as necessary and re-upload.

Additional Editor Comments:

Dear Authors,

Please revise the manuscript considering the reviewers´ suggestions.

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Reviewers' comments:

Reviewer's Responses to Questions

-->Comments to the Author

1. 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: Yes

Reviewer #2: Yes

Reviewer #3: Yes

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

Reviewer #1: Yes

Reviewer #2: Yes

Reviewer #3: Yes

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-->3. 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

Reviewer #2: Yes

Reviewer #3: Yes

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-->4. Is the manuscript presented in an intelligible fashion and written in standard English?

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Reviewer #1: Yes

Reviewer #2: Yes

Reviewer #3: 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: The use of Fast-and-Frugal Trees (FFTs) in sports performance forecasting represents an interesting methodological advance that addresses the need for rapid, transparent, and efficient decision-making in contexts where time and clarity are critical, such as sports. Unlike complex statistical models or deep learning algorithms, FFTs offer a simplified decision structure that prioritizes speed and straightforward interpretation, which is especially valuable for coaches.

One of the study's key strengths is its ability to balance accuracy and usability. FFTs are easily understandable and applicable in real-world settings without requiring advanced software, which favors their implementation in sports clubs, youth national teams, and development programs. Furthermore, their explicit, hierarchical design facilitates communication between analysts and coaching staff.

However, it is important to recognize certain limitations inherent to the model. While FFTs perform well in binary decision settings or when speed is prioritized over complexity, they may have lower predictive capacity than more robust models (such as Random Forests or neural networks) in contexts with nonlinear data or many interactions between variables. Furthermore, their performance can be sensitive to the initial feature selection, which requires methodological care in the design stage.

This study constitutes a valuable contribution to the field of sports performance by demonstrating that it is possible to build agile and accessible predictive models without sacrificing their practical utility. The use of FFTs invites us to rethink how informed decisions are made in everyday sports contexts, highlighting that heuristic simplicity can be a virtue in complex environments, provided it is supported by rigorous empirical evidence.

Reviewer #2: Title of Manuscript: Fast-and-frugal trees: A decision tool for elite sports

Manuscript ID: PONE-D-25-17971

Reviewer’s report

First, I would like to warmly acknowledge the considerable effort behind this manuscript. The multidisciplinary approach, the ambition to simplify complex decision-making through FFTrees, and the relevance to elite sports settings are evident throughout the work. My comments aim to support the authors in refining the manuscript to meet the high scientific and editorial standards required by PLOS ONE. I have structured the feedback section by section, with explicit suggestions that I hope will be helpful in moving the paper forward.

1. Abstract

Suggestion: The structure could be improved for clarity. Consider explicitly segmenting the abstract into: Objective, Methods, Results, Conclusion.

For example:

Line 6–7: You may consider beginning with a clear objective such as: “The objective of this study was to examine the applicability of fast-and-frugal trees (FFTrees) to inform training interventions in elite athletes.”

Clarity of FFTrees: As this might be unfamiliar to some readers, consider briefly defining what FFTrees are in one sentence near the start.

2. Introduction

Objective not clearly stated:

Lines 101-104: The objective appears but is somewhat embedded. You may consider adding a clear and concise sentence like:

“The aim of this study is to develop and evaluate the predictive performance of sport-specific FFTrees to inform personalised training interventions in elite athletes.”

Theory clarification:

Lines 31-40: You refer to theoretical models but do not fully explain how these support the rationale for FFTrees. Consider integrating the constructivist or biopsychosocial lens more explicitly to frame why FFTrees are an appropriate tool for this context.

Suggestion for structure: You might consider adding subheadings or clearly defined paragraphs separating:

� Context and problem (elite sports complexity)

� Existing gaps in intervention selection

� Introduction to FFTrees as a methodological response

3. Methods

Cue Selection Explanation:

Lines 210-225: The PCA is well described but consider clarifying why each variable was selected as a cue. For example, in line 299-301, you could briefly mention the rationale for replacing information-processing speed with visual selective attention in trampoline.

Clarify Dichotomisation Criteria:

Lines 234-245: Please make the thresholding process more transparent. For instance:

� How was the “75th percentile” decided?

� Were sex and age considered in the dichotomisation?

Reproducibility:

Lines 272-273: You may consider adding the R script or relevant code as supplementary material or sharing a GitHub link, in line with open science practices.

4. Results

Table 3.1 (line 293): It would be helpful to add a brief sentence interpreting the practical relevance of each component, what does “motor cost” imply, for instance?

Figures 3.1 and 3.2:

The decision rules could be better explained in-text. For example, in line 327-328, you might add:

� “This threshold suggests that athletes with grip strength z-scores > -0.12 are classified as needing intervention, reflecting possible strength deficiencies.”

Missing data handling:

Line 256-258: Please state how many cases were excluded due to missing data, or clarify if imputation was considered.

5. Discussion

Theoretical anchoring:

Lines 382-390: While you reference the multidisciplinary and heuristic value of FFTrees, it would strengthen the paper to briefly connect to models such as constructivist decision-making or ecological dynamics, especially since you touch on bounded rationality. This would deepen the theoretical contribution.

Practical implications:

Lines 445-455: Consider adding an example of how a coach could use a FFTree in a training context. For example:

“A coach reviewing FFTree output could prioritise strength-based interventions if the tree identifies grip strength or CMJ as first-level cues.”

Limitations:

While limitations are mentioned (Lines 491-494), it would benefit from a clearer subsection or paragraph that includes:

� Small sample sizes for team sports

� Model instability across random partitions

� Generalisation limitations to youth or non-German athletes

6. Conclusion

Line 511 onward: The conclusion is strong but consider softening claims slightly to reflect the proof-of-concept nature of the study. For example:

“These preliminary findings suggest that FFTrees may offer a practical, transparent method for guiding individualised training decisions, though further research with larger samples is recommended.”

7. Language and style

Orthographic errors:

Line 101: “and whether they can be validated…” is incomplete or has a clause error.

Line 249, 304, and several others: Consider reviewing sentence punctuation. Several sentences are long and lack commas, which makes them harder to follow, this may stem from AI-assisted generation.

Recommendation: A thorough proofreading by a native English speaker or professional editor would improve clarity and flow and meet the PLOS ONE criterion for “standard English.”

Final recommendation: major revision

This is a promising and well-structured study with a novel approach, but it would benefit from clearer articulation of objectives, tighter theoretical framing, enhanced methodological transparency, and improvements to writing and formatting.

I encourage the authors to consider the suggestions outlined above, not as criticisms, but as constructive steps toward strengthening their valuable contribution to performance science.

Reviewer #3: Thank you for submitting the manuscript to Plus One.

The topic of the study is highly valuable and, more importantly, practical and experience-based. The authors’ effort to contribute to the enhancement of elite athlete performance by applying evidence-based sport science principles is both commendable and timely.

The significance of the study's outcomes is further reinforced by the choice of participants—German national team athletes—who represent one of the leading nations in both individual and team-based sports at the international level.

I congratulate the research team on their efforts. However, I believe that the following points—if addressed—can substantially improve the quality and impact of the manuscript:

1. The title is somewhat generic. Given the strong applied dimension of this study, I suggest emphasizing the performance enhancement aspect in the title to increase its attractiveness and specificity.

2. Please consider rewriting the final lines of the abstract to emphasize the contribution to performance science and coaching practice more clearly.

3. Although the methodological approach is sound, the sample sizes (n = 27 for trampoline, n = 53 for volleyball) are relatively small. This particularly limits generalizability for the trampoline model and should be addressed more explicitly in the limitations section.

4. What specific challenges did the research team face while athletes completed questionnaires or diagnostic tests, given the constraints of elite training environments? Clarifying this in the discussion or limitations section may be insightful.

5. Clearly identify the cognitive cues used for each sport to help readers better understand the sport-specific adaptations of the FFTrees.

6. Consider simplifying or contextualizing the key outputs (e.g., cut-off values, cue combinations) in a way that is easier for coaches at various levels to interpret and apply.

7. It would enhance the practical relevance of the study to provide concrete, real-world examples of how each cue can be implemented in athlete monitoring or decision-making.

8. Several sentences in the discussion are long and dense. Revising into shorter, clearer statements would improve readability.

9. Please elaborate more on the difference in FFTree performance between individual (trampoline) and team sports (volleyball). This is an important insight for readers.

10. Correct the term "instable FFTrees" to "unstable FFTrees" for better clarity and technical accuracy.

11. If possible, discuss the transferability of this approach to other sports or organizational settings to broaden its application.

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Reviewer #1: No

Reviewer #2: No

Reviewer #3: Yes:  Dr Mahdi Gharibzadeh

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Attachments

Attachment

Submitted filename: 17971_FFT.pdf

How fast-and-frugal trees can inform diagnostic and intervention decisions for enhancing elite athlete performance

PONE-D-25-17971R1

Dear Dr. Lena Siebert,

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.

Within one week, you’ll receive an e-mail detailing the required amendments. When these have been addressed, you’ll receive a formal acceptance letter and your manuscript will be scheduled for publication.

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Mário Espada, PhD

Academic Editor

PLOS ONE

Reviewers' comments:

Reviewer's Responses to Questions

-->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 #2: All comments have been addressed

Reviewer #3: 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 #2: Yes

Reviewer #3: Yes

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

Reviewer #2: Yes

Reviewer #3: 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 #2: Yes

Reviewer #3: 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 #2: Yes

Reviewer #3: 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 #2: The manuscript is well-conceived, methodologically sound, and clearly written. The objectives, procedures, and conclusions are coherent and contribute meaningfully to the field. No ethical concerns were identified. I am satisfied with the overall quality of the work and recommend it for publication with no major changes.

Reviewer #3: The revisions made to the manuscript have been reviewed and are deemed acceptable. However, it is important to note that all comments provided by the reviewers must be thoroughly addressed in the authors’ response letter. The responses should specifically refer to each comment with detailed explanations. In this case, the responses were presented in a general manner and lacked the necessary completeness.

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