Modified Ankle Joint Neuromechanics during One-Legged Heel Raise Test after an Achilles Rupture and Its Associations with Jumping

Round 1

Reviewer 1 Report

The authors analysed an interesting theme, especially for the functional rehabilitation of the patients with Achilles lesions.

As stated by the authors, care must be taken in interpreting the results, since there is no control group.

Author Response

Reviewer 1

R1-1 Comments and Suggestions for Authors

The authors analysed an interesting theme, especially for the functional rehabilitation of the patients with Achilles lesions.

Responses to R1-1

We are very grateful for the reviewer’s consideration and hope that this study will make substantial contributions to the functional rehabilitation of the patients with Achilles repair. In this amended version, we have added a potential clinical application of the research findings regarding the prevention of re-rupture. The relevant text reads as follows:

Collectively, these correlations suggest that enhancing soleus muscle activation may be effective in terms of energy storage and enhancing movement efficiency, and the eccentric strengthening of the soleus could prevent excessive mechanical energy from being dissipated by the Achilles tendon and, thereby, reduce the risk of re-rupture.

Please see the revised text on page 10, lines 304-306.

R1-2 As stated by the authors, care must be taken in interpreting the results, since there is no control group.

Responses to R1-2

We appreciate the reviewer’s reminder. We have sought to be very cautious in the discussion and to avoid overgeneralizing the research results, as the findings might not be transferable to clinical practice.

Reviewer 2 Report

ApplSci-1020481

Reviewer’s Comments

In the submitted manuscript, the authors study the kinemetic, kinetic and electromyographic parameters in a one-legged heel-raise test in both the injured and non-injured lower limb in 26 participants after a unilateral Achilles repair. The authors also tested the correlation between the EMG results and the dynamic characteristics and the correlation between the characteristics in the eccentric phase of the one-legged heel-raise test and the normalized to body height hopping distance. Results revealed that inter-limb differences were observed for the majority of the parameters. These differences were attributed to the observed neuromechanical changes in m. soleus after the repair.

The research is within the scope of the Section of the Journal. However, there are some issues that need to be addressed in order to consider this study for publication.

General comments

• Parts of the text should be relocated within the manuscript, as indicated in the Specific Comments.
• Materials & Methods:

1. EMG analysis: define the onset and offset of the signal.
2. In addition, describe the method to define the threshold values of the EMG prior the actual testing task and how the onset of the actual activation was defined.
3. Was the knee joint angle controlled during the heel-raise test? M. gastrocnemius, as a biarticular muscle might present altered neuromuscular behaviour due to a possible alteration of the knee joint angle during the test.
4. Were data acquired during the one-legged forward jumping test? What is the rationale to correlate the performance in the one-legged forward jumping test with the neuromechanical parameters recorded in the one-legged heel-raise test rather than the hopping test per se?
5. Based on the data acquired, could a co-activation index [ Ervilha, U.F., Graven-Nielsen, T., & Duarte, M.. (2012). A simple test of muscle coactivation estimation using electromyography. Brazilian Journal of Medical and Biological Research, 45(10), 977-981] add content in the discussion of the results?

• Statistical analysis: What was the test to do the comparison of the data obtained for the concentric and eccentric phases?
• Results: Information concerning the descriptive results of the kinetic and kinematical parameters examined is missing.
• As the ankle joint dorsi flexion is a factor affecting jumping performance [ ● Godinho, I., Pinheiro, B. N., Júnior, L. D. S., Lucas, G. C., Cavalcante, J. F., Monteiro, G. M., & Uchoa, P. A. G. (2019). Effect of reduced ankle mobility on jumping performance in young athletes. Motricidade, 15(2-3), 46-51. ● Papaiakovou, G. (2013). Kinematic and kinetic differences in the execution of vertical jumps between people with good and poor ankle joint dorsiflexion. Journal of Sports Sciences, 31(16), 1789-1796 ● Yun, S. J., Kim, M. H., Weon, J. H., Kim, Y., Jung, S. H., & Kwon, O. Y. (2016). Correlation between toe flexor strength and ankle dorsiflexion ROM during the countermovement jump. Journal of Physical Therapy Science, 28(8), 2241-2244], it is suggested to discuss the mechanisms that may contribute to the findings of the study referring the range of motion and the flexibility of the muscles acting about the ankle joint.

Specific comments

Title

• L2-3: It seems that a verb is missing. It is recommended rewrite the Title.

Abstract

• Although the Abstract length is exactly 200 words, as the word limit indicated by the Journal’s instruction for authors (https://www.mdpi.com/journal/applsci/instructions), it is suggested to remove the range of the p values and to indicate the parameters where significant differences were noted.
• L23-26: It is suggested to rewrite this sentence – there is too much information that confuses the reader.
• L27: ...prior the measurement...
• L28-29: with EMG, multiple-dimensional motion analyses, and force plate. It is suggested to rewrite this phrase, as it describes the instrumentation rather than the parameters to study the one-legged heel-raise test. In addition: multiple-dimensional motion analyses = 3D analysis.

Introduction

• L42: individuals instead of “those”.
• L46: ...Achilles tendon lengthening in the involved leg…
• L55: ...demonstrating electromyographic (EMG) activity...
• L59: Change paragraph at “The eccentric phase”.
• L69-71: Elaborate on this statement.
• L71: ...test, which was not explicitly explained in the existing literature. Also: provide citations for this statement.
• L72: Rewrite the phrase “This approach also provides allows us to assess”.
• L78-79: ... kinematic and kinetic characteristics...
• L80: the relationship instead of “correlations”.

Materials and Methods

• See the respective General Comments.
• L106: Insert a subsection: “2.1 Participants” and renumber the following subsections.
• L131: ... were placed and fixed...
• L142-143: How was the starting point of each phase estimated? As they were defined depending on spatial parameters, it is suggested to refer to an upward and downward phase.
• L143: Provided details about the “controlled manner” of the execution of the test.
• L147: Was the knee angle change during the test an exclusion criterion? (see also the respective General Comment).
• L148-150: Place this sentence after L143.
• L155-156: ...of the muscles, the RMS amplitudes of the ground reaction force (GRF) and mechanical work
• L161-162: Place this sentence after L158.
• L170-182: Place Figure 2 in the results section. 
• L197-200: Provide parts of this information in the proposed subsection “2.1 Participants” (see the comment for L106).
• L201: Name the parameter(s) were the Kolmorogov-Smirnov test revealed lack of normality.
• L208: ... IBM Statistical Package for Social Sciences Statistics, version 22.0 (IBM Inc, Armonk, NY).

Results

• See the respective General Comment.
• L211-212: Place this sentence in the proposed subsection “2.1 Participants” (see the comment for L106).
• L224-228: Place Table 1 in the proposed subsection “2.1 Participants” (see the comment for L106)..
• L224: Characteristics [reported as means (range)]...
• L235: significant difference.
• L236: Spearman rank correlation coefficients between...

Discussion

• L306-339: See the respective General Comment.

Conclusions

• Provide specific suggestion based on the findings of the present study.

Comments for author File: Comments.pdf

Author Response

Please find the attached document for our responses to the reviewers' suggestions.

Author Response File: Author Response.doc

Reviewer 3 Report

The authors present an interesting proposal on the analysis of muscle activation, kinetics, and kinematics during the one-legged heel raise test after an Achilles rupture. I believe that the authors should make an effort to improve the clarity of each of the sections and to expand the statistical analysis.

General comments:

The authors abuse long sentences that make reading difficult (e.g. l21-26; ln83-87; ln 247; 251. I suggest that they propose 2 hypotheses aligned with the 2 objectives, and rephrase those sentences that make the reader get lost.

The authors, on the one hand, compare the EMG by phase between injured and uninjured legs and, on the other, establish correlations. I believe that the correlation analysis is insufficient for the stated objective, and these results have to be based on a regression analysis that can identify relationships in a better term. This must be considered in both methods and results. Besides, while in the statistical analysis they determine that they use Spearman, in the table they put "Correlations are presented as r values". They should put more interest and care into this.

Lastly, the language must be thoroughly reviewed.

Specific comments:

Ps ranged change to p's range (p in italics and lowercase).

ln71 The authors say "(which was not explicitly explained in the existing literature)". These statements must be defended and not expressed in those terms.

ln75-75 This information corresponds to methods.

ln251-254 Statements such as "The correlation results demonstrated that the muscle activations in the medial gastrocnemius and soleus muscles were respectively associated with the total ankle angle in the concentric phase and the negative work in the eccentric phase of the OLHR test." they can be done if the regression analysis is consistent with the correlation analysis.

Author Response

Please find the attached document for our responses to the reviewers' suggestions.

Author Response File: Author Response.doc

Round 2

Reviewer 2 Report

applsci-1020481 – Resubmission

Reviewer’s Comments on Authors’ response

In the resubmitted manuscript, the authors provide an improved version and address the recommendations of the reviewers. The resubmitted manuscript is considerably improved, but still several issues should be clarified, as pointed out in the comments on the authors’ point-to-point response below and the General comments.

Comments on authors’ response

• Responses to R2-2.1 (also R2-9.3). Based on the description, the movement can be further divided in the ‘downward’ and ‘upward’ phase rather than to the ‘eccentric’ and ‘concentric’ phase, as this division is based on directional movements and not on a suspected change of muscle fibre length (elongated and shortened, respectively).
• Responses to R2-2.3 (also R2-9.4). knee joint angle: authors should be more specific if the straight knee was evaluated visually or there was video-analysis data to provide evidence for the lack of knee joint flexion. How were the data synchronized?
• Responses to R2-2.4 (also R2-8.5 and R3-6). This is the weakest point of the study. There is no indication that the biomechanics of one limited, constrained vertical movement can interpret the biomechanics of an explosive horizontal movement. Rather than a correlation, a regression analysis might provide a base to elaborate on the rationale of the study.
• Responses to R2-2.5. Lack of co-activation index: include this in the limitations of the study.
• Responses to R2-5. The revised text on page 11, line 338; lines 341-344: Provide citations. Once again, it is suggested to use the findings and the discussion of the following papers:
• Godinho, I., Pinheiro, B. N., Júnior, L. D. S., Lucas, G. C., Cavalcante, J. F., Monteiro, G. M., & Uchoa, P. A. G. (2019). Effect of reduced ankle mobility on jumping performance in young athletes. Motricidade, 15(2-3), 46-51.
• Panoutsakopoulos, V., Kotzamanidou, M. C., Papaiakovou, G., & Kollias, I. A. (2021). The ankle joint range of motion and its effect on squat jump performance with and without arm swing in adolescent female volleyball players. Journal of Functional Morphology and Kinesiology, 6(1), 14.
• Papaiakovou, G. (2013). Kinematic and kinetic differences in the execution of vertical jumps between people with good and poor ankle joint dorsiflexion. Journal of Sports Sciences, 31(16), 1789-1796.
• Yun, S. J., Kim, M. H., Weon, J. H., Kim, Y., Jung, S. H., & Kwon, O. Y. (2016). Correlation between toe flexor strength and ankle dorsiflexion ROM during the countermovement jump. Journal of Physical Therapy Science, 28(8), 2241-2244.
• Responses to R2-6. The suggestion is “Modified ankle joint neuromechanics during one-legged heel raise test after an Achilles rupture and its associations with jumping”.
• Responses to R2-9.9. Besides presenting the methodological issue stressed by the authors, Figure 2 depicts the results of the study. As such, it is recommended to place Figure 2 in the Results.
• Responses to R2-10.3. Range: it was not meant to report the range between the minimum and maximum for each value, but the interquartile range.

General Comments

• In subsection 2.5, you mention the LEFS-TC questionnaire, but no results are reported.
• Conclusions: enrich this section with the adaptations made in the manuscript for addressing R2-2.4, R2-8.5 and R3-6.

Comments for author File: Comments.pdf

Author Response

Please find the attached document for further detail.

Author Response File: Author Response.doc

Reviewer 3 Report

All comments have been adequately answered. Congratulations.

Author Response

We greatly appreciate these beneficial interactions during the revision process.

Round 3

Reviewer 2 Report

applsci-1020481 – 2nd Round Revised Version

Reviewer’s Comments on Authors’ response

In this version of the manuscript, the authors addressed the vast majority of the topics mentioned in the previous version. There are still some considerations as pointed out in the following Comments.

• L34: (r_s = 0.467 and -0.537, respectively).
• L34-35: Define the dynamic data in the eccentric phase. You mention 2 coefficients. Which one stands for what parameter in detail? Or do you mean between the “kinematic (ankle angular velocity) and kinetic (mechanical work) results in the eccentric phase with the normalized distance results of the one-legged jumping test (r= .575, and -.471, respectively)”as you state in L333-335?
• L205: Provide the appropriate sign in the phrase P-value 0.01.
• Results & Table 1: Check for all reported non parametric data, besides the interquartile range, if the appropriate the median rather than the mean value is presented.
• L335: Correct the Spearman rank correlation coefficient symbol (r_s).
• L344-345: mobility (ankle range of motion) vs. flexibility (mainly ankle plantar and dorsi flexor muscle function): Elaborate the discussion on both factors and their association with jumping ability.

Comments for author File: Comments.pdf