Effects of Resistance Training Program on Muscle Mass and Muscle Strength and the Relationship with Cognition in Older Women

Round 1

Reviewer 1 Report

Major comments

• The power analysis should be sufficiently explained that led to choose the sample study.
• Since there was dropout during the intervention the conduction of the intent-to-treat analysis should be considered and reported in addition to completer’s analysis.
• It is unclear how authors conducted the regression analysis. This needs to be extensively explained, starting from correlation analysis. Moreover the modules should be better explained (i.e. simple). Finally did authors adjust for other confounders in the module.
• It is unclear why authors used Bonferroni correction that mainly used in multiple comparisons. Where it has been exactly used?
• The study is an interventional trial (not observational). Authors are requested to give information about the trial registration (i.e. number and link that proof that). In the same direction authors are requested to give the IRB number and the date of approval.

Other comments

• The abstract is unclear especially in presentation of results and conclusions.
• Keywords should appear in alphabetical order.
• The Introduction is long and speculative, should be shortened and focused on the aim of the manuscript.
• The discussion section is confusing. It should be re-written according to the following order:
• Main findings and their comparison with previously published available in the literature (i.e. accordance, discordance etc.).
• The main clinical implication of these finding
• Strength and limitations
• New direction for the future research

Author Response

Please see the attachment

Author Response File: Author Response.pdf

Reviewer 2 Report

Title:

Effects of resistance training program on muscle mass and muscle strength and the relationship with cognition in older women

 

The aim of the study was to examine the impact of a specific resistance training program on muscle mass and muscle strength and the relationship between changes observed in upper and lower body strength and muscle circumferences with cognition in older women.

 

Main Concerns:

-  the English throughout the manusctpt is poor. Many of the sentence structures are awkward and although this reviewer still managed to understand what the authors are trying to said – many of the written sentences clearly need to be improved. Please get an English-speaking native to vet through your paper

- the interpretation of the results. While the correlations between changes observed among muscle strength/mass with cognition levels were statistically significant, as shown in Figure 3, the variance between many of these values were really low, with values between 3 to max 15% only. Given that correlations do not imply cause-and-effect, these very low correlation/variance values could be statistically significantly purely by chance. Therefore authors would clearly need to provide good justifications as how these low values can be relevant to the aim of the study (i.e., impact of strength to cognition and vice-versa), and hence in the discussion section, the authors would need to provide some physiological mechanism(s) on how such magnitude of  improvements in strength/muscle mass can directly or indirectly improve/impact one’s levels of cognition. 

- Line 162. The test MMSE was reported to assess cognition BUT no other details of the test was mentioned in the present study. What aspects of cognition is the MMSE is measuring? What about the reliability and validity of the MMSE test in measuring and assessing these aspects of cognition – none of these were not reported or described? No mention what higher or lower values imply in regards to levels of cognition.

 

Minor issues:

- Lien 16. Start with a clear sentence, “The aim of the study …..”

- Line 21. The type of strength training should be provided here.

- Table 1. Use body mass and stature rather than weight and height.

- Figure 1. Use the term, Dropped out in “the first year of the study”.

- Line 110. Delete “extraordinary”.

- Line 116. Change to “….  (iv) women who were involved in any systematic exercise programme and/or physical activity within 5 years prior to the beginning of the study;…”

- Line 118. “……. (vi) no previous diagnosis of cognitive deterioration or muscle mass loss; ….” How was this determined in the present study?

- Line 125. Estimations of 1RM of what? Sentence structure is poor here. The term “Phases” should  in lower cap.

- Line 129. Change “adaptation” to “assessment”. Change “in” with “of”. I think “sets” is a better word than “series”.

- Line 132-134. This is not clearly written. The load imposed on the individual is solely based on the individuals’ OMNI scale (which is a subjective perception of load/stress), which the authors equate to be around 20-30% of the individual’s 1RM. Hence, my query is: Was the individual’s 1RM load estimated from their submaximal lifts – and if so, how reliable is this estimation value. Authors need to provide some validated published study to justify the manner or protocol of this 1RM load estimation in the older population.  

- Line 136. Delete “theoretical” and replace with “individual’s”.

- Line 136. During the “next week” – another poorly written sentence.

- line 150, what is the “aerobic exercise” – is it running or cycling or what?

- Should Figure 1 and not Picture 1.

- Who monitored and supervised the resistance training sessions to ensure the compliance to the  programme?

- Line 169. Is the person assessing the circumferences of the arm and calf trained to do this task well. For example, is the individual certified ISAK? What is the individual’s’ coefficient of variation measurement values?

- Line 176. Is it ‘BMI’ or should it be ‘lean mass’?

- Table 3 and Table 4 should be combined into a single table.

 

Author Response

Please see the attachment

Author Response File: Author Response.pdf

Reviewer 3 Report

The present study investigated the effects of a two-year resistance training programme on muscle morphology and strength, as well as on cognitive functions in a population of older women. The study is interesting and covers a topic that is worth being investigated. The manuscript is well-written and structured. Introduction and Discussion are clear and complete. Methodology and results are well-described. I would congratulate the Authors for their work. Here some suggestions and comments that I hope will be useful to improve the scientific quality of the manuscript.

• The duration of the exercise programme (two years) is a great value for the study. However, I do believe that the addition of another group to the study (maybe participating in other kind of exercise programme) would have contributed to increase the value of the study.
• Did the Authors consider to evaluate possible changes in the quality of life? It plausible that an exercise programme based on resistance training will induce positive outcomes also on the quality of life. This can be considered to include in the Discussion section for further studies on the same topic.
• Line 16. Rephrase. “The aim of the present study was…”
• Please include a paragraph stating the practical applications derived from the present study, highlighting how this study can be useful for practitioners and for implementing exercise programmes in healthy policies.

Author Response

Please see the attachment

Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

Authors was not responsive to major comments. 

Author Response

All the questions from reviewer 1 have been answered,  we don't understand this report:

Major comments

THE REVIEWER WRITTEN

• The power analysis should be sufficiently explained that led to choose the sample study.

RESPONSE ROUND 1: Thank you for the comment. As can be seen in Figure 1 and in the Participants subsection this research carried out a non-probabilistic sampling procedure. All potential participants were contacted initially.

EXPLINATION ROUND 2.

The power analysis that led to choose the sample, cannot we explained, because all potential participants were initially included, we don’t know if the reviewer wants a power analysis a posteriori, because if is not a probabilistic study, if all potential participant were initially included

 

THE REVIEWER WRITTEN

• Since there was dropout during the intervention the conduction of the intent-to-treat analysis should be considered and reported in addition to completer’s analysis.

RESPONSE ROUND 1:

Thank you for your comments. In our opinion and according to Lewis et al. (1993) the ITT analysis does not apply in this paper for the following reasons:

1. Firstly, it is a rarely used analysis and, in addition is controversial
2. It is especially recommended to clinical trials; this is not the case.
3. All participants satisfy all entry criteria from the beginning to the end of intervention.
4. All participants included in the analysis completed their allocated exercises program, no group switching.
5. We don't have monitoring of dropped-out participants

Lewis, J. A., & Machin, D. (1993). Intention to treat--who should use ITT?. British Journal of Cancer, 68(4), 647–650. https://doi.org/10.1038/bjc.1993.402

EXPLINATION ROUND 2.

In our opinion, the reviewer analysed this paper as a Clinical trial, but this is not a clinical trial. We don't know why the reviewer required an ITT analysis. It is not possible in this design. In addition, as we explained previous response (with references), this analysis is controversial, in fact, in research about intervention with exercise training programs it is very infrequent.

 

THE REVIEWER WRITTEN

• It is unclear how authors conducted the regression analysis . This needs to be extensively explained, starting from correlation analysis. Moreover the modules should be better explained (i.e. simple). Finally did authors adjust for other confounders in the module.

RESPONSE ROUND 1:

Thank you very for your comment. The regression analysis conducted was a simple (bivariate) linear regression. Corrected (line 208 and line 264)

EXPLINATION ROUND 2  SENTENCE BY SENTENCE.

• It is unclear how authors conducted the regression analysis . The regression analysis conducted was a simple (bivariate) linear regression

 

• This needs to be extensively explained, The regression analysis conducted was performed in SPSS. Does Referee want that the authors explain in the paper how to run a simple (bivariate) linear regression with SPSS??

 

• starting from correlation analysis. A correlation analysis have not performed

 

• Moreover the modules should be better explained (i.e. simple). Finally did authors adjust for other confounders in the module. It is s a bivariate regression the are not modules.

 

 

 

THE REVIEWER WRITTEN

• It is unclear why authors used Bonferroni correction that mainly used in multiple comparisons. Where it has been exactly used?

RESPONSE ROUND 1:

Thank you very much for your comment. It is an error. Corrected (statistical analysis subsection).

EXPLINATION ROUND 2  

Bonferroni correction was not carried out, it was an error. The statistical analysis was corrected:

THE REVIEWER WRITTEN

• The study is an interventional trial (not observational). Authors are requested to give information about the trial registration (i.e. number and link that proof that). In the same direction authors are requested to give the IRB number and the date of approval.

RESPONSE ROUND 1:

We agree with the referee, this is an interventional trial (not a clinical trial), in fact in Material and Methods section, we can read (lines 98-99):

“2.1. Design”

“This was a two-year, experimental, non-probabilistic, longitudinal study”.

 

The report was send to Editor with the original manuscript, in any case, at the end of the manuscript, in Institutional Review Board Statement section, we can read (lines 390-392):

The study was conducted according to the guidelines of the Declaration of Helsinki and approved by the Institutional Ethics Committee of University of Santiago de Chile (Informe Ético Nº 140, data of approval: 17 April 2017).

 

EXPLINATION ROUND 2 SENTENCE BY SENTENCE.

The study is an interventional trial (not observational). Of course, the authors never written about this paper as an observational trial, we don't' understand why the referee said that?

• Authors are requested to give information about the trial registration (i.e. number and link that proof that).

This study is not a clinical trial, so it is not required a registration.

 

• In the same direction authors are requested to give the IRB number and the date of approval.

The study was approved by the Institutional Ethics Committee of University of Santiago de Chile (Informe Ético Nº 140, data of approval: 17 April 2017).

Reviewer 2 Report

• the authors did not response to my query on the interpretation of the results adequately.
• My point is that while the correlations between changes observed among muscle strength/mass with cognition levels were statistically significant, as shown in Figure 3, the variance between many of these values were really low, with values between 3 to max 15% only. Given that correlations do not imply cause-and-effect, these very low correlation/variance values could be statistically significantly purely by chance. Therefore authors would clearly need to provide good justifications as how these low values can be relevant to the aim of the study (i.e., impact of strength to cognition and vice-versa), and hence in the discussion section, the authors would need to provide some physiological mechanism(s) on how such magnitude of  improvements in strength/muscle mass can directly or indirectly improve/impact one’s levels of cognition. 
• the authors should highlight this small magnitude of variance in the key variables as a limitation in the present study stating that significant correlation does not imply cause-and-effect and readers should interpret these findings with caution.

Author Response

"Please see the attachment."

Author Response File: Author Response.pdf

Round 3

Reviewer 2 Report

no other changes required