Two Repetitions May Be Enough! Reliability of Movement Timing in Physical Fitness Exercises Performed by Young, Trained Adults Using Inertial Sensors
Round 1
Reviewer 1 Report
Comments and Suggestions for Authors
1. The title should include the population the results / conclusions are relevant for.
2. It is unclear why the authors included male and female subjects and then fail to a) rationalize / develop a hypothesis is the expected results would differ by sex and b analyze the data for males, females, and the combined sample.
3. The experimental design of this study is minimalistic. There is (as mentioned above) no rational given why both sexes were included. But then the authors propose a generic conclusion making readers believe that the conclusions are relevant for any skill / populations of varying ages and skill levels. There is a need to reflect in the title and the conclusions that the repetition number is valid only for certain age, skill, and experience level.
4. The figures lack x and y axis labels.
5. I leave it to the editor to organize the manuscript with respect to the figure. However, I am not convinced that all figures are needed in the body of the manuscript. The manuscript is fragmented by the high number of figures and convey a similar pattern of information.
6. In Table 1, the IMU placement is not described accurately. For example, anatomically there is no information in such position description as ‘chest’.
Author Response
Reviewer 1 Comment 1: The title should include the population the results / conclusions are relevant for.
Authors’ Response: The title has been revised.
Reviewer 1 Comment 2: It is unclear why the authors included male and female subjects and then fail to a) rationalize / develop a hypothesis is the expected results would differ by sex and b analyze the data for males, females, and the combined sample.
Authors’ Response:
Initially, the analyses were conducted separately for men's and women's groups. However, upon observing consistent behavior in reliability indices between the two genders, we proceeded with a combined group analysis.
Reviewer 1 Comment 3: The experimental design of this study is minimalistic. There is (as mentioned above) no rational given why both sexes were included. But then the authors propose a generic conclusion making readers believe that the conclusions are relevant for any skill / populations of varying ages and skill levels. There is a need to reflect in the title and the conclusions that the repetition number is valid only for certain age, skill, and experience level.
Authors’ Response: This comment is similar to Comment 1. We realize the reviewer’s point of view and the title has been revised to include the population = Young Trained Adults. However, we consider that the title is already long enough to also include information about skill and experience level, elements that the reader inevitably will find in the Methods and that were clearly stated already in the initial submission. Furthermore, in conclusion, we have made it explicit that our findings are relevant to the studied population of young, trained adults.
Reviewer 1 Comment 4: The figures lack x and y axis labels.
Authors’ Response: We apologize for this issue. As the figures are already too busy, we chose to place the labels in a non-typical position, that is on the top of each figure. However, we realize the reviewer’s point of view, thus, typical X and Y axis labels have been added in all Figures.
Reviewer 1 Comment 5: I leave it to the editor to organize the manuscript with respect to the figure. However, I am not convinced that all figures are needed in the body of the manuscript. The manuscript is fragmented by the high number of figures and convey a similar pattern of information.
Authors’ Response: We realize the Reviewer’s point, and this was actually our concern. We kept some basic figures in the body of the manuscript and we provided all others in an Appendix.
Reviewer 1 Comment 6: In Table 1, the IMU placement is not described accurately. For example, anatomically there is no information in such position description as ‘chest’.
Authors’ Response: Table 1 has been deleted. Figure information is in Appendix A- Figure 1. The term 'chest' has been replaced with the more precise term 'upper trunk' for body segment and 'manubrium' for IMU placement.
Author Response File: 
Author Response.pdf
Reviewer 2 Report
Comments and Suggestions for Authors
Brief summary
The paper aims to assess the minimum number of repetitions that is needed to achieve high reliability of temporal measures from inertial sensor data for different functional movements. The main contribution of the paper is the finding that just two repetitions of a single trial achieved excellent intra- and inter-trial reliability. In addition, including three trials with four repetitions per trial, enhanced the reliability across all exercises. Strengths of the article include the extensive statistical analysis that took place to analyse the temporal reliability of inertially sensed functional movements. The experimental protocol was sound and appropriate for the research objective stated in the introduction. The overall structure of the article is mostly clear, but certain paragraphs in the manuscript are hard to read which makes following the structure difficult at times.
General concept comments
Introduction
Regarding the research objective. The research gap is clear and sufficient references are given in the introduction leading to the research question. But some terms are not defined or explained as soon as they are stated which makes it difficult to fully comprehend the research question, see specific comments for more information.
Methods
The description of the participants which were involved is clear and complete. In the experimental procedure description paragraph some aspects need clarification (cf. specific comments). Overall, the described experimental procedure and statistical analysis is sound for answering the proposed research question. However, there are some aspects missing in the description (cf. specific comments).
The description of the reliability indices is confusing as there are some duplications in the definition which lead to the paragraph not being consistent (cf. specific comments). Overall, the amount of reliability indices makes it partially hard to follow the argumentation of the paper, because there is an overwhelming amount of information that has to be processed and comprehended.
The cut-off frequency of the Butterworth filter is quite small. As a standard, a cut-off frequency of 6 Hz is chosen for biomechanical analyses. It is questionable whether it does not affect the results and the conclusion of your argument too much, as the movement is very smoothed out by the filter. This can also be seen in the example curves in Figure 1.
Results
The paragraph describing the number of required repetitions and trials seems kind of vague. First, it is stated that one trial and two repetitions is enough to achieve excellent reliability. In the next sentence, potential exceptions are listed. The potential exceptions include three of the eight investigated movements, which amounts to 37.5%. This percentage is more than just an exception and thus the conclusion is not consistent to the evidence (cf. specific comments).
Specific comments
Introduction:
· Line 62: A clear definition for the term ‘temporal reliability’ is missing. As this term is essential for comprehending the research question and following results, it should be defined or explained at the first mention.
· Line 66: The same goes for the term ‘temporal measures’. What exactly is meant? This should be explained in more detail at an earlier stage of the introduction.
Methods
· Is there some kind of explanation/ reference that a 2-minute rest time is enough so to not induce fatigue between the different trials and exercises?
· Line 88-89: Were the movement executions of the participants evaluated beforehand to ensure that the proper technique was executed?
· Line 92: How many sensors were used?
· Line 96-97: But that only applies for specific axes of the IMU coordinate systems. The axis of rotation which was analysed for every IMU is stated in table 1. It should already be made clear in line 96 that this statement does not apply to all axes of every IMU.
· Line 101: Why was that body segment then deemed the most representative? Because that body segment experiences the largest range of motion? An explanation or argumentation is missing here.
· Line 104: The chosen cut-off frequency is quite small. As a result, the data is smoothed quite much through the filter. As a standard, a cut-off frequency of 6 Hz is used for filtering human motion data. This should at least be mentioned in the discussion, as a small cut-off frequency could lead to better reliability results because of the level of smoothing that is applied to the data.
· Table1: Which leg was the standing leg during the lunge? That information is important for understanding the angular velocity curves shown in Figure 1.
· Table1: Without showing or describing the coordinate systems, stating the axis of rotation does not make sense. In which coordinate system are the axes defined? In a global body coordinate system or is each axis of rotation expressed in the associated IMU coordinate system?
· Line 116: The formulation of the second half of the sentence regarding the absolute durations of both phases is confusing. As it is, it sounds like the same duration is meant as the cycle duration. Reformulating that sentence would make it clearer and easier to understand.
· Line 147: What does relative reliability mean exactly? That term should be defined.
· Line 154: Same as the comment above. What exactly is absolute reliability?
· Line 156: How is this ‘variable’ then called in the paper? It cannot just be called SEM when you express the SEM as a percentage of the mean as it is written.
· Line 159: How does this differ to the explanation in line 156? Please make that clear, because it makes it hard to understand the aspect ‘SEM%’ like this. Maybe during editing the explanation in this line has been added and the statement in line 156 has not been removed?
· Line 167: The equation should probably be written: MDC95 = SEM x 1.96 x sqrt(2). The way the equation is stated does not make sense as it equates the two values MDC95 and SEM, even though these are two completely different aspects.
· Line 170: Are there established reference values for temporal parameters in general? Or are the reliability indices which you describe here the established reference values for temporal parameters? If yes, then this should be clearly stated.
Results:
· Line 189: Is it an exception or not? The wording is very vague and not appropriate for the result section.
· Line 190: Same as before, they either do or do not require more repetitions than other movement tasks. And the required repetition values that are stated all exceed the value 2.
· Line 205-206: Is the data from which this conclusion has been drawn, so the CV% values for all variation, somewhere stated, e.g. in the Appendix? If yes this should be stated here.
Discussion:
· Line 330-331: Is this not data that can be taken from the technical data sheet of the sensors? If the measurement error is quantified, then the influence of the measurement error on the reliability could be estimated.
· Line 334-335: But then what about human variability? How does that compare (in size) to the measurement reliability? Can high reliability even be achieved if there is always human variability in motion data?
· Line 353: Can this be concluded from the data? If yes, from which values?
· Line 386: Incorrect citation format.
· Line 397: That are three out of eight movements (37%). This should be in some way further discussed/ mentioned, as for more than a third of the movements, more than two repetitions are needed for high reliability.
· Line 399-400: Doesn’t this statement contradict with the statement in line 385-386? In those lines it is stated that 10 cycles are recommended.
· Line 401: What do they then use?
· Line 432: An example for another exercise or activity would be beneficial here.
References
· Line 540: Information is missing from citation. What about publisher, publisher location (city and country)?
Figures:
· Figure 1: It is quite confusing that the direction of the sine curves for the lunge and squat motion differs. I suppose this happens, because the specific coordinate axes point in different directions. So, the coordinate systems are not really consistent which makes it difficult to read and comprehend the figure. Maybe a sentence explaining that this can happen, because the coordinate system does not always point in the same direction would help to clear that up.
· Figure 2: Axes labels are missing and should be added.
· Figure 2: The quality of the figure is not good. If possible, it should be enhanced e.g. by exporting the figure with a higher dpi value.
· Figure 2: What about T1-T3 and T2-T3? Is there a reason why that was not analysed? Or would that just be redundant and was left out because of that?
· Figure 3: Which motion does the first row of results describe? Probably the two leg hop, but the title is missing and should be added.
· Figure 2-7: The figures are 6 pages long in summary. Reading the results section feels overwhelming because of that. Is there a possibility to lower the number of plots? Or would it be possible to select only the most important results and put some other results into the Appendix?
Author Response
Specific comments
Introduction: = 2Comments
Reviewer 2 Comment 1: Line 62: A clear definition for the term ‘temporal reliability’ is missing. As this term is essential for comprehending the research question and following results, it should be defined or explained at the first mention.
Authors’ Response: It is now explained in the introduction 4tht paragraph, lines 56-59 in the revised manuscript: The repetitions within a single trial or the trials within the same session constitute measures applied at different time points to the same subjects and their stability over time defines their temporal reliability [18]. The equivalence of items from the same test (i.e., the different temporal measures used to evaluate the timing of a movement when a motor task is evaluated) represent the internal consistency of temporal reliability [18].
Reviewer 2 Comment 2: Line 66: The same goes for the term ‘temporal measures. What exactly is meant? This should be explained in more detail at an earlier stage of the introduction.
Authors’ Response: It is now explained in the introduction 1st paragraph, lines 31-34 in the revised manuscript:
Temporal analysis aims to the movement timing using variables such as the duration of the whole cycle of movement and the duration of the movement phases (the latter expressed in seconds as well as a percentage of the cycle of movement duration).
Methods = 17 Comments
Reviewer 2 Comment 3: Is there some kind of explanation/ reference that a 2-minute rest time is enough so to not induce fatigue between the different trials and exercises?
Authors’ Response: Reference added: Grgic, J., Schoenfeld, B.J., Skrepnik, M. et al. Effects of Rest Interval Duration in Resistance Training on Measures of Muscular Strength: A Systematic Review. Sports Med 48, 137–151 (2018). https://doi.org/10.1007/s40279-017-0788-x
Reviewer 2 Comment 4: Line 88-89: Were the movement executions of the participants evaluated beforehand to ensure that the proper technique was executed?
Authors’ Response: There was an inclusion session where all participants were evaluated. However, they were all experienced.
Reviewer 2 Comment 5: Line 92: How many sensors were used?
Authors’ Response: A total of six (6) sensors were used (head, forearm, upper trunk, lower trunk, shank, thigh) but only one sensor was used for each exercise, that is the one for the segment that experienced the largest range of motion for each specific exercise (Figure 1 and Appendix B-Figure 1).
Reviewer 2 Comment 6: Line 96-97: But that only applies for specific axes of the IMU coordinate systems. The axis of rotation which was analysed for every IMU is stated in table 1. It should already be made clear in line 96 that this statement does not apply to all axes of every IMU.
Authors’ Response: A clarification was made in the revised text, lines113-118: for each exercise, the segment associated with the greatest range of motion at the movement’s plane of motion was selected for further analysis as it provided the most representative angular velocity trajectory (Figure 1). These angular velocity trajectories demonstrated a clear periodic waveform (sine wave) consisting of two regions, one of positive and one of negative angular velocity, corresponding to the two basic phases of each motion pattern.
Reviewer 2 Comment 7: Line 101: Why was that body segment then deemed the most representative? Because that body segment experiences the largest range of motion? An explanation or argumentation is missing here.
Authors’ Response: It is now explained in the method, lines 11-115: A total of 6 sensors were placed on the participant’s body; however, only one sensor was used for each movement evaluation (Appendix A-Figure 2). In specific, for each exercise, the segment associated with the greatest range of motion at the movement’s plane of motion was selected for further analysis as it provided the most representative angular velocity trajectory (Figure 1).
Reviewer 2 Comment 8: Line 104: The chosen cut-off frequency is quite small. As a result, the data is smoothed quite much through the filter. As a standard, a cut-off frequency of 6 Hz is used for filtering human motion data. This should at least be mentioned in the discussion, as a small cut-off frequency could lead to better reliability results because of the level of smoothing that is applied to the data.
Authors’ Response: This information has been added in the revised text and the mentioned figure is in Appendix B: The 2Hz cut-off frequency was chosen after examining the frequency power spectrum of all signals (Appendix B– Figure 1) that clearly indicated the highest signal intensity at 2Hz in all movements.
Reviewer 2 Comment 9: Table1: Which leg was the standing leg during the lunge? That information is important for understanding the angular velocity curves shown in Figure 1.
Authors’ Response: This information has been added in the revised text, line 97: forward lunge (right foot forward step in all participants)
Reviewer 2 Comment 10: Table1: Without showing or describing the coordinate systems, stating the axis of rotation does not make sense. In which coordinate system are the axes defined? In a global body coordinate system or is each axis of rotation expressed in the associated IMU coordinate system?
Authors’ Response: We realize the reviewer’s point of view. Indeed, there is no meaning without the reference coordinate system. All information about the sensor placement on the body is included in Figure 1 and in Appendix A-Figure 2, together with the photo sequence of the movement. The movement’s plane of motion where angular velocity was evaluated is mentioned.
Reviewer 2 Comment 11: Line 116: The formulation of the second half of the sentence regarding the absolute durations of both phases is confusing. As it is, it sounds like the same duration is meant as the cycle duration. Reformulating that sentence would make it clearer and easier to understand.
Authors’ Response: An overall reformulation has been made in Methods 2.2.2 Temporal Variables, Methods 2.3. Statistical analysis. And also concerning the whole Results section, to facilitate reading and comprehension to follow the reviewers’ overall suggestions in this issue.
Reviewer 2 Comment 12 : Line 147: What does relative reliability mean exactly? That term should be defined.
Authors’ Response: The term definition has been added in 2.3. Statistical Analysis, Paragraph 2.3.1. Relative reliability: Relative reliability refers to the magnitude of the association of repeated measurements by quantifying the correlation among them. It forms the ratio of total variability (between subjects) and individual variability (within subject) which produces the ICC [23,27].
Reviewer 2 Comment 13: Line 154: Same as the comment above. What exactly is absolute reliability?
Authors’ Response: The term definition has been added in 2.3. Statistical Analysis, Paragraph 2.3.2. Absolute reliability: Absolute reliability refers to the within subject variability and it is not sample-dependent because the range of individual scores is not accounted [23,27].
Reviewer 2 Comment 14: Line 156: How is this ‘variable’ then called in the paper? It cannot just be called SEM when you express the SEM as a percentage of the mean as it is written.
Authors’ Response: We apologize for the mistake; it has been corrected. Please, see, Statistics, 2.3.2 Absolute reliability
Reviewer 2 Comment 15: Line 159: How does this differ to the explanation in line 156? Please make that clear, because it makes it hard to understand the aspect ‘SEM%’ like this. Maybe during editing the explanation in this line has been added and the statement in line 156 has not been removed?
Authors’ Response: We apologize for the mistake; it has been corrected. Please, see, Statistics, 2.3.2 Absolute reliability
Reviewer 2 Comment 16: Line 167: The equation should probably be written: MDC95 = SEM x 1.96 x sqrt(2). The way the equation is stated does not make sense as it equates the two values MDC95 and SEM, even though these are two completely different aspects.
Authors’ Response: We apologize for the mistake; it has been corrected. Please, see, Statistics, 2.3.2 Absolute reliability
Reviewer 2 Comment 17: Line 170: Are there established reference values for temporal parameters in general? Or are the reliability indices which you describe here the established reference values for temporal parameters? If yes, then this should be clearly stated.
Authors’ Response: The sentence has been removed from the statistics section and is discussed in the discussion Section.
Results: = 3 Comments
Reviewer 2 Comment 18: Line 189: Is it an exception or not? The wording is very vague and not appropriate for the result section.
Authors’ Response: We apologize for the vagueness. The whole results section has been reformulated to improve the clarity of results’ presentation.
Reviewer 2 Comment 19: Line 190: Same as before, they either do or do not require more repetitions than other movement tasks. And the required repetition values that are stated all exceed the value 2.
Authors’ Response: We totally realize the reviewer’s comment. We mislead the reader due the emphasis on the ICC index which indeed indicates more than 2 repetitions in specific exercises while the other two reliability indices do indicate 2 repetitions as enough. This mistake of ours has been restored through the reformulation of the Results Section and also through adding the number of repetitions required for the SEM% and the MDC95% in the Tables provided in Appendix C.
Reviewer 2 Comment 20: Line 205-206: Is the data from which this conclusion has been drawn, so the CV% values for all variation, somewhere stated, e.g. in the Appendix? If yes this should be stated here.
Authors’ Response: We apologize for this mistake. The CV% results are now included in Figure 5, Appendix B Figure 4, Appendix C Table 1 and Table 2
Discussion: = 8 Comments
Reviewer 2 Comment 20: Line 330-331: Is this not data that can be taken from the technical data sheet of the sensors? If the measurement error is quantified, then the influence of the measurement error on the reliability could be estimated.
Authors’ Response: The reviewer’s comment is not clear to us. We report the standard error of measurement. If the reviewer wants to provide specific details, we would be glad to try on this point.
Reviewer 2 Comment 21: Line 334-335: But then what about human variability? How does that compare (in size) to the measurement reliability? Can high reliability even be achieved if there is always human variability in motion data?
Authors’ Response: To the best of our understanding, the reviewer’s concern may be due to the absence of CV% data. The CV% results are now included in Figure 5, Appendix B Figure 4, Appendix C Table 1 and Table 2
Reviewer 2 Comment 22: Line 353: Can this be concluded from the data? If yes, from which values?
Authors’ Response: Yes, this conclusion can be inferred from the data, particularly by examining the coefficient of variation (CV%) values across the movement durations, both expressed in second and as tcycle.
Reviewer 2 Comment 23: Line 386: Incorrect citation format.
Authors’ Response: Corrected = 28
Reviewer 2 Comment 24: Line 397: That are three out of eight movements (37%). This should be in some way further discussed/ mentioned, as for more than a third of the movements, more than two repetitions are needed for high reliability.
Authors’ Response: We totally realize the reviewer’s comment. We mislead the reader due the emphasis on the ICC index which indeed indicates more than 2 repetitions in specific exercises while the other two reliability indices do indicate 2 repetitions as enough. However, even only with the ICC results the discrepancy does not concern the 37% of the exercises because the need for more repetitions yields only in temporal measures expressed as a percentage of tycle. All measures expressed in seconds yield 2 repetitions as adequate for excellent reliability in all indices (ICC, SEM% and SEM95%). This misleading presentation of results on our behalf has been restored through the reformulation of the Results Section and also through adding the number of repetitions required for the SEM% and the MDC95% in the Tables provided in Appendix A.
Reviewer 2 Comment 25: Line 399-400: Doesn’t this statement contradict with the statement in line 385-386? In those lines it is stated that 10 cycles are recommended.
Authors’ Response:Same response as in Comment 24.
Reviewer 2 Comment 26: Line 401: What do they then use?
Authors’ Response: The following information has been added: Hammil and McNiver [9] used running ground reaction force data recorded with a force plate, while Oliveira and Pirscoveanu [17] also used running ground reaction force recorded with a force plate as well as optical motion data recorded with an 8-camera system. Kribus-Shmiel and coworkers [28] recorded their gait data with a motion capture system as well as with a inertial sensor based system that served for detecting the heel strike event.
Reviewer 2 Comment 27: Line 432: An example for another exercise or activity would be beneficial here.
Authors’ Response: The following information has been added:as for example shown by the higher number of movement cycles necessitated in gait studies (i.e. 23–25 strides, [28]).
References = 1 Comment
Reviewer 2 Comment 28: Line 540: Information is missing from citation. What about publisher, publisher location (city and country)?
Authors’ Response: Has been corrected and formatted to [21] Fleiss, J.L. The Design and Analysis of Clinical Experiments; Willey: New York, USA; 1986.
Figures: 6 Comments
Reviewer 2 Comment 29:Figure 1: It is quite confusing that the direction of the sine curves for the lunge and squat motion differs. I suppose this happens, because the specific coordinate axes point in different directions. So, the coordinate systems are not really consistent which makes it difficult to read and comprehend the figure. Maybe a sentence explaining that this can happen, because the coordinate system does not always point in the same direction would help to clear that up.
Authors’ Response: The figure has been revised for clarity.
Reviewer 2 Comment 30Figure 2: Axes labels are missing and should be added.
Authors’ Response: The X and Y axis labels have been added in all Figures. We apologize for the omission.
Reviewer 2 Comment 31: Figure 2: The quality of the figure is not good. If possible, it should be enhanced e.g. by exporting the figure with a higher dpi value.
Authors’ Response: Figure is now revised and provided in enhanced quality.
Reviewer 2 Comment 32: Figure 2: What about T1-T3 and T2-T3? Is there a reason why that was not analysed? Or would that just be redundant and was left out because of that?
Authors’ Response: All figures have been revised/correction for clarity; however, we are afraid we do not realize the reviewer’s point in this comment.
T1-T2-T3 are abbreviations for Trial 1, Trial2 and Trial 3, and the analysis has been stated (both in Methods as well as in the Figure’s Legend, as ====intra-trial reliability (each trial separately: T1, T2, T3) and inter-trial reliability (2 and 3 trials’ average: T1-T2, T1-T2-T3, respectively)
Reviewer 2 Comment 33: Figure 3: Which motion does the first row of results describe? Probably the two-leg hop, but the title is missing and should be added.
Authors’ Response: We apologize for the negligence. Indeed, it is the two-leg hop, the mistake has been corrected in the revised figure.
Reviewer 2 Comment 34:Figure 2-7: The figures are 6 pages long in summary. Reading the results section feels overwhelming because of that. Is there a possibility to lower the number of plots? Or would it be possible to select only the most important results and put some other results into the Appendix?
Authors’ Response: All three figures concerning the temporal measures expressed in tcycle (Figure 3, 5 and 7 in the initial submission) have been moved to the Appendix B.
Author Response File: Author Response.pdf
Round 2
Reviewer 2 Report
Comments and Suggestions for Authors
Brief summary
The paper aims to assess the minimum number of repetitions that is needed to achieve high reliability of temporal measures from inertial sensor data for different functional movements. The main contribution of the paper is the finding that just two repetitions of a single trial achieved excellent intra- and inter-trial reliability. In addition, including three trials with four repetitions per trial, enhanced the reliability across all exercises. Strengths of the article include the extensive statistical analysis that took place to analyse the temporal reliability of inertially sensed functional movements. The experimental protocol was sound and appropriate for the research objective stated in the introduction. After the revision, the overall structure of the article is clear. Revisions in the methods and results sections improved the quality of the paper.
General concept comments
Introduction
All specific comments have been dealt with appropriately. Missing definitions have been added.
Methods
All specific comments except for one (see specific comments) have been dealt with appropriately. Missing aspects have been added (numbers of sensors used, selection of most representative segment, orientation of IMU coordinate systems).
Explanations for the terms relative and absolute reliability have been added. Duplications have been removed and reliability indices are now defined correctly. All revisions in this section result in a manuscript text that is much easier to read and in turn makes it easier to follow the argumentation of the article.
An explanation for the chosen cut-off frequency of the Butterworth filter was missing in the previous version. A reasonable explanation has now been added.
Results
The reformulation of the results section improved the clarity of presented results. Previous vague formulations have been resolved.
Discussion
All specific comments have been dealt with accordingly.
References
Missing information from citation has been added.
Figures:
The overall quality of the figures was enhanced. Some figures have been moved to the Appendix which additionally improves the reading flow. Missing figure aspects (axes labels, title) have been added.
Specific comments
Methods
Line 99: A reference has been added to the statement, but it is not clear what this reference refers to. I suppose it states that a 2-minute rest time is enough to avoid inducing fatigue between trials, but this is not stated in the sentence. An addition of such a statement is necessary for the reference.
Results:
Line 271-272: MDC95% was well above the upper boundary limit of the SEM%. I am missing an explanation at some point, what this means or why this is reported. Without this explanation it is also difficult to understand figure 6.
Figures:
Figure 6: See comment above. I had quite some trouble with understanding what this figure exactly shows. A short explanation of the meaning of an MDC95% value above the upper boundary limit of the SEM% at some point in the manuscript would surely help to make it easier to understand.
Author Response
Reviewer 2 Comment 1:
Line 99: A reference has been added to the statement, but it is not clear what this reference refers to. I suppose it states that a 2-minute rest time is enough to avoid inducing fatigue between trials, but this is not stated in the sentence. An addition of such a statement is necessary for the reference.
Authors’ Response:
We have revised the sentence to explicitly state that the 2-minute rest time was implemented to avoid inducing fatigue between trials.
Reviewer 2 Comment 2
Line 271-272: MDC95% was well above the upper boundary limit of the SEM%. I am missing an explanation at some point, what this means or why this is reported. Without this explanation it is also difficult to understand figure 6.
Authors’ Response:
In lines 204-206 we incorporated an explanation about the significance of an MDC95% value surpassing the upper boundary limit of the SEM%. Specifically, the following sentence was included: 'An MDC95% value above the upper boundary limit of the SEM% suggests that changes or differences in the measured parameter are greater than what could be attributed to random measurement error.' This addition aims to clarify the implications of observing such values and facilitate the interpretation of Figure 6.
Also, the same sentence has been added in the legend of Figure 6
