Effects of Functional Fatigue Protocol and Visual Information on Postural Control in Patients with Chronic Ankle Instability

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

The study investigates the effects of a functional fatigue protocol and the availability of visual information on postural control in patients with chronic ankle instability. It was conducted with 28 subjects suffering from chronic ankle instability, assessing their postural control using single-leg balance tests both before and after undergoing the fatigue protocol, with conditions both eyes open and eyes closed. The results indicated significant interactions between fatigue and vision conditions, showing that static postural control ability decreased after the fatigue protocol with eyes open while remaining unchanged with eyes closed. The study suggests that functional fatigue impacts postural control, possibly increasing the risk of ankle sprains during fatigue conditions.

 

The statistical analysis in this paper was comprehensive and methodically structured to address the experimental design and research questions effectively.

 

There are some small issues that need to be addressed before publication:

1.     The y-axis in Figures 2 and 3 is not specified, which could lead to confusion about the data presented.

2.     The description of the single-leg balance test in Section 2.3 lacks sufficient detail to fully understand the experimental setup and procedures.

3.     The reviewer recommends adding appropriate optical images of the experiment to help understanding.

4.     On page 3 line 101, the height should be 166.84±7.45 cm.

Author Response

Thank you for taking the time to review our manuscript. We sincerely appreciate your insightful comments and suggestions, which have greatly contributed to improving the quality of our work.

[Reviewer 1]

The study investigates the effects of a functional fatigue protocol and the availability of visual information on postural control in patients with chronic ankle instability. It was conducted with 28 subjects suffering from chronic ankle instability, assessing their postural control using single-leg balance tests both before and after undergoing the fatigue protocol, with conditions both eyes open and eyes closed. The results indicated significant interactions between fatigue and vision conditions, showing that static postural control ability decreased after the fatigue protocol with eyes open while remaining unchanged with eyes closed. The study suggests that functional fatigue impacts postural control, possibly increasing the risk of ankle sprains during fatigue conditions.

The statistical analysis in this paper was comprehensive and methodically structured to address the experimental design and research questions effectively.

Thank you for taking the time to review our manuscript. We sincerely appreciate your insightful comments and suggestions, which have greatly contributed to improving the quality of our work.

We have addressed each of the comments provided, and we have highlighted them in “light grey” for your convenience.

 

Specific comments that need to be addressed before publication:

1. The y-axis in Figures 2 and 3 is not specified, which could lead to confusion about the data presented.

We agree with the comments and have resolved the issue following the reviewer's suggestion.

2. The description of the single-leg balance test in Section 2.3 lacks sufficient detail to fully understand the experimental setup and procedures.

Thank you for your valuable comment. However, Section 2.4 outlines the set up and procedures for the balance test. We kindly ask for the reviewer's understanding on this matter.

3. The reviewer recommends adding appropriate optical images of the experiment to help understanding.

We agree with you that additional figures will aid the reader's comprehension.

4. On page 3 line 101, the height should be 166.84±7.45 cm.

Thank you for this crucial comment. We have resolved the issue following the reviewer's suggestion

Reviewer 2 Report

Comments and Suggestions for Authors

Overall, the article is interesting and brings important findings regarding factors that influence postural control. More information should be given looking study replication in other populations. Besides of that, manuscript need an English review, in some point grammar mistakes can impair the comprehension.

Details comments follow:

INTRODUCTION

Line 84 cite the full name that represent TTB

METHODS

Design

Mention the study type

Line 93 maybe the expression two independent factors can be better than two independent variables

Participants

Please provided more details of sample size calculation as tested used and alpha, expected power and effect size considered.

Line 221-222 Rewrite the sentence once age and resting heart rate (HR) are not anthropometric data.

Give more information about how foot length, foot width and resting heart rate (HR) were measured.

Any information about participants’ physical activity level was recorded?

Static postural control

Please define successful trial. On average, how many trials did participants perform before three valid trials were recorded?

Please clarify if the teste was performed right after fatigue protocol, or was given some minutes to rest.

HR was measured at begin and end of posttest?

Data analysis

Cite the full name of COP MLi and COP

RESULTS

Line 207 Did you have more than one group? Maybe CAI patients or Individuals with CAI are better expression.

DISCUSSION

Line 241 Same of above comment

Describe studies limitations and future studies.

Clinical Implicativos

Generalizations for athletics populations should be carefully considered, once evaluated samples was not athletics. If so, please give more information in Participants section.

Table 1: IdFAI is not in abbreviations, all acronyms cited should be described in tables.

Table 2: Please double check abbreviations, Rep. time was not cited.

Figure 1 and Figure 3: Add a legend for abbreviations

Table 4: The described results presented in this table do not appear represent ANOVAS outputs, is it correct? All tested carried out should be described in data analysis section.

Author Response

Thank you for taking the time to review our manuscript. We sincerely appreciate your insightful comments and suggestions, which have greatly contributed to improving the quality of our work.

We have addressed each of the comments provided, and we have highlighted them in “sky blue” for your convenience.

 

[Reviewer 2]

Overall, the article is interesting and brings important findings regarding factors that influence postural control. More information should be given looking study replication in other populations. Besides of that, manuscript need an English review, in some point grammar mistakes can impair the comprehension.

Details comments follow:

Thank you for taking the time to review our manuscript. We sincerely appreciate your insightful comments and suggestions, which have greatly contributed to improving the quality of our work.

This paper has been proofread in advance. We have addressed each of the comments provided, and we have highlighted them in “sky blue” for your convenience.

 

INTRODUCTION

Line 84 cite the full name that represent TTB

Thank you for the detailed comment. We cited the full name of TTB.

 

METHODS

Design

Mention the study type

Thank you for your comment. The sentence has been updated in Section 2.1 Design.

 

Line 93 maybe the expression two independent factors can be better than two independent variables

Thank you for your suggestion regarding the terminology. The expression has been updated to ‘independent factors’

 

Participants

Please provided more details of sample size calculation as tested used and alpha, expected power and effect size considered.

We estimated a priori sample size based on previous literature with 80% statistical power, an α level of .05 and an effect size of 0.64.

Line 221-222 Rewrite the sentence once age and resting heart rate (HR) are not anthropometric data.

Thank you for the detailed comment. Age is listed in Table 1, and resting heart rate (HR) has been added in Table 1. according to the comments.

 

Give more information about how foot length, foot width and resting heart rate (HR) were measured.

Thank you for the comment. “Before the warm-up, resting HR was measured using an Apple Watch for one minute Afterward, the Brannock Device was used to measure accurate foot length and width” has been added to the manuscript.

 

Any information about participants’ physical activity level was recorded?

Thank you for your inquiry. However, we did not collect information regarding participants' physical activity levels through a survey or any other means in this study. We did not collect activity levels, but recruited participants who exercise twice a week. “Twenty-eight physically active subjects with CAI (age: 24.07±2.62 years, height: 166.84±7.45 cm, body mass: 61.81±17.09 kg) who exercise more than twice a week were recruited to participate in this study” has been added. We kindly ask for the reviewer's understanding on this matter and have added this point to the limitations section.

 

Static postural control

Please define successful trial. On average, how many trials did participants perform before three valid trials were recorded?

Thank you for your question regarding the successful trials in our study. After a 5-min warm-up on a treadmill at a walking speed of 3 mph, participants underwent two practice trials of the single-leg balance test and the following statement is included in section 2.3 Experimental Procedure.

 

Please clarify if the teste was performed right after fatigue protocol, or was given some minutes to rest.

Thank you for your valuable comment. “The post-fatigue tests were performed immediately after the fatigue protocol upon relocation to the laboratory.” has been added. Additionally, the entire protocol and measurement process took approximately 1 hour and 30 minutes.

 

HR was measured at begin and end of posttest?

Thank you for your question. The induction of submaximal fatigue was achieved through repetitive, rather than acute, efforts. Upon meeting the fatigue criteria based on HR, jump height, and RPE, all participants uniformly proceeded to the laboratory for post-fatigue measurements. Therefore, measurements were not taken at the end. We kindly request the reviewer's understanding regarding this matter.

 

Data analysis

Cite the full name of COP MLi and COP

Thank you for this crucial comment. COP stands for "Center of Pressure," and is located in line 164. To aid in understanding COP MLi, we have included the formula separately.

VCOPMLi=dCOPMLi/.02s

TTBMLi=dMLboundi//VCOPMLi

This formula shows how TTB was calculated based on center of pressure (COP) excursions in the mediolateral direction according to reference 39.

 

RESULTS

Line 207 Did you have more than one group? Maybe CAI patients or Individuals with CAI are better expression.

We agree with you. The expression has been updated to 'CAI Patients

DISCUSSION

Line 241 Same of above comment

Thank you for your valuable comment. The expression has been updated to 'CAI Patients

 

Describe studies limitations and future studies.

We agree with all the comments. Following the reviewer’s suggestion,

“Therefore, this study emphasizes the importance of investigating the effects of balance training under fatigue conditions as a potential approach to mitigate the risk of ankle re-injury and its potential impact on reliance on visual input in CAI patients in future studies.” has been added.

 

Clinical Implications

Generalizations for athletics populations should be carefully considered, once evaluated samples was not athletics. If so, please give more information in Participants section.

Thank you for your comment. We acknowledge the concern about generalizing our findings to the broader athletic population given that our sample may not directly represent competitive athletes. The participants in our study were selected based on their chronic ankle instability (CAI) rather than their athletic status. This distinction is important as it focuses on the specific vulnerabilities and biomechanical behaviors associated with CAI, which might differ from those of elite athletes or those actively engaged in sports competitions. This has been updated in the limitations section.

“Additionally, fatigue-related impairments highlighted in this study are not exclusive to athletes but can also adversely affect individuals with CAI in the physically active population. Fatigue has the potential to compromise postural stability, motor control, and movement strategies, ultimately increasing the risk of injury for those without competitive athletic backgrounds. Thus, understanding fatigue's influence on this vulnerable group is crucial for developing targeted rehabilitation and injury prevention strategies that can benefit a wider spectrum of individuals.’ has been added.

 

Table 1: IdFAI is not in abbreviations, all acronyms cited should be described in tables.

We agree with all the comments and following the reviewer’s suggestion, abbreviations has been added

 

Table 2: Please double check abbreviations, Rep. time was not cited.

Thank you for the comments. We agree with all the comments and following the reviewer’s suggestion, abbreviations has been added

 

Figure 1 and Figure 3: Add a legend for abbreviations

We agree with all the comments and following the reviewer’s suggestion, abbreviations has been added

Table 4: The described results presented in this table do not appear represent ANOVAS outputs, is it correct? All tested carried out should be described in data analysis section.

Thank you for the comments. Table 4. presents the outcomes of paired-sample t-tests conducted at a to discern the variances in visual reliance subsequent to fatigue. The existing content has been moved to before the mention of Cohen's d.