Biomechanical and Physiological Comparison Between a Conventional Cyclist and a Paralympic Cyclist with an Optimized Transtibial Prosthesis Design

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

Aim and scope

This study had two main goals:

1. Comparison of Performance: Evaluate and compare the physiological and biomechanical performance of a Paralympic cyclist using bilateral transtibial prostheses with that of a conventional (able-bodied) cyclist during a progressive cycling test.
2. Prosthesis Development: Describe the engineering process behind designing the prosthesis (Design 1.4) using Quality Function Deployment, CAD, Finite Element Analysis, Computational Fluid Dynamics, and topological optimization.

The research addresses a gap in literature by analyzing functional adaptations of elite Paralympic athletes under standardized conditions.

Methodology overview

Design:

Comparative case study with n=2 participants - one Paralympic cyclist with bilateral transtibial amputations and a conventional cyclist - matched for performance levels.

Procedures:

• Incremental cycling test starting at 100W with 50W increases every 3 minutes until exhaustion.
• Physiological measures:
• VO_2max (maximal oxygen uptake)
• Respiratory Exchange Ratio (RER)
• Anaerobic threshold
• Lactate levels
• Heart rate
• Biomechanical measures:
• 3D motion capture of trunk, hip, knee, and ankle kinematics.

Prosthesis development:

• Multiple simulations validated structural integrity, resonance behavior, and aerodynamic efficiency.
• Modal analysis showed natural frequencies outside the cadence range (90–120 rpm), reducing risk of resonance.

Key results

Physiological findings

• Maximal Workload: both cyclists reached 350W.
• VO₂max:
• Conventional: 4.26 L/min (69 ml/kg/min)
• Paralympic: 3.53 L/min (52 ml/kg/min, 120% of predicted)
• Anaerobic threshold:
• Conventional: 3.22 L/min (52 ml/kg/min)
• Paralympic: 2.57 L/min (38 ml/kg/min)
• Lactate threshold:
• Almost identical (8.1 vs. 8.0 mmol)
• RER at peak:
• Paralympic cyclist higher (1.32 vs. 1.11), indicating greater anaerobic contribution.
• Heart rate:
• Both exceeded 110% of predicted maximums.

Interpretation:

Although the Paralympic athlete had lower absolute aerobic capacity, he demonstrated:

• Exceptional relative efficiency
• High anaerobic tolerance
• Capacity to sustain submaximal exertion comparably.

Biomechanical findings

The Paralympic cyclist showed:

• Greater joint ranges of motion in hip, knee, and ankle.
• Lower trunk angular variability, indicating effective postural control.
• Greater asymmetries (e.g., in hip ROM), interpreted as compensatory strategies.

Figures of note (from pages 10–13):

• Figure 5 - 8 illustrate detailed kinematic curves:
• Trunk movement: Paralympic cyclist had higher ROM (2.4°) with lower variability.
• Hip and knee: Greater ROM in Paralympic cyclist, but more asymmetry.
• Ankle: Larger ROM with less variability compared to the conventional cyclist.

These adaptations likely reflect neuromuscular strategies to maintain efficient pedaling without ankle plantar flexion.

Strengths

Comprehensive Evaluation: combines engineering design, physiology, and biomechanics.

Advanced Methods: rigorous simulation and testing protocols.

Relevance: addresses performance optimization in adaptive sports.

Transparency: Clear acknowledgment of limitations and thorough methodological description.

Limitations

Sample size: n=2 limits statistical inference - results are exploratory.

Generalizability: findings may not apply to all Paralympic cyclists.

Equipment Dependence: specialized equipment may not be universally accessible.

Conclusions

This study convincingly demonstrates that:

• Optimized prosthetic design can help close performance gaps between Paralympic and able-bodied athletes.
• Paralympic athletes can achieve high-level performance through tailored engineering and training.

The authors recommend further research with larger cohorts to validate and expand these insights.

Reviewer perspective

This paper is well-organized and scientifically rigorous within the constraints of a case study. It successfully integrates engineering innovation and sports physiology to illustrate the potential of adaptive technology. The findings support the transformative impact of user-centered prosthesis design on competitive performance.

Recommendation:

Acceptable for publication with minor clarifications: e.g. discussing potential confounding variables like training history and muscle composition.

Comments for author File: Comments.pdf

Author Response

Reviewer 1.

Comment 1: Does the introduction provide sufficient context and include all relevant references? Is the research design appropriate? Are the methods adequately described? Are the results clearly presented? Are the conclusions supported by the results? Are all figures and tables clear and well-presented?
Response 1: Thank you for pointing this out. We agree with this comment. Therefore, we have revised and clarified all these evaluation criteria in the revised manuscript. The introduction was expanded to include more context and references, the research design was explained in greater detail, the methods section was written more explicitly, the results were reformatted for greater clarity, the conclusions now explicitly state their relationship with the results, and the figure and table captions were revised to be self-contained, including units and explanations of colors and symbols. All these general improvements are highlighted in yellow in the revised manuscript for all three reviewers, who rated this item as “Can be improved.”

Comment 2: Discuss potential confounding variables such as training history and muscle composition. These are adjusted in blue.
Response 2: Potential confounding variables, such as training history and muscle composition, have been included. These are adjusted on page 14, last paragraph, lines 528–543, which is marked in red in the manuscript.
Updated text in the manuscript: It is important to emphasize that the findings of this study should be interpreted within the inherent limitations of its comparative case design. While the physiological and biomechanical profiles of the Paralympic and conventional cyclists provide valuable insights into functional adaptations and the potential of optimized prosthetic design, including only one athlete per category does not allow for broad generalizations about these populations. Rather, this study is presented as an exploratory analysis and a methodological validation of the measurement protocols and simulation frameworks employed, which is consistent with the use of single-subject designs in sports medicine for highly specialized populations (Thomas et al., 2012). Both participants were confirmed as professional cyclists, belonging to the national and international Olympic and Paralympic systems, which ensures a high-performance level and competitive relevance of the observed data. Nevertheless, the limited sample size precludes inferential analysis and requires cautious interpretation of these results when extrapolating to other athletes. Future studies are recommended to recruit larger and more homogeneous cohorts to confirm these findings and better isolate the effects of prosthetic design, training history, and individual variability on performance outcomes.

Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and Suggestions for Authors

I appreciate the authors' comparative analysis and the rigor of the employed methods; however, I believe the manuscript contains several ambiguities and could be significantly improved. I encourage the authors to address the following essential aspects:

It is not methodologically sound to draw general conclusions based on a single data pair (able-bodied + para-athlete). Such data may be used to validate measurement protocols or simulation frameworks, but not to support broader claims about the domain. The limitations imposed by this setup must be explicitly acknowledged and discussed. Relying on a single subject is insufficient even for the para-athlete category—let alone for able-bodied athletes. Furthermore, it is unclear whether the participants are professional cyclists or amateurs.

The manuscript does not clarify whether the prosthesis was designed by the authors or provided by the para-athlete. Key technical details regarding the prosthesis are missing: is it custom-built specifically for cycling? Which joints are omitted or rigid? How does its kinematic and dynamic performance compare to a human limb? In the context of expanding the test group, a comparative analysis of different prosthetic types might be valuable. Additionally, the text refers to a “Design 1.4” without clearly indicating its context or relevance—this point must be clarified.

Based on the comparative performance analysis, the authors should propose directions for future development or optimization of the prosthesis.

Author Response

Reviewer 2.

Comment 1: Does the introduction provide sufficient context and include all relevant references? Is the research design appropriate? Are the methods adequately described? Are the results clearly presented? Are the conclusions supported by the results? Are all figures and tables clear and well-presented?
Response 1: Thank you for pointing this out. We agree with this comment. Therefore, we have revised and clarified all these evaluation criteria in the revised manuscript. The introduction was expanded to include more context and references, the research design was explained in greater detail, the methods section was written more explicitly, the results were reformatted for better clarity, the conclusions now explicitly indicate their relationship with the results, and the figure and table captions were revised to be self-contained, including units and explanations of colors and symbols. All these general improvements are highlighted in yellow in the revised manuscript for the three reviewers, who rated this item as “Can be improved.”

Comment 2: It is not methodologically sound to draw general conclusions based on a single pair of data (able-bodied athlete + para-athlete). Such data can be used to validate measurement protocols or simulation frameworks but not to support broader claims about the domain. The limitations imposed by this setup must be explicitly acknowledged and discussed. Basing conclusions on a single subject is insufficient even for the para-athlete category, let alone for able-bodied athletes. Furthermore, it is not clear whether the participants are professional or amateur cyclists.
Response 2: This adjustment was made on page 14, last paragraph, lines 528–543, which is marked in red in the manuscript.
Updated text in the manuscript: It is important to emphasize that the findings of this study should be interpreted within the inherent limitations of its comparative case design. While the physiological and biomechanical profiles of the Paralympic and conventional cyclists provide valuable in-sights into functional adaptations and the potential of optimized prosthetic design, in-cluding only one athlete per category does not allow for broad generalizations about these populations. Rather, this study is presented as an exploratory analysis and a methodo-logical validation of the measurement protocols and simulation frameworks employed, which is consistent with the use of single-subject designs in sports medicine for highly specialized populations (Thomas et al., 2012). Both participants were confirmed as profes-sional cyclists, belonging to the national and international Olympic and Paralympic sys-tems, which ensures a high-performance level and competitive relevance of the observed data. Nevertheless, the limited sample size precludes inferential analysis and requires cautious interpretation of these results when extrapolating to other athletes. Future studies are recommended to recruit larger and more homogeneous cohorts to confirm these find-ings and better isolate the effects of prosthetic design, training history, and individual variability on performance outcomes.

Comment 3: The manuscript does not clarify whether the prosthesis was designed by the authors or provided by the para-athlete. Key technical details about the prosthesis are missing: is it custom-made for cycling? Which joints are omitted or rigid? How does its kinematic and dynamic performance compare to a human limb? In the context of expanding the test group, a comparative analysis of different prosthetic types could be valuable. In addition, the text refers to “Design 1.4” without clearly indicating its context or relevance; this point should be clarified.
Response 3: This adjustment was made on page 2, last paragraph, lines 81–121, which is marked in red in the manuscript.
Updated text in the manuscript: The transtibial prosthesis employed by the Paralympic cyclist (Design 1.4) was de-veloped through a user-centered engineering framework. Quality Function Deployment (QFD) was first used to establish functional modules and design requirements (Akao, 1990). Three conceptual sockets were digitally modeled using Computer-Aided Design (CAD) software. These were structurally assessed using Finite Element Analysis (FEA) in ANSYS Workbench®, evaluating mechanical performance under simulated pedaling forces, including stress distribution, buckling, fatigue resistance, and drop-impact re-sponse (Cook et al., 2002). Simultaneously, Computational Fluid Dynamics (CFD) simula-tions were performed to examine aerodynamic behavior. Topological optimization was implemented to reduce structural mass without compromising stiffness (Bendsøe & Sig-mund, 2003). Design 1.4 exhibited optimal stress dissipation, aerodynamic efficiency, and anatomical conformity. Modal analysis confirmed its natural frequencies were outside the typical pedaling cadence range (90–120 rpm), minimizing resonance risk. Drop-impact simulations indicated deformations under 1.6 mm, validating the prosthesis's energy ab-sorption capacity and impact tolerance. No generative artificial intelligence (GenAI) tools were used in data generation, study design, or analysis. Only minor language editing support (grammar and formatting) was provided using ChatGPT-4 for linguistic clarity.

The prosthesis was entirely designed, developed, and optimized by the research team, specifically tailored to the characteristics of the Paralympic cyclist who participated in the experiments. The design process followed a structured engineering approach, consisting of four main stages: conceptual design, preliminary design, detailed design, and CAD modeling. In the conceptual stage, the user’s needs were identified, the scope of the re-search was defined, the product architecture was outlined, and initial sketches were cre-ated along with statistical analyses. In the preliminary design phase, a review of the state of the art on aerodynamic profiles and materials was conducted, the everyday training scenario of the Paralympic cyclist was defined, 3D scans of the endo-socket were per-formed, and the socket geometry was established. The detailed design stage included analyses of the cyclist’s kinematic behavior during training, as well as evaluation of me-chanical parameters of the crank link, crank rotation angle, force distribution, kinematic modeling of the cyclist, and dynamic modeling of the transtibial prosthesis.

Following these stages, four CAD versions (1.1, 1.2, 1.3, and 1.4) were developed and evaluated using FEA. The evaluations included static, frequency, topology, buckling, fa-tigue, drop, and aerodynamic performance analyses. Among all prototypes, CAD 1.4 demonstrated superior mechanical, aerodynamic, and anatomical performance and was therefore selected as the final optimized design. The prostheses were designed to be rigid at the ankle joint, as the athlete presented with bilateral transtibial amputations, function-ally preserving the hip and knee joints, while replacing the ankle-foot complex. This con-figuration made it possible to assess the kinematic and dynamic behavior of the prostheses compared to the equivalent joints of a conventional cyclist, with the aim of determining to what extent the prosthetic limbs could approximate the biomechanics and physiology of human extremities.

Comment 4: The limitations imposed by this setup must be explicitly acknowledged and discussed.
Response 4: This adjustment was made on page 15, paragraph 3, lines 562–572, which is marked in red in the manuscript.
Updated text in the manuscript: When comparing the different versions, CAD 1.4 showed significant advantages that justified its selection as the final solution. This design demonstrated greater structural strength in static and fatigue analyses, as well as better stress distribution, ensuring in-creased durability and safety under repetitive loads. Topological optimization allowed for weight reduction without sacrificing stiffness or stability, thereby improving the cyclist’s efficiency. Additionally, it offered superior aerodynamic performance, with reduced air re-sistance and lower deformations in impact and buckling tests, contributing to more stable and safer performance. It also achieved a more precise anatomical fit to the cyclist’s stump, enhancing comfort, reducing pressure points, and providing greater dynamic stability by keeping its natural frequencies outside the pedaling cadence range, thereby avoiding un-wanted resonances.

However, these advantages were accompanied by some drawbacks. The high level of specialization and detail in CAD 1.4 increased manufacturing complexity and costs, due to the need for more advanced production processes. Furthermore, being highly custom-ized to the characteristics of the evaluated cyclist, its versatility for adaptation to other us-ers without additional modifications is limited. These considerations were carefully weighed and, despite its limitations, CAD 1.4 was validated as the most effective and suitable solution for the purposes of this study.

Comment 5: Based on the comparative performance analysis, the authors should propose directions for future development or optimization of the prosthesis.
Response 5: This adjustment was made on page 15, paragraph 2, lines 549–572, which is marked in red in the manuscript.

Updated text in the manuscript: Based on the comparative performance analysis, future developments of the transtib-ial prosthesis could focus on further reducing its weight and improving energy transfer efficiency, while maintaining structural integrity and stability. The incorporation of ad-vanced lightweight composite materials, as well as the optimization of internal geometry to minimize unnecessary mass, could help reduce the metabolic cost of pedaling. Addi-tionally, exploring semi-active or adaptive components, such as adjustable stiffness mod-ules at the socket or footplate interface, could enhance comfort and dynamic responsive-ness under different cycling conditions. Refining the aerodynamics of the prosthetic shape, especially for road cycling with high physical demands as reflected in the anthro-pometric and physiological profiles of the Paralympic cyclist, also represents a promising direction. Finally, testing and validating these improvements in larger cohorts of Paralym-pic athletes would contribute to a stronger evidence base to guide future prosthetic design optimizations.

Author Response File: Author Response.pdf

Reviewer 3 Report

Comments and Suggestions for Authors

Dear Authors,

Thank you for submitting your manuscript titled "Biomechanical and Physiological Comparison Between a Conventional Cyclist and a Paralympic Cyclist with an Optimized Transtibial Prosthesis Design." The study presents a novel and compelling interdisciplinary approach, combining advanced prosthetic design with physiological and biomechanical performance assessment. Your work contributes meaningfully to the fields of adaptive sports and prosthetic engineering.

I commend the thoroughness of the design and data collection processes, and the integration of engineering and clinical methodologies. Below, I offer several suggestions aimed at improving clarity, depth, and potential impact:

Major Recommendations

1. Clarify Study Scope and Generalizability
   While your focus on a case-comparison between a Paralympic and conventional cyclist is appropriate and valuable, please elaborate more explicitly in the Discussion and Limitations sections on the scope and generalizability of the findings. Readers unfamiliar with case-study methodologies may otherwise misinterpret the results as broadly generalizable.

2. Enhance Contextual Framing in the Discussion
   The Discussion could benefit from a slightly broader contextualization:

   • How do your findings compare with existing literature on elite-level para-cycling performance?

   • Can the principles used in the prosthesis design (e.g., FEA, CFD, topology optimization) be generalized to other types of sports prostheses?

   • What practical insights might coaches, physiotherapists, or engineers draw from your study?

3. Explain Clinical or Functional Relevance of Kinematic Findings
   While the kinematic analysis is rich, consider adding a brief interpretation of how observed differences (e.g., in ROM or trunk variability) may affect long-term performance, fatigue, or injury risk. This would strengthen the practical value of the analysis.

4. Prosthesis Validation and Patent Status
   Since the prosthesis (Design 1.4) is central to the study:

   • Have clinical validations or extended field tests been conducted beyond this case?

   • Is the design undergoing regulatory or patent filing processes?

   • Adding a brief note on this would enhance the translational impact of your study.

Regards

Comments on the Quality of English Language

Figures & Tables:

Please ensure that figure captions are self-contained and sufficiently descriptive.

Consider improving the visual contrast and legibility of line graphs (Figures 5–8), especially where multiple curves overlap.

Terminology Consistency:

Use consistent terminology throughout the manuscript (e.g., VO₂max vs. Vo₂max, RER vs. respiratory exchange ratio).

Ensure that all acronyms are defined at first mention (you’ve done this well in most cases).

Grammar and Style:
The language is clear overall. However, a final round of minor language editing (especially in the abstract and conclusions) would improve fluency.

Author Response

Reviewer 3.

Comment 1: Does the introduction provide sufficient context and include all relevant references? Is the research design appropriate? Are the methods adequately described? Are the results clearly presented? Are the conclusions supported by the results? Are all figures and tables clear and well-presented?
Response 1: Thank you for pointing this out. We agree with this comment. Therefore, we have revised and clarified all these evaluation criteria in the revised manuscript. The introduction was expanded to include more context and references, the research design was explained in greater detail, the methods section was written more explicitly, the results were reformatted for greater clarity, the conclusions now explicitly indicate their relationship with the results, and the figure and table captions were revised to be self-contained, including units and explanations of colors and symbols. All these general improvements are highlighted in yellow in the revised manuscript for the three reviewers, who rated this item as “Can be improved.”

Comment 2: Clarify the scope and generalizability of the study. While your focus on a case comparison between a Paralympic and a conventional cyclist is appropriate and valuable, please explain in more detail the scope and generalization of the findings in the "Discussion" and "Limitations" sections. Readers unfamiliar with case study methodologies might misinterpret the results as broadly generalizable.
Response 2: This adjustment was made in the Discussion (page 15, paragraph 4, lines 573–581), which is marked in blue in the manuscript, and in the Conclusion (page 16, paragraph 3, lines 625–629), also marked in blue in the manuscript.
Updated text in the manuscript: In discussión, It is important to note that the findings of this study should not be interpreted as broadly generalizable. The comparative case study design allowed for an in-depth char-acterization of two elite cyclists with unique physiological and biomechanical profiles under controlled conditions, which is valuable for hypothesis generation and methodo-logical validation. However, due to the inclusion of only one Paralympic and one conven-tional athlete, the results are specific to these individuals and serve primarily to illustrate potential functional adaptations and inform future research directions. Further studies with larger, more representative samples are needed to confirm the observed trends and strengthen the evidence base.

In Conclusions: Given the small sample size, these findings should be interpreted with caution, as they are exploratory and specific to the athletes studied. Nevertheless, the study provides valuable insights and a methodological framework for future research on adaptive cycling performance and prosthetic optimization, highlighting the importance of refining pros-thetic designs to further reduce energy cost and improve biomechanical efficiency.

Comment 3: Improve the contextual framework in the Discussion. The discussion could benefit from a slightly broader context: How do your findings compare with existing literature on elite-level Paralympic cycling performance? Can the principles used in prosthetic design (e.g., FEA, CFD, topological optimization) be generalized to other types of sports prostheses? What practical insights could coaches, physiotherapists, or engineers take from your study?
Response 3: This adjustment was made (page 13, paragraph 4, lines 465–482), marked in blue in the manuscript.
Updated text in the manuscript: 

The findings of this study align with prior research indicating that elite-level Paralympic cyclists can achieve competitive performance through remarkable physiological adaptations and biomechanically efficient movement strategies, despite inherent mechanical constraints (Frossard, 2012; Lechler et al., 2018). The observation of high relative VO₂max, efficient lactate tolerance, and stable kinematic patterns in the Paralympic cyclist is consistent with literature reporting that targeted training and tailored prosthetic design enable para-athletes to narrow the performance gap with able-bodied peers. Moreover, the engineering principles applied in this study—Finite Element Analysis (FEA), Computational Fluid Dynamics (CFD), and topological optimization—are not limited to transtibial cycling prostheses and could be generalized to the design of other sport-specific prosthetic devices, such as running blades or upper-limb prostheses for adaptive rowing or climbing, by optimizing mechanical, aerodynamic, and anatomical factors.

From a practical perspective, the study provides valuable insights for coaches, physiotherapists, and engineers: it highlights the importance of integrating biomechanical assessment, individualized training regimens, and advanced engineering techniques to maximize performance and minimize injury risk in adaptive sports. This multidisciplinary approach can inform the development of evidence-based protocols for athlete preparation and prosthetic innovation.

Comment 4: Explain the clinical or functional relevance of the kinematic findings. While the kinematic analysis is comprehensive, please consider adding a brief interpretation of how the observed differences (e.g., in ROM or trunk variability) might affect long-term performance, fatigue, or injury risk. This would strengthen the practical value of the analysis.
Response 4: This adjustment was made (page 14, paragraph 2, lines 498–509), marked in blue in the manuscript.
Updated text in the manuscript: 

The observed kinematic differences, such as the increased joint range of motion (ROM) and reduced trunk variability in the Paralympic cyclist, have relevant functional and clinical implications. Greater ROM at the hip, knee, and ankle may reflect adaptive strategies to compensate for the lack of ankle musculature, enabling efficient power transfer despite prosthetic constraints. However, this increased mobility could also lead to higher energy expenditure and potentially greater fatigue over prolonged efforts. Conversely, the reduced angular variability of the trunk suggests effective postural control, which may help stabilize the pedaling motion and prevent compensatory movements that could increase injury risk. These insights highlight the importance of monitoring kinematic patterns in Paralympic cyclists to optimize performance, design targeted strength and conditioning programs, and minimize the likelihood of overuse injuries associated with altered biomechanics.

Comment 5: Validation of the prosthesis and patent status. Since the prosthesis (Design 1.4) is central to the study: Have clinical validations or extended field tests beyond this case been conducted? Is the design undergoing regulatory processes or patent application? Adding a brief note on this would improve the translational impact of your study.
Response 5: This adjustment was made (page 15, last paragraph, lines 589–610), marked in red in the manuscript.
Updated text in the manuscript: 

Beyond the scope of this comparative case study, the optimized transtibial prosthesis (Design 1.4) has undergone preliminary field testing during the athlete’s regular training sessions to assess its durability and functional performance under real-world conditions. These extended tests have corroborated the laboratory findings, showing sustained mechanical integrity and user-reported comfort during prolonged use. However, larger-scale clinical validation involving more athletes is still needed. It should be noted that including more participants would necessarily require an individualized study for each one, as the prosthesis design depends on the specific characteristics of each athlete, such as height, weight, body composition (fat mass and lean mass), as well as the phase of their training cycle (general, specific, pre-competitive, or competitive). These variables may entail variations or adjustments in the prosthetic design to optimize performance according to individual needs. This requirement for personalized studies was precisely one of the reasons why only one Paralympic cyclist was included in the present work, as involving more subjects would have required significantly more time and much higher costs, for which the available resources were very limited.

In parallel, the design is currently undergoing the initial stages of regulatory review and intellectual property protection. A national patent application for Design 1.4 has been filed with the Colombian Superintendence of Industry and Commerce, and the research team is exploring pathways for further development and commercialization in collaboration with local biomedical engineering firms. Including these translational efforts underscores the potential of this work to inform both clinical practice and innovation in adaptive sports technology.

Comment 6: Figures and tables: Ensure that figure titles are complete and sufficiently descriptive. Consider improving the visual contrast and readability of the line graphs (Figures 5 to 8), especially where several curves overlap.
Response 6: We appreciate the reviewer’s suggestion regarding the figure captions and visual quality of the line graphs (Figures 5–8). We have revised the captions to ensure they are complete and descriptive, clearly indicating the variables displayed and the conditions of the measurements. In addition, we have improved the contrast and color differentiation of the overlapping curves in the line graphs to enhance readability, particularly for Figures 5–8.
Updated text in the manuscript: 

Figure 5: Trunk flexion–extension angles during a complete pedaling cycle in the Paralympic cyclist (upper panel) and conventional cyclist (lower panel), with right and left sides differentiated. Se realizo el ajuste (página 11, párrafo 1, líneas 375 - 376), la cual está marcada en azul en el manuscrito.

Figure 6: Hip flexion–extension angles during a complete pedaling cycle in both cyclists, highlighting possible side asymmetries. Se realizo el ajuste (página 11, párrafo 4, líneas 394 - 395), la cual está marcada en azul en el manuscrito.

Figure 7: Knee flexion–extension angles during a complete pedaling cycle in both cyclists, showing symmetries and compensatory patterns. Se realizo el ajuste (página 12, párrafo 1, líneas 416 - 417), la cual está marcada en azul en el manuscrito.

Figure 8: Ankle dorsiflexion and plantarflexion angles during a complete pedaling cycle in both cyclists, comparing functional adaptations. Se realizo el ajuste (página 12, párrafo 4, líneas 437 - 438), la cual está marcada en azul en el manuscrito.

Comment 7: Terminological consistency: Use consistent terminology throughout the manuscript (e.g., VO₂max vs. Vo₂max, RER vs. respiratory exchange ratio). Ensure that all acronyms are defined at first mention (which you have mostly done well).
Response 7: We appreciate the reviewer’s observation regarding terminological consistency. We have thoroughly reviewed the manuscript to ensure that all abbreviations and terms are used consistently throughout the text. Specifically, we standardized the use of VO₂max (instead of mixed capitalization forms such as Vo₂max), and RER (instead of the full term respiratory exchange ratio or inconsistent abbreviations) after its first definition. We also verified that all abbreviations are clearly defined at their first mention in the text.

Comment 8: Grammar and style: The language is generally clear. However, one final round of minor editing (especially in the abstract and conclusions) would improve fluency.
Response 8: We appreciate the reviewer’s positive comment on the overall clarity of the language. Following their suggestion, we conducted an additional round of minor proofreading, focusing particularly on the Abstract and Conclusions sections, to improve fluency and readability without altering the meaning of the text.

Author Response File: Author Response.pdf

Round 2

Reviewer 2 Report

Comments and Suggestions for Authors

I commend the authors for the corrections implemented. However, the main limitation of the manuscript remains: the testing was performed on only one pair of cyclists (able-bodied and para-athlete). This constrains the scope of the paper strictly to a technological innovation, rather than a broader study involving cyclists with or without motor disabilities. Accordingly, certain formulations within the manuscript should be adjusted to reflect this distinction clearly.

In this context, some key characteristics of the prosthesis should be briefly reiterated— even if previously reported in the literature— to ensure clarity in the exposition of its operational principles.

The sentence "Only minor language editing support (grammar and formatting) was provided using ChatGPT-4 for linguistic clarity" should be removed. Even the statement "No Generative Artificial Intelligence (GenAI) tools were used in data generation, study design, or analysis" may be omitted. Such a disclaimer would only be necessary in the case of explicit GenAI involvement, for instance, in data augmentation or AI model training.

Finally, if the figures are not submitted as separate high-resolution files, they will not be legible at their current size.

Author Response

Translator        

Dear Reviewer. 

We would like to inform you that we have addressed all the new recommendations provided. The corresponding revisions have been implemented and are highlighted in fuchsia throughout the manuscript for your convenience.

Comment 1: Are the methods adequately described? Are the results clearly presented? Are the conclusions supported by the results?

Response 1: We appreciate the reviewer’s positive assessment. The methods, results, and conclusions have been reviewed and slightly refined to ensure clarity and consistency.

Comment 2: The main limitation persists: the study involves only one pair of cyclists, limiting the scope to a technological innovation rather than a generalizable study. Adjust formulations accordingly.

Response 2: We revised the Abstract, Discussion, and Conclusions to explicitly state that the findings illustrate an exploratory, athlete-specific case study focused on technological innovation, and are not intended to be generalized.

Updated text in the manuscript: Abstract; These findings illustrate, in this specific case, this adjustment was made on page 1, lines 25–26, which is marked in red in the manuscript. Discussion; These findings should be understood in the context of a technological innovation case study, rather than as generalizable results. this adjustment was made on page 14, last paragraph, lines 545–546, which is marked in red in the manuscript.

Comment 3: Briefly reiterate key characteristics of the prosthesis for clarity.

Response 3: We added a sentence in Section 2.1 summarizing the prosthesis features: rigid at the ankle, customized to the athlete’s anthropometric characteristics, and designed for his pre-competitive phase.

Updated text in the manuscript: The final design was rigid at the ankle joint, fully customized to the athlete’s anthropometric measurements, optimized for competitive track cycling, and specifically tailored to his pre-competitive training phase to enhance performance during the subsequent competitive period, this adjustment was made on page 3, lines 108–112, which is marked in red in the manuscript.

Comment 4: Remove the note about ChatGPT-4 and GenAI tools. T

Response 4: The note regarding ChatGPT-4 and GenAI has been removed. 

Comment 5: Figures must be provided in separate high-resolution files.

Response 5: We have uploaded all figures in separate high-resolution (300 dpi) files as required.

We thank the reviewers and the editorial team for their constructive feedback and look forward to receiving a positive response regarding the acceptance of our manuscript in Prosthesis. Please let us know if you require any further information.

Kind regards,
Dr. Oscar Rubiano E.
On behalf of all co-authors

Please do not hesitate to contact us if you need any additional information or further clarification.

We look forward to your kind feedback on the revised submission.

Author Response File: Author Response.pdf

Round 3

Reviewer 2 Report

Comments and Suggestions for Authors

I consider that the requested revisions have been appropriately addressed, and I believe the manuscript meets the requirements for publication.