Test-Retest and Minimal Detectable Change in the Assessment of Muscle Strength and Muscle Power in Upper and Lower Extremity Exercises in 9- to 14-Year-Old Children

Round 1

Reviewer 1 Report

An article on an interesting and rarely discussed topic. A large research group. I have a few comments: Please check the punctuation throughout the text. Add “...children” in the title. Introduction: line 69-70, please add that it is also important for physiotherapists, patients, parents and athletes. Materials and Methods Please provide the BMI of the respondents Why was the age group 9-14 years selected? Discussion: Please expand the discussion on the possibility of using the test-retest in medicine: in orthopedic and neurological patients, and after the implementation of rehabilitation protocols.

Author Response

REVIEWER 1:

Authors’ Response (AR): Dear Reviewer, we have found your recommendations positive and very constructive. We are grateful for the corrections and the observations that you point out to us.  We have carefully considered all the comments and tried our best to address every one of them.

 

1. Please check the punctuation throughout the text. 

 

Authors’ response (AR): thank you for this suggestion. According to that we have check the whole manuscript and we have modified lines 55, 111, 134, 189, 195, 304 and 326. Moreover, on tables 3, 4 and 5 punctuation has been changed. That is, “coma” has been replaced by “dot”.

 

 

2. Add “...children” in the title. 

 

AR: thank you very much for the detail. The title has been changed: “Test-retest and minimal detectable change in the assessment of muscle strength and muscle power in upper-and lower extremity exercises in 9- to 14-year-olds children.”

 

3. Introduction: line 69-70, please add that it is also important for physiotherapists, patients, parents, and athletes.

 

AR: the sentence has been modified. Please check lines 69-71: “Knowing the repeatability of any strength or muscle power test is important for coaches, doctors, physiotherapists, patients, parents, athletes and scientists for two reasons [33]”

 

4. Materials and Methods Please provide the BMI of the respondents.

AR: according with your suggestion, one column has been added in table 1 to provide BMI.

5. Why was the age group 9-14 years selected? 

AR: this selection students belongs to the second and third stages of compulsory education in Mexico. You can find more information about this topic in the next link: https://www.planyprogramasdestudio.sep.gob.mx/descargables/biblioteca/basica-educ-fisica/III-LA-EDUCACION-BASICA.pdf

 

6. Discussion: Please expand the discussion on the possibility of using the test-retest in medicine: in orthopedic and neurological patients, and after the implementation of rehabilitation protocols.

AR: in accordance with your suggestion, has been added: “With some frequency in clinical studies, the goodness of interventions is established solely on the basis of the presence or absence of statistically significant changes, without taking into account in the interpretation whether the change observed represents a minimally clinical important change for the patient's situation (MCIC), and without assessing whether the magnitude of the changes detected is greater than the random variation subject to the method used, i.e. the MDC. It is easier and more objective to determine the MDC than the MCIC. Therefore, to improve the effectiveness of rehabilitation and physical training interventions it is important, at least, to know the MDC used and to use it for the weighting of Outcome Measures. Keeping the MDC in mind is important for physiotherapists, coaches or sport scientists to determine the efficacy of muscle rehabilitation or strength training programs in children.”. (Lines 392-402)

Author Response File: Author Response.docx

Reviewer 2 Report

General Comments

While this is an interesting topic, the small sample size in each age group is a serious limitation to the quality of this study.  It certainly limits the magnitude of the application of the MDC.

 

Minor Comments:

Page             Line                                                                Comments

     1                  18                “…testing one-repetition maximum tests….” seems redundant.

     1                  19                “…test-retest reliability…”

     1                  20                no need for a comma “….children (-9-14years old) completed two….”

     1                  25                Does this mean “…along the growth curve…”?

     1                  26                Would it be good to include the ICC values for LE and SBP?

     2                  55                “These outcomes….”

     2                  57                “….in daily activities and is associated….”

     2                  72                “…secondly, if the random measurement error….”

     2                  74                “….denoted by minimal detectable change….”

     3                 107              “…criteria included lack of attendance at all …..”

     3                 109              Since you mentioned the grops were divided by age, would it be helpful to have the G9-10, G11-12, and G13-14 descriptions moved to here?

     4                 160              Why provide muscle power for only the 60% 1RM value?

     4                 173              “…both for the LE and SBP was performed…..”

     8                 251              “Therefore, power at 60% of 1RM….”

     9                 276              “Bench press exercise involves powerful…..”

    10                318              “….over the courses of growth and development….”

    10                320              “in the strength of the SBP, the increases only appears….”

    13                452              J. Strength Cond. Res.

    13                455              No pages given for reference 31.

    13                459              Inclusive pages not given for article 34.

    13                462              Inclusive pages not given for article 35.

    13                468              J. Strength Cond. Res. and inclusive pages not given for article 38.

    14                499              Inclusive pages not given for article 51.

Author Response

REVIEWER 2:

Authors’ Response (AR): We appreciate the positive feedback from the reviewer. Moreover, we would like to thank the reviewer for comments and constructive suggestions, which help to improve the quality of the manuscript.

1. While this is an interesting topic, the small sample size in each age group is a serious limitation to the quality of this study.  It certainly limits the magnitude of the application of the MDC.

 AR: we agree with the reviewer. Hence, we showed the results of the total sample group and, moreover, in the last version of the manuscript we have added a new limitation at the last part of the manuscript: “Finally, the sample size was determined to establish the test-retest and the MDC of a global sample of 9 to 14 year-old; the statistical power for the results for each of the age groups is limited by the size of the subsamples” (lines 409-411).

And the conclusions have been modified based on the values of the total sample: “The repeatability of the 1RM test of the SBP was excellent (ICC 0.974) and was better than that of the LE (ICC, 0.954). The MDC of the 1RM test evaluation was 19.56 % in the LE and 12.93% in the SBP”  (lines 26-28)

2. 1-18 “…testing one-repetition maximum tests…” seems redundant.

AR: thank you very much. The word “testing” has been deleted.

3. 1-19 - “…test-retest reliability…”

AR: thank you very much.

4. 1-20 - no need for a comma “…children (-9-14years old) completed two…”

AR: thank you very much. The mistake has been corrected.

5. 1-25 - Does this mean “…along the growth curve…”?

AR: thank you very much. We have added the suggestion made by reviewer.

6. 1-26 - Would it be good to include the ICC values for LE and SBP?

AR: we agree with your comment. ICC values clarify the results of the manuscript.

7. 2-55 - “These outcomes…”

AR: thank you very much. The mistake has been corrected.

8. 2-57 - “…in daily activities and is associated…”

AR: thank you very much. The mistake has been corrected.

9. 2-72 - “…secondly, if the random measurement error…”

AR: thank you very much. The mistake has been corrected.

10. 2-74 - “…denoted by minimal detectable change…”

AR: thank you very much. The mistake has been corrected.

11. 3-107 - “…criteria included lack of attendance at all …”

AR: thank you very much. The mistake has been corrected in line 125.

 

12. 3-109 - Since you mentioned the grops were divided by age, would it be helpful to have the G9-10, G11-12, and G13-14 descriptions moved to here?

AR: thank you very much. We have rephrased this sentencer according with the suggestion made by reviewer. Please, check lines 126 to 130.

“Before the first test was performed, all the school children who agreed to participate were divided into three age groups (G9-10 years, n = 16; G11-12 years; n = 16; and G13-14 years, n = 16) and within each age group were divided by sex (male/female). A number was assigned to each child. To allocate participants to the sample, 4 numbers were randomly chosen from each age and sex (i.e., 4 males 9 years old; 4 females 9 years old, etc.).”

13. 4-160 - Why provide muscle power for only the 60% 1RM value?

AR: To clarify this item, we have added some information in lines 188-190:

“From all the muscle power data, only the muscle power value reached at 60% of 1RM was considered for data analysis since the maximum power was manifested around this load (figure 6).”

14. 4-173 - “…both for the LE and SBP was performed…”

AR: thank you very much. The mistake has been corrected in line 202.

15. 8-251 - “Therefore, power at 60% of 1RM…”

AR: thank you very much. The mistake has been corrected in line 287.

16. 9-276 - “Bench press exercise involves powerful…”

AR: thank you very much. The mistake has been corrected in line 313.

17. 10-318 - “…over the courses of growth and development…”

AR: thank you very much. The mistake has been corrected in line 356.

18. 10-320 - “in the strength of the SBP, the increases only appears…”

AR: thank you very much. The mistake has been corrected in line 358.

19. 13-452 - Strength Cond. Res.

AR: thank you very much. The “S” has been checked (line 533).

20. 13-455 - No pages given for reference 31.

AR: thank you very much. The mistake has been corrected (line 548).

21. 13-459 - Inclusive pages not given for article 34.

AR: this reference does not include pages. Below you will find the e-journal official link for this manuscript:

https://sportsmedicine-open.springeropen.com/articles/10.1186/s40798-020-00260-z#citeas

22. 13-462 - Inclusive pages not given for article 35.

AR: this reference does not include pages. Below you will find the e-journal official link for this manuscript:

https://www.mdpi.com/2227-9032/8/3/285#cite

 

23. 13-468 - Strength Cond. Res. and inclusive pages not given for article 38.

AR: thank you very much. The mistake has been corrected (line 576).

24. 14-499 - Inclusive pages not given for article 51.

AR: thank you very much. The mistake has been corrected in reference 50 (line 605) because reference 46 was duplicated and it has been deleted. Hence, some references have a new number.

 

Author Response File: Author Response.docx