Effects of Advanced Age and Parkinson’s Disease on Joint-Level Kinetic Adaptations to Faster Walking Speeds

Round 1

Reviewer 1 Report

Abstract:

The essential statistical results must be added to the abstract.

Introduction:

The gap must be clearly described.

 

2.1

How was the sample size estimated, and what is the sampling method?

Is there any registered ethics code for the experiment? In this case, please specify.

2.2

Matlab and R versions must be provided, and proper citation must be added to R.

Eq. 1,2,3 : use the multiplication symbol instead of .

2.5

The statistical method is suitable. However, I wonder whether the authors check the repeated measurement ANOVA assumption.

Also, it is necessary to report the F_a,b statistics whenever the p-value of the repeated measurement ANOVA is mentioned in the results.

Figure 1: The significant results must be shown by proper symbols.

Figure 3. It is interesting to report the correlation between Old, PD, and Young waveforms for each subplot.

Tables 1 and 2: The number of digits after the decimal point must be the same for P values.

 

Author Response

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Author Response File: Author Response.pdf

Reviewer 2 Report

General Comments:

• The main purpose of this investigation was to demonstrate functional changes of those with PD at the ankle with increasing speed.
• Although I found this study unique there are a number of concerns that need to be addressed before further consideration.
• Main Concerns:
  • Your second hypothesis states that healthy older adults would exhibit disproportionately greater redistribution of mechanical work across progressively faster walking speeds compared to both healthy younger adults and individuals with PD. However, .8,1.2, and 1.6m/s were used for the treadmill trials. With set speeds it is possible that the research team artificially disrupts the participants' natural walking. Why did the authors choose these speeds and not go with self selected speed (as it can simulate normal conditions) and then 10 to 20% increase or decrease of that speed. 
  • The authors measure kinetic and kinematic data during gait of young, old, and PD while on a treadmill. Although the treadmill allows for consistent speed it does not reflect natural gait and is inappropriate for making claims about natural alterations. It is commonly accepted that the observation of normal or natural gait should be done overground and avoid using a treadmill. The authors need to address their points further to give a viable explanation.
  • There were no measures of strength in this study and so it is unknown as to how the change in walking speed reflected the participants' relative efforts. The results yielded high amounts of variability and this could be one rationale for this. The authors should examine or address the strength levels to some extent in order to make their findings more clear. 
  • I don’t feel like your conclusion actually fully restates your hypothesis or concisely restates your results, instead it tells you what the article discusses and vaguely expresses some of your results. Rework this to restate your hypothesis and briefly state important results, and how these results can impact the field. 
• Minor Concerns
  • Grammar and spell check the entire document
  • Introduction
    • Rephrase 2nd sentence to make it clearer.
  • Methods
    • Replace “heathy” with “healthy”
    • Was a current physical activity quantified for the participants or any those participants actively engage in treadmill walking, before or during testing. Someone who meets the minimal inclusion criteria and someone that exceeds will have drastic differences in their performance. The authors should address this.
  • Discussion
    • The authors' should not over exaggerate their results. They claim their results reflect motor “inflexibility” during locomotion, as they maintained similar redistribution ratios across all three speeds tested here. Their results were limited to joint distribution and inflexibility reflects multiple domains of the nervous system as well. This claim should be reworded to accurately reflect their results.

Author Response

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Author Response File: Author Response.pdf

Reviewer 3 Report

Thanks for recommending me as a reviewer. In this study, authors purpose was twofold. First, we tested the hypothesis that advanced age, regardless of the presence of PD, reduces the extent to which individuals can increase motor-like behavior of the ankle plantarflexors across progressively faster walking speeds. Second, authors tested the hypothesis that healthy older adults would exhibit disproportionately greater redistribution of mechanical work across progressively faster walking speeds compared to both healthy younger adults and individuals with PD. If authors complete minor revisions, the quality of the study will be further improved.

1. page 2: The introduction section is well written. However, the theoretical background is mostly the results of previous studies by the authors. If the authors describe the trends of other research in more detail in the introduction section, it can help readers to understand them.
2. page 2, "2.1. Participants": Authors should be more specific about Participants.
3. It is recommended that the last paragraph of the discussion section be split into a conclusion section.

Author Response

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Author Response File: Author Response.pdf

Reviewer 4 Report

In this paper, the authors aim to test: 1) the hypothesis that advanced age, regardless of the presence of PD, reduces the extent to which individuals can increase motor-like behavior of the ankle plantarflexors across progressively faster walking speeds; 2) the hypothesis that healthy older adults would exhibit disproportionately greater redistribution of mechanical work across progressively faster walking speeds compared to both healthy younger adults and individuals with PD.

The paper is easy to read and insightful.

Introduction

In the introduction I would add only a few references to underline the develop of innovative protocols to treat patients with Parkinson’s Disease:

 

Bevilacqua R, et al. Rehabilitation of older people with Parkinson's disease: an innovative protocol for RCT study to evaluate the potential of robotic-based technologies. BMC Neurol. 2020 May 13;20(1):186. doi: 10.1186/s12883-020-01759-4

Materials and Methods

This session is well written and structured.

Just only two considerations:

• I suggest to insert a table with baseline demographic and clinical data of participants
• it would be interesting to insert an image with the experimental set
• describe in more detail the acquisition protocol, also specifying the duration of the exercise

 

Results

This section is comprehensive, clear and well structured.

 

Discussion

This session is well structured. I suggest you add some references to point out that these findings have already been found in other populations during different tests:

Maranesi E, et al. The surface electromyographic evaluation of the Functional Reach in elderly subjects. J Electromyogr Kinesiol. 2016 Feb;26:102-10. doi: 10.1016/j.jelekin.2015.12.002.

 

 

 

 

Author Response

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Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

The authors addressed most of the reviewer's comments. however, the following issues must be corrected, prior to the publication of the paper:

1. As the reviewer mentioned before, the F_a,b must be provided when using repeated-measurement ANOVA. The standard notation must be used. It is not enough to report F value (as ANOVA), and á' and 'b' parameters must be provided in repeated-measurement ANOVA. The authors are required to check the related guidelines and provide F(a,b) instead of F values; [F(dftime, dfError(time)]; https://www.sheffield.ac.uk/polopoly_fs/1.531222!/file/MASH_repeated_measures_ANOVA_SPSS.pdf
2. As the authors replied in the response letter, no formal sample size estimation and random sampling methods were used in this study. Possible biases and limitations must be provided in the discussion, accordingly.

Author Response

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Author Response File: Author Response.pdf

Round 3

Reviewer 1 Report

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