Far-Infrared-Emitting Fabric Improves Neuromuscular Parameters in Humans: Unexpected Result from Eccentric Exercise-Induced Muscle Damage Countermeasure Strategy

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

The manuscript has the following major limitations:

 

The aim of the present investigation was to test far-infrared emitting fabric (FIR) as an intervention to reduce changes in respond to exercise induced muscle damage. However, it is concluded that FIR improved neuromuscular parameters in eccentric exercise, suggesting a potential ergogenic effect. It is clear that there is a shift in focus which makes the narrative of the study a bit fragmented.

The study design is not clear at all. The two phases are described as having a crossover, double-blind, placebo-controlled design, but the samples are different, this mean that the phase 2 is an independent study which does not confirm the findings of the phase 1. However, it is not clear in the figures the two phases of the present investigation, while it seems that the results of the two phases are presented together.

Given the fact that the eccentric exercise protocol was not effective in causing muscle damage (no change in CK or MVIC in either condition), it means that the aim of the study was not achieved, so it is not meaningful of the use of FIR since there is no muscle damage to prevent.

In the Discussion the performance improvement are related to COX activation, ATP production, Ca²⁺ handling, and fatigue mitigation via PBM, which are possible mechanisms, however, none of these parameters were measured. Similarly, the link between FIR, increased EMG, and selective recruitment of high-threshold units is interesting but remains speculative.

Author Response

Author's Reply to the Review Report (Reviewer 1)

 

Dear Reviewer,

We are deeply grateful for your insightful review and valuable comments, which significantly enhanced the clarity, rigor, and overall narrative of our manuscript.

We have diligently addressed all suggestions. Our revisions focused on improving the description of ideas and results, strengthening the storytelling, and elevating the writing style. Specifically, we performed a comprehensive English revision, refined figures and legends, added statistical details and corresponding results, and clarified mechanistic speculations in the Discussion.

Detailed responses to each comment are provided below, with revisions highlighted in yellow in the re-submitted files. Please note that while the entire manuscript benefited from general stylistic improvements, only substantial content or structural changes are marked.

We are confident that these revisions have considerably improved the manuscript.

Sincerely,

Point-by-point response to Comments and Suggestions for Authors

Reviewer: “The aim of the present investigation was to test far-infrared emitting fabric (FIR) as an intervention to reduce changes in respond to exercise induced muscle damage. However, it is concluded that FIR improved neuromuscular parameters in eccentric exercise, suggesting a potential ergogenic effect. It is clear that there is a shift in focus which makes the narrative of the study a bit fragmented.”

Author's Reply: We fully agree that the unexpected findings and the shift in focus of the study left the narrative fragmented. To resolve this issue, important sections of the introduction, experimental design, and discussion were rewritten.

 

Reviewer: “The study design is not clear at all. The two phases are described as having a crossover, double-blind, placebo-controlled design, but the samples are different, this mean that the phase 2 is an independent study which does not confirm the findings of the phase 1. However, it is not clear in the figures the two phases of the present investigation, while it seems that the results of the two phases are presented together.”

Author's Reply: We revised the entire description of the experimental design to improve clarity (lines 100 - 120), explaining how both phases were performed with this design, the blinding process, and when the results are presented separately by phase or combined. The end of the introduction, as well as the section on statistical analysis, has been improved to aid in understanding the study. The N value for each analysis was also included in the table titles and figure captions.

 

Reviewer: “Given the fact that the eccentric exercise protocol was not effective in causing muscle damage (no change in CK or MVIC in either condition), it means that the aim of the study was not achieved, so it is not meaningful of the use of FIR since there is no muscle damage to prevent.”

Author's Reply: We fully agree with reviewer comment. This fact was discussed in the topic "4.1 Study Phase 1: FIR effects on muscle damage" (lines 293 - 322) seeking to identify the reasons why our protocol was unable to generate muscle damage. This fact was also recognized as a limitation in section 4.3: Limitations (lines 370 - 390).

 

Reviewer: “In the Discussion the performance improvement are related to COX activation, ATP production, Ca²⁺ handling, and fatigue mitigation via PBM, which are possible mechanisms, however, none of these parameters were measured. Similarly, the link between FIR, increased EMG, and selective recruitment of high-threshold units is interesting but remains speculative.

Author's Reply: We again fully agree with reviewer comment. It was highlighted at various points in the discussion where the sentences dealt with the authors' ideas and speculations. Additionally, this point was added to the topic of limitations. (lines 370 - 390).

Reviewer 2 Report

Comments and Suggestions for Authors

Attachment please find the comments.

Comments for author File: Comments.pdf

Author Response

Dear Reviewer,

We are deeply grateful for your insightful review and valuable comments, which significantly enhanced the clarity, rigor, and overall narrative of our manuscript.

We have diligently addressed all suggestions. Our revisions focused on improving the description of ideas and results, strengthening the storytelling, and elevating the writing style. Specifically, we performed a comprehensive English revision, refined figures and legends, added required statistical details and corresponding results, and clarified mechanistic speculations in the Discussion.

Detailed responses to each comment are provided below, with revisions highlighted in yellow in the re-submitted files. Please note that while the entire manuscript benefited from general stylistic improvements, only substantial content or structural changes are marked.

We are confident that these revisions have considerably improved the manuscript.

Sincerely,

 

Point-by-point response to Comments and Suggestions for Authors

 

Reviewer: “1. The authors should explain why the first phase was insufficient to support a definitive conclusion and why an additional, independent sample was required.”

And

“4. The authors should provide additional statistical analyses to demonstrate that the current sample size is sufficient to support the reported statistical significance.”

 

Author's Reply: We are grateful for your insightful comment regarding the study's design and sample calculation. Indeed, the initial phase yielded an unanticipated increase in performance following the eccentric exercise protocol, a finding we consider novel in the context of prophylactic strategies for EIMD. This unexpected outcome prompted the recruitment of a second sample of participants for Study Phase 2, serving the dual purpose of expanding the overall sample size and enabling the measurement of complementary neuromuscular variables, such as electromyography (EMG) activity.

To enhance clarity regarding the execution of both study phases and the rationale for the sample recruitment in Phase 2, we have implemented several revisions within the manuscript:

• The experimental design section has been thoroughly revised (lines 100-120) to provide a clearer description of how the two study phases were conducted. This now includes details on the blinding process and specifies when results are presented separately by phase or combined.
• Improvements were also made to the final part of the Introduction (lines 78-84) for better contextualization.
• Furthermore, the sample size calculation process for Phase 2 has been explicitly detailed in the Statistical Analysis section (lines 207-226).

 

Reviewer: “2. The authors should strengthen the explanation for the insufficient induction of EIMD.”

 

Author's Reply: We fully agree with reviewer comment. This fact was discussed in the topic "4.1 Study Phase 1: FIR effects on muscle damage" (lines 293 - 322) seeking to identify the reasons why our protocol was unable to generate muscle damage. This fact was also recognized as a limitation in section 4.3: Limitations (lines 370 - 390).

 

Reviewer: “3. The manuscript presents inconsistencies and logical issues in its statistical methods.”

 

Author's Reply: The Statistical Analysis section (lines 207-226) has been thoroughly revised to provide a clearer description of how the two study phases were analysed.

 

Reviewer: “5. The authors should reorganize the discussion section to better adjust and clarify the main points of the narrative.”

 

Author's Reply: We appreciate the suggestion. The discussion topic has been reorganized and improved. For this reason, most sections have been highlighted in yellow.

 

Reviewer: “6. The manuscript contains several issues related to English expression, including grammar, verb tense consistency, and overall clarity. For example: The abstract presents multiple inconsistencies in verb tense. AND Several sentences in the Introduction are overly long and lack precision and affecting clarity. AND In the participants' description, the phrase "Twenty-one young physically active participants (14 man / 7 women...)" contains grammatical errors (e.g., "man" should be "men").”

 

Author's Reply: We appreciate your comment and would like to clarify that the entire manuscript has been thoroughly revised. The revision aimed to improve the quality of the language and to enrich it with details, enhancing the narrative and clarity of the study.

 

Reviewer: “7. There are several issues with the figures and tables that need correction. Specifically: Figures 1 and 2 do not clearly indicate the sample sizes ("n = 9" or "n = 12"), which should be explicitly stated. AND The units on the axes are not presented consistently and should be standardized according to SI conventions. AND The figures lack complete and informative legends, including explanations for symbols, statistical significance markers, and variable definitions.

 

Author's Reply: We are grateful for your comment. The sample size for each analysis was included in the table titles and figure legends. The units on the axes were standardized for each variable, and compliance with SI conventions confirmed. Legends were also improved.

 

Reviewer: “8. The references are inconsistently formatted and lack recent references.”

 

Author's Reply: We used Zotero to improve precision on citation and references list

Round 2

Reviewer 1 Report

Comments and Suggestions for Authors

No further comments

Reviewer 2 Report

Comments and Suggestions for Authors

No more comments.