Numerical Identification of Deep Muscle Residual Tensions (Tones) Based on Multi-Directional Trunk Stiffness Data

Round 1

Reviewer 1 Report

The proposed study entitled “Numerical identification of deep muscle residual tensions 2(tones) based on multi-directional trunk stiffness data” is interesting and can be accepted for publication after minor revision.

1.     Electromyography is a popular technique used to measure muscle tones. Authors must state in their introduction why their work is superior to those traditional methods.

2.     Abstract the confusing. It must highlight the novelty and key findings of this work.

3.     Section 2. Materials and methods is important but readers are more interested in results. Therefore, common information can be shifted to the supporting information.

4.     Figure 3. Normalized tone % in direction 3. Why the trunk stiffness is higher than the other directions? Also, many details are not visible in Figure 3. Error bars can be added.

Author Response

The authors thank the reviewer for the pertinent remarks. The manuscript has been revised in light of the reviewer’s suggestions, with the modified text highlighted in yellow.

The proposed study entitled “Numerical identification of deep muscle residual tensions (tones) based on multi-directional trunk stiffness data” is interesting and can be accepted for publication after minor revision.

1/ Electromyography is a popular technique used to measure muscle tones. Authors must state in their introduction why their work is superior to those traditional methods.

-The following sentence is added to the introduction:

“For the deep muscles, unlike traditional intrusive means of tone measurement, this method is painless and safe for the subject.”

2/ Abstract the confusing. It must highlight the novelty and key findings of this work.

-The following sentence is added to the abstract:

 “In contrast, the proposed identification approach is painless and safe for the subject. It proceeds by matching the experimental trunk stiffness with numerical upper and lower estimates of the stiffness, to construct an inclusive solution domain of possible tone values of trunk superficial and deep muscles.”

3/Section 2. Materials and methods is important but readers are more interested in results. Therefore, common information can be shifted to the supporting information.

- Table 2 has been moved to Results and Analysis section, Table 3 has been moved to the Appendix A and renamed as Table A1 and Table 5 has been moved to the Results and Analysis section and renamed Table 4. Reference to these tables has been adapted in the revised manuscript to accommodate these changes.

- Subsections 2.5.1 and 2.5.2 have been replaced by a short paragraph and moved, numberless, to the beginning of the Results and Analysis section 3. The related changes have been highlighted in yellow.

4/ Figure 3. Normalized tone % in direction 3. Why the trunk stiffness is higher than the other directions? Also, many details are not visible in Figure 3. Error bars can be added.

- Experimental and numerical results show that trunk stiffness in direction 3 is higher than in the other directions. This is due to the trunk structure and muscles anatomy that makes the trunk more rigid in direction 3. An explanation can be attributed to the moment capacity given by the product of active muscle section and the moment arm. A detailed examination of the moment capacities could provide supporting evidence. As a brief indicator, the moment arm being generally largest in direction 3 is consistent with the observed result.

- The error due the regression in Figure 3, is everywhere less than 3%. This is expressed in the following sentence added in the caption:

“The error between the calculated stiffness and linear regression value is everywhere less than 3%.”

Reviewer 2 Report

This work proposes an identification methodology to estimate the residual tension values 24(tones) for the human trunk muscles, including the deep ones, using multidirectional trunk stiffness 25 data in association with numerical modeling. The role of this residual muscle tension or contraction 26 is to maintain posture and balance. 

I think the paper is written well. It includes a comparison with base methods. I think the authors need to emphasize the importance of this research with more examples of where it can make a difference.  Furthermore, for reference, the authors can add one example. 

Author Response

Thank you very much for your review. According to your suggestions, a revision of the manuscript is made. The modified parts are marked in yellow.

The authors thank the reviewer for the valuable remarks. The manuscript has been revised in light of the reviewer’s suggestions, with the modified text highlighted in yellow.

I think the paper is written well. It includes a comparison with base methods. I think the authors need to emphasize the importance of this research with more examples of where it can make a difference.  Furthermore, for reference, the authors can add one example. 

- To add clarity to the potential uses of the proposed method, the following sentence is added in the discussion:

“In contrast, for the superficial muscles, the tone can be measured easily by existing techniques [7,12-13]. While the proposed methodology provides an alternative means for estimating the tone for these muscles, it can also take advantage of the tone data provided by other techniques [12]. The superficial muscle tone data can be used as a reference in the validation of the proposed methodology by comparing the identification results with the direct measurement data. On the other hand, these data can be used as input for the identification of unmeasured tones for a specific subject. As a result, the identification problem is reduced to finding the tones of only a subset of muscles, such as the deep ones, for the subject. The proposed method can then be applied with further gain in accuracy and efficiency in estimating the unmeasured muscle tones [25].”

- The following reference was added:

-25. Ntousis T, Mandalidis D, Chronopoulos E, Athanasopoulos S. EMG activation of trunk and upper limb muscles following experimentally-induced overpronation and oversupination of the feet in quiet standing. Gait & posture. 2013 Feb 1;37(2):190-4, doi:10.1016/j.gaitpost.2012.06.028