Insights into Neuromuscular Function in Older Adults from Functional Data Analysis of Time-Dependent Handgrip Strength Curves
Round 1
Reviewer 1 Report
Comments and Suggestions for Authors• The HGS and t of variable HGS(t) and the F in Fmax should be italicized.
• electromyography (EGM) should be corrected to electromyography (EMG).
• The font size of the text in Figures 1 to 6 should be enlarged to be roughly consistent with the text size in the main body, or appropriately increased.
• Consider whether Figures 2 to 5 all need to be included/presented.
• The header texts "Units" and "Formula" in Table 1 should be centered.
• The row labels overlap with the cells in Table 5 and Table 6.
• A conclusion should be added.
Author Response
We are pleased to submit our revised manuscript entitled: “Insights into Neuromuscular Function in Older Adults from Functional Data Analysis of Time Dependent Handgrip Strength Curves.
The following major revisions were conducted
- Inclusion of a short Conclusions section
- More detailed discussion of the limitations of the study
- Clarification of practical implications in the Discussion section
- Reduction of the number of Figures presented.
- Change of the layout of the Figures implying changes in the texts that describe them
- Changes in text format and verification of consistency of terminology
In the revised manuscript all the changes are highlighted in blue color.
To the best of our ability, all the helpful reviewers’ comments have been responded to and are addressed in the point-by-point responses below in the order presented by the reviewer.
Comment 1: “The HGS and t of variable HGS(t) and the F in Fmax should be italicized.”
Response 1: Thank you for your comment. We have written the mentioned variables in italic. To adhere to the same convention of italicizing the numeric variables we have done the same to the Rates of Force Development, RFD, and time variables.
Comment 2: “electromyography (EGM) should be corrected to electromyography (EMG).”
Response 2: Thank you for pointing out this mistake. It has been corrected in the manuscript.
Comment 3: “The font size of the text in Figures 1 to 6 should be enlarged to be roughly consistent with the text size in the main body, or appropriately increased”.
Response 3: All Figures have been changed to improve their readability.
Comment 4: “Consider whether Figures 2 to 5 all need to be included/presented.”
Response 4: Thank you for this observation. Upon careful we have decided to show the plots for the segments where statistically significant differences occur between female and male curves. For completeness, plots for the Global curves are also shown. We believe that now the manuscript contains the visuals that help illustrate the evidence that supports the conclusions, without overwhelming the reader
Comment 5: “The header texts "Units" and "Formula" in Table 1 should be centered.”
Response 5: Thank you for the remark. It has been corrected in Table 1.
Comment 6: “The row labels overlap with the cells in Table 5 and Table 6”.
Response 6: The referred overlap is now corrected in Tables 5 and 6
Comment 7: A conclusion should be added.
Response 7: We appreciate this comment. We have added a short Conclusions section Moreover, to also have added, in the Discussion, a paragraph about the study limitations and another one about the implications of the findings.
Author Response File: 
Author Response.docx
Reviewer 2 Report
Comments and Suggestions for AuthorsDear Authors,
This manuscript presents an interesting methodological approach for analysing time-dependent handgrip strength curves in older adults using Functional Principal Component Analysis (FPCA) and Statistical Parametric Mapping (SPM). The topic is relevant to biomechanics and geriatric functional assessment, and the analytical framework may provide additional insight beyond conventional discrete grip strength measures.
The study is generally well designed and clearly written. The methodological pipeline combining FPCA and SPM is particularly valuable because it allows identification of temporal characteristics of force production that are not captured by traditional summary metrics.
However, several minor points should be addressed to improve clarity and interpretation:
1. Sample Size and Sex Imbalance
The number of male participants is relatively small compared with the female group. Although this limitation is mentioned in the Discussion, the authors should more clearly acknowledge how this imbalance may influence statistical interpretation.
2. Clarification of Practical Implications
While the manuscript demonstrates methodological advantages of FPCA and SPM analysis, the clinical or practical implications for geriatric assessment or rehabilitation practice could be described more explicitly.
3. Segmentation Rationale
The rationale for selecting the specific curve segments (onset–250 ms, onset–t63, t63–tmax, etc.) could be slightly clarified for readers who may not be familiar with force–time curve analysis.
4. Minor Language and Formatting Issues
A careful proofreading of the manuscript is recommended to ensure consistency in terminology and formatting across sections.
Overall, the manuscript provides a valuable methodological contribution and is suitable for publication after minor revision.
Author Response
We are pleased to submit our revised manuscript entitled: “Insights into Neuromuscular Function in Older Adults from Functional Data Analysis of Time Dependent Handgrip Strength Curves"
The following major revisions were conducted
- Inclusion of a short Conclusions section
- More detailed discussion of the limitations of the study
- Clarification of practical implications in the Discussion section
- Reduction of the number of Figures presented.
- Change of the layout of the Figures implying changes in the texts that describe them
- Changes in text format and verification of consistency of terminology
In the revised manuscript all the changes are highlighted in blue color.
To the best of our ability, all the helpful reviewers’ comments have been responded to and are addressed in the point-by-point responses below in the order presented by the reviewer.
Comment 1: Sample Size and Sex Imbalance
The number of male participants is relatively small compared with the female group. Although this limitation is mentioned in the Discussion, the authors should more clearly acknowledge how this imbalance may influence statistical interpretation.
Response 1: Thank you for pointing out this aspect. We absolutely agree that this is a major limitation, and it was never our intention to hide it. In the Discussion, we have now written a paragraph explaining the limitations of having small, unbalanced sample sizes. We have also added a short “Conclusions” section where the limitations are also referred to.
Comment 2: Clarification of Practical Implications
While the manuscript demonstrates methodological advantages of FPCA and SPM analysis, the clinical or practical implications for geriatric assessment or rehabilitation practice could be described more explicitly.
Response 2: Thank you for this comment. We have added the following text at the end of the Discussion section we have written a paragraph about the implications of the results of this study.
Comment 3. Segmentation Rationale
The rationale for selecting the specific curve segments (onset–250 ms, onset–t63, t63–tmax, etc.) could be slightly clarified for readers who may not be familiar with force–time curve analysis.
Response 3: Thank you for this comment. This segmentation follows previously published works. Details explaining the reasoning behind choosing these intervals can be found in the works cited in the part of the text where the time segments are defined. We have chosen to provide the references and not dwell longer on this explanation to render the focus of the text elsewhere. We also believe that Figure 1 helps to visualize the segmentation. Nevertheless, changes have been made in the definitions of the segments with the purpose of providing more information about it.
Comment 4. Minor Language and Formatting Issues
A careful proofreading of the manuscript is recommended to ensure consistency in terminology and formatting across sections.
Overall, the manuscript provides a valuable methodological contribution and is suitable for publication after minor revision.
Response 4. We appreciate the positive feedback. We have tried to improve the terminology and formatting across the document.
Author Response File: Author Response.docx
Round 2
Reviewer 1 Report
Comments and Suggestions for AuthorsNow I think that the revised version of the manuscript can be accepted for publication.
