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. 2025 Sep 8;20(9):e0331553. doi: 10.1371/journal.pone.0331553

Sex as a moderator of the relationship between hip abduction strength and muscle activation during single-leg stance

Rodrigo Rodrigues 1,2,3, Francesca Chaida Sonda 3, Michele Fernandes Frigotto 4, Pablo Gaviraghi 4, Talita Molinari 2, Nicolas da Silva Pereira 2, Matheus Iglesias Marques 1,2, Rodrigo Freire Guimarães 1,2, Eduarda Bastos Cabral 1,2, Rodrigo Rabello 5,*
Editor: Valentina Graci,6
PMCID: PMC12416692  PMID: 40920685

Abstract

Background

Single-leg stance requires pelvic stability, largely supported by the hip abductors. Differences in hip abductor activation between sexes and individuals with or without musculoskeletal conditions may relate to abductor weakness. However, the relationship between hip abduction strength and muscle activation during stance, and whether this is moderated by sex, remains unclear.

Objective

To investigate whether maximal hip abduction strength is associated with hip abductor EMG amplitude during single-leg stance, considering sex as a moderator.

Methods

Thirty-six adults (18 males, 18 females) performed an estimated 1RM side-lying hip abduction test and two 10-second single-leg stance trials. EMG amplitude of the gluteus medius (GMed) and tensor fasciae latae (TFL) was analyzed. A moderation analysis (PROCESS Model 1) was used to test the interaction between strength and sex.

Results

Hip abduction strength, sex, and their interaction explained 51% of the variance in GMed EMG amplitude (R2 = 0.51; p < 0.001). A significant strength × sex interaction were observed (p = 0.002). Females with lower strength showed greater GMed activation (p < 0.001); this was not seen in males (p = 0.24). No significant effects were found for TFL activation (R2 = 0.02; p = 0.89).

Conclusion

Females with lower hip abduction strength demonstrate greater GMed activation during single-leg stance, suggesting a sex-specific compensatory strategy. No similar effect was observed for TFL. These findings highlight the importance of considering sex in neuromuscular assessments of pelvic stability.

Introduction

During various motor tasks, such as gait or single-leg squat, single-leg stance positions are required [1]. In addition to other muscle synergies, this position involves a maintenance of pelvis frontal plane alignment, which is a specific role of gluteus medius (GMed) [2]. Thus, differences in the muscle activation of GMed have been reported between people with and without low back [3] and knee pain [4–6]. The primary reason for differences in EMG amplitude is attributed to hip abductor weakness [3,7,8]. This concept may support two contrasting ideas: (i) when the muscles are weak, their activation is also lower as they compensate this hip abductor weakness by increasing ipsilateral trunk lean [4,9]; (ii) when the muscles are weak, their activation is higher as a possible compensatory effect to maintain pelvis alignment [7,10]. Moreover, other compensatory strategy could be increasing the activation of synergists, such as the tensor fascia lata (TFL), an important hip abductor when the hip is extended [2]. In fact, it is possible that this is a cyclic mechanism whereby the muscles are initially weak due to this inability to activate the muscle across activities. If either of these ideas are true, we would expect to find an association between strength level and EMG amplitude during single-leg tasks.

Sex is a potential moderator, given that similar explanations have been reported in male–female comparisons [4,8]. Historically, females have been underrepresented in physiological studies, with findings from male samples often being generalized to females [11]. This is a significant issue, as there are several biological differences in females that are not considered and may provide advantages to females in sustained tasks [12]. Moreover, there is a growing body of research in exercise science that considers sex differences, driven by the increasing participation of females in various sports [13], but with higher rates of some injuries [3,4,14]. One emerging aspect is the understanding of how neuromuscular control strategies are achieved [15], which appear to differ between sexes [16,17] and may also be reflected in EMG amplitude. Our study aims to examine whether there is an association between maximal strength and EMG amplitude of the GMed and TFL during single-leg stance, with sex as a potential moderator of this relationship.

Methods

Participants

Males and females were recruited at university campus. Eligible participants had no history of lower limb injuries and participated in strength training programs for at least three months at the time of data collection. The study was conducted in accordance with the principles of the Declaration of Helsinki, and all participants provided written consent after receiving a thorough explanation of the procedures involved. This study was approved by the university’s ethics committee (n: 3.446.338).

Procedures

All assessments were completed within a single visit, following a predetermined sequence: (i) evaluation of body composition parameters and training history; (ii) assessment of hip abductors Maximal Isometric Voluntary Contraction (MIVC); (iii) single-leg stance task; (iv) estimation of 1RM for the side-lying hip abduction exercise.

Hip abductors maximal voluntary isometric contractions.

After 15 submaximal repetitions of side-lying hip abduction for warm-up, 3 MVIC were performed with the hip of the dominant side abducted at a 10º angle, while recording the EMG signal of the GMed and TFL. The contralateral leg was flexed at both the hip and knee to 90º. To ensure standardized resistance, the distal region of the dominant leg (approximately 5 cm above the lateral malleolus) was securely positioned against a rigid and fixed structure [8].

Single-leg stance.

Participants performed two 10-second single-leg stance tasks with 30 seconds of rest between attempts [18]. The test was performed barefoot on a firm surface, with participants’ arms crossed over their shoulders, eyes open, and the contralateral knee flexed. If the participant lost balance and touched the floor with the other foot, the attempt was considered invalid and had to be repeated. The mean of the two valid attempts was used for analysis.

EMG data acquisition and analysis.

An electromyographer with a sampling rate of 2000 Hz and 14-bit resolution (Miotool-400, Miotec – Biomedical Equipment, Porto Alegre, Brazil) was used to capture the activation of the GMed and TFL during MVIC and single-leg stance tasks. After skin preparation, two electrodes with a radius of 15 mm (Kendall Mini MediTrace 100 – Tyco Healthcare, São Paulo, SP, Brazil) were placed 20 mm apart (center-to-center) on the skin over each muscle belly, following the guidelines outlined by SENIAM.

EMG data were filtered using a 4th order Butterworth filter (bandpass: 20–500 Hz), rectified and smoothed using a low-pass 6 Hz Butterworth filter. The highest RMS value of GMed and TFL obtained during the five-second period of MVIC was recorded as the maximal activation. During the single-leg stance task, the RMS average activation was computed and normalized by MVIC of the respective muscles (expressed as a percentage of maximal activation). All EMG data analysis were conducted using a custom-written MATLAB script (vR2021b, Mathworks Inc., Natwick, WY, United States).

1RM test.

To estimate 1RM, the weight used was multiplied by the Lombardi coefficients according to the number of repetitions performed (up to a maximum of 10), and the resulting value was calculated. The test consisted of side-lying hip abduction exercises, initially performed with ankle weights corresponding to 20% of each participant’s body weight. Execution speed was controlled using a metronome set at 60 beats per minute, with two beats allocated for each phase of the movement. If participants completed more than 10 repetitions with the initial load, a three-minute rest was provided, and the load was increased by 10% for a new attempt [17]. Both absolute load (expressed in kg) and relative load (normalized to body mass and expressed in kg/kg) were included in the analysis.

Statistical analysis

The assumptions of linear regression were first verified. Residual normality was assessed through histogram and normal probability plot, homoscedasticity was evaluated using standardized residual plots, and multicollinearity was examined using tolerance and variance inflation factor values. Subsequently, outlier detection was conducted using standardized residuals, leverage values, and Cook’s distance to identify influential cases. No extreme outliers were detected that warranted exclusion, and all data points were retained for analysis.

To test whether sex moderated the relationship between hip abduction strength and muscle activation, a moderation analysis was conducted using the PROCESS macro, model 1 (version 4.0), which is an open-source package used for moderation analysis [19]. Hip abduction strength (1-RM absolute and relative to body mass) was entered as the independent variable in separate analysis, EMG amplitude (either GMed or TFL) as the dependent variable, and sex (coded as 1 = male, 2 = female) as the moderator. The interaction term (strength × sex) was computed automatically by PROCESS. Statistical significance was set at p < 0.05. The Bonferroni correction was used, adjusting the significance threshold by dividing the alpha level (0.05) by the number of main tests conducted (four). Thus, results were considered statistically significant at an adjusted alpha level of 0.0125. The proportion of explained variance (R2) and changes in R2 due to the interaction were reported. Conditional effects of strength on EMG amplitude were examined separately for each sex when the interaction was significant. All statistical analyses were performed using SPSS 22.0 software (SPSS Inc., Chicago, USA).

Results

Eighteen males (age: 26.4 ± 3.9 years; body mass: 84.7 ± 10.9 kg; height: 1.76 ± 0.04 m; resistance training experience: 78% over 12 months; absolute 1RM: 18.7 ± 3.1 kg; relative 1RM: 0.22 ± 0.03 kg/kg) and 18 females (age: 26.1 ± 4.8 years; body mass: 60.1 ± 8.4 kg; height: 1.62 ± 0.09 m; resistance training experience: 78% over 12 months; 78% using hormonal contraception; absolute 1RM: 12.3 ± 2.2 kg; relative 1RM: 0.20 ± 0.04 kg/kg) were evaluated.

In the absolute 1RM, for GMed, the overall model was statistically significant [F(3, 32) = 11.10, p < 0.001, explaining approximately 51% of the variance in EMG amplitude (R² = 0.51). There was a significant interaction between hip strength and sex (β = −1.86, t(32) = −3.45, p = 0.002, 95% CI = −2.9; −0.76). Conditional analyses revealed a significant effect of hip strength on EMG amplitude for females (β = −2.24, p < 0.001, 95% CI = −3.1; −1.3), but not for males (β = −0.37, p = 0.247, 95% CI = −1; 0.27), suggesting that lower strength was associated with greater activation only among females (Fig 1).

Fig 1. Relationship between 1RM and EMG amplitude of GMed e TFL during single-leg stance.

Fig 1

Open in a new tab

Each point represents one participant. Solid red circles correspond to females, and blue circles represent males. Lines indicate the linear regression for each group, with shaded areas representing the 95% CI.

For TFL, the overall model was not statistically significant [F(3, 32) = 0.19, p = 0.89], explaining only 2% of the variance in EMG amplitude (R2 = 0.02). There was no significant interaction between hip strength and sex (β = −0.16, t(32) = −0.15, p = 0.88, 95% CI = −2.3; 1.99), nor a significant main effect of absolute hip strength (β = 0.59, t(32) = 0.39, p = 0.70, 95% CI [−2.48, 3.60]) or sex (β = 5.11, t(32) = 0.32, p = 0.75, 95% CI [−27.50, 37.80]) (Fig 1).

When the analysis was performed with relative 1RM, the result was similar. For GMed, the overall model was statistically significant (p < 0.001), explaining approximately 53.2% of the variance in EMG amplitude (R2 = 0.53). There also was a significant interaction between hip strength and sex (p = 0.011). Conditional analyses revealed a significant effect of hip strength on EMG amplitude for females (p < 0.001), but not for males (p = 0.40). For TFL, the overall model was not statistically significant (p = 0.99), explaining only 0.1% of the variance in EMG amplitude (R2 = 0.01). There was no significant interaction between hip strength and sex (p = 0.88), nor a significant main effect of absolute hip strength (p = 0.89) or sex (p = 0.88). Finally, after the Bonferroni correction, the interaction between hip strength and sex for GMed remained statistically significant.

Discussion

Our study aimed to investigate whether maximal hip abduction strength (absolute and relative) is associated with hip abductor EMG amplitude during single-leg stance, considering sex as a moderator. We observed that lower hip abduction strength was associated with greater activation of GMed only among females, without similar effect on TFL.

This study was motivated by the two reasonable explanations existing in the literature regarding the possibility of activating the muscles more or less during single-leg stance: more activation as a compensatory mechanism for reduced torque production capacity or less activation due to the inability of generating neural drive [20]. Applying similar concepts, hip abductor weakness has been frequently attributed as the reason for differences in EMG amplitude of hip abductors (mainly GMed) between groups in tasks involving single-leg stance [4,6,8].

We found that 51–53.2% of the variance in GMed amplitude during sustained single-leg stance was explained by hip abduction strength, sex, and their interaction. Specifically, the interaction between sex and strength indicated that lower levels of strength were associated with greater GMed amplitude only in females, which may support the hypothesis of a compensatory mechanism to maintain pelvic alignment [7,10]. Although we did not include kinematic measurements of the trunk or pelvis during our task, this mechanism is supported by a previous study showing that increased GMed activation was accompanying by reduced pelvic drop during walking while carrying a predetermined kettlebell weight in the contralateral hand [21]. Another possibility is that the lower tendon stiffness typically observed in females [22,23] may increase the demand for active muscle recruitment to stabilize the pelvis during single-leg stance. This hypothesis is explained by a compensated increase in muscle activation observed after a static-stretch intervention, causing a reduction in tendon stiffness [24], in order to improve the effectiveness of force generation and transmission [25]. However, in the absence of similar prior studies, this explanation remains speculative. Moreover, it’s possible that there is a limit to how much force levels can optimize neuromuscular economy, which might explain the absence of an association in males, given their greater strength compared to females. Finally, no comparable effect was observed for the TFL, likely due to its less prominent role in pelvic stability during single-leg tasks [26].

Our study found significant association during single-leg stance, which, although part of different single-leg tasks (e.g., walking, single-leg squat, single-leg landing, step-down) [1], is an isometric task. Therefore, to what extent our findings can be applied to more dynamic tasks remains unexplored. However, we hypothesize that the results may be similar for the following reasons. First, it is known that greater pelvic drop is associated with greater hip adduction during step-down tasks [27] and that lower GMed EMG activation was associated with higher hip adduction angle in single-leg tasks such as squatting, step-down, and landing [28]. Also, a meta-analysis found that lower dynamic hip abduction strength was moderately associated with greater hip adduction in single-leg tasks [29]. In all cited studies, the samples were predominantly female. Taken together, the established link between greater pelvic drop and increased hip adduction, along with the associations of reduced hip abductor strength and lower GMed activation with increased hip adduction across various dynamic single-leg tasks, supports the relevance of our isometric single-leg stance findings to more dynamic functional activities, particularly in female populations.

Although this compensatory increase in GMed activation may be effective in the short term, females with lower hip abduction strength may experience early fatigue, leading to altered lower limb movement patterns. This has important implications for sports that require single-leg control (e.g., running, soccer, basketball) and may help explain the higher incidence of certain injuries in females compared to males [3,4,14]. Therefore, strengthening the hip abductors may be particularly important in females to improve lower limb alignment during single-leg tasks.

Some important limitations need to be acknowledged: (i) we used the 1-RM test to assess the maximal force of hip abductors. Although this test is strongly associated with force measured by maximal isometric voluntary contractions [30], it is less commonly used than other types of strength assessments; (ii) the GMed is often functionally subdivided into three regions, which may limit the applicability of our results to tasks where the hip joint is in different positions (e.g., more flexed) or involves greater hip abductor moments (e.g., single-leg landing or cutting); (iii) our sample consisted of 36 participants for the moderation analysis. Therefore, we conducted a post hoc power analysis of the interaction effect using G*Power (f2 = 0.59, α = 0.05, n = 36), which indicated a statistical power greater than 0.95 to detect the interaction between hip strength and sex.

Conclusion

Females with lower hip abduction strength demonstrate greater GMed activation during single-leg stance, suggesting a sex-specific compensatory strategy. No similar effect was observed for TFL. These findings highlight the importance of considering sex in neuromuscular assessments of pelvic stability.

Supporting information

S1 Data. Database.

(PDF)

pone.0331553.s001.pdf (159.2KB, pdf)

Data Availability

All data are in the paper and/or supporting information files.

Funding Statement

The author(s) received no specific funding for this work.

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Decision Letter 0

Valentina Graci

14 Jul 2025

PONE-D-25-29454SEX AS A MODERATOR OF THE RELATIONSHIP BETWEEN HIP ABDUCTION STRENGTH AND MUSCLE ACTIVATION DURING SINGLE-LEG STANCEPLOS ONE

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5. If the reviewer comments include a recommendation to cite specific previously published works, please review and evaluate these publications to determine whether they are relevant and should be cited. There is no requirement to cite these works unless the editor has indicated otherwise. 

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Reviewers' comments:

Reviewer's Responses to Questions

Comments to the Author

1. Is the manuscript technically sound, and do the data support the conclusions?

The manuscript must describe a technically sound piece of scientific research with data that supports the conclusions. Experiments must have been conducted rigorously, with appropriate controls, replication, and sample sizes. The conclusions must be drawn appropriately based on the data presented.

Reviewer #1: No

Reviewer #2: Yes

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2. Has the statistical analysis been performed appropriately and rigorously?

Reviewer #1: No

Reviewer #2: Yes

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3. Have the authors made all data underlying the findings in their manuscript fully available?

The PLOS Data policy requires authors to make all data underlying the findings described in their manuscript fully available without restriction, with rare exception (please refer to the Data Availability Statement in the manuscript PDF file). The data should be provided as part of the manuscript or its supporting information, or deposited to a public repository. For example, in addition to summary statistics, the data points behind means, medians and variance measures should be available. If there are restrictions on publicly sharing data—e.g. participant privacy or use of data from a third party—those must be specified.

Reviewer #1: No

Reviewer #2: No

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4. Is the manuscript presented in an intelligible fashion and written in standard English?

PLOS ONE does not copyedit accepted manuscripts, so the language in submitted articles must be clear, correct, and unambiguous. Any typographical or grammatical errors should be corrected at revision, so please note any specific errors here.

Reviewer #1: Yes

Reviewer #2: Yes

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5. Review Comments to the Author

Please use the space provided to explain your answers to the questions above. You may also include additional comments for the author, including concerns about dual publication, research ethics, or publication ethics. (Please upload your review as an attachment if it exceeds 20,000 characters)

Reviewer #1: Dear Authors,

Thank you for the opportunity to review your manuscript. This study investigates an important and timely topic: whether sex moderates the relationship between hip abduction strength and muscle activation during a single-leg stance. The research question is well-motivated, and the finding of a sex-specific negative association in the gluteus medius is intriguing. The manuscript is generally well-written.

However, I have identified several major issues that need to be addressed before the manuscript can be considered for publication. My comments are detailed below.

Major Comments

1.The normalization of the TFL EMG data is a significant concern. The authors state that EMG amplitude was normalized to the MVIC of the GMed. As these are two different muscles with distinct functions and activation capacities, normalizing TFL activity to GMed's MVIC is methodologically inappropriate and likely invalidates all results reported for the TFL. The authors should either provide a strong justification for this unorthodox method or, ideally, re-normalize the TFL data using its own MVIC if that data is available. Otherwise, all analyses and conclusions regarding the TFL should be considered for removal from the manuscript.

2.The regression models do not appear to control for important potential confounders such as body mass and training history, which are critical confounders in strength analyses comparing males and females. I recommend including body size or composition covariates in the model or re-analyzing strength as a relative measure (e.g., normalized to body mass or lean mass) to ensure that the observed effects are not driven by body size alone.

3.The discussion repeatedly frames the increased GMed activation in weaker females as a compensatory strategy for pelvic stabilization. However, this interpretation assumes a functional outcome (i.e., improved pelvic control) that was not directly measured. Without kinematic data or stability-related performance outcomes, such as pelvic drop or trunk sway, this explanation remains speculative. Please consider revising the language to reflect that this is a hypothesis rather than a demonstrated mechanism, or alternatively, support the claim with additional evidence or references.

4.With only 36 participants and a sex-based interaction model, the power to detect interaction effects may be limited, especially given the potential data variance between groups. This raises concerns about Type II errors for nonsignificant findings (e.g., in males or for TFL) and potential overestimation of the observed effects in females. I suggest including a post-hoc power analysis for the interaction term, or at least discussing the limitations imposed by the sample size more explicitly in the Discussion section.

Minor Comments

1.For transparency and to assess estimate precision, I recommend reporting 95% confidence intervals (CIs) alongside β coefficients and p-values in all regression tables and/or main results text.

2.The manuscript does not report how failure to maintain single-leg stance was defined, or whether any trials were excluded due to poor task execution. This information is important for reproducibility. Please add a clear definition of task success/failure and any related exclusion criteria in the Methods section.

3.It is unclear whether participants performed the single-leg stance with eyes open or closed, which could affect balance strategy and neuromuscular activation. Please specify the visual condition used during testing and, if not standardized, discuss it as a limitation.

4.Although the interaction between sex and strength was not significant for TFL, it would be helpful to report or visualize sex-specific regression slopes, for comparison and transparency. If data permit, I suggest including a supplemental figure or text description.

5.The paper does not report whether regression assumptions were tested, such as residual normality, homoscedasticity, or multicollinearity. Please include a brief statement indicating that these assumptions were verified, or report diagnostics if available.

6.Since multiple regression models were used to test similar hypotheses for GMed and TFL, a correction for multiple testing (e.g., Bonferroni, Holm) may be warranted. If not applied, please justify this choice and address it as a potential limitation.

7.The 1RM estimation from submaximal trials is less common than MVIC in EMG studies and may introduce variability. While the authors cite evidence for its validity, a brief justification for selecting this method over MVIC would strengthen the Methods section.

8.The authors briefly mention lower tendon stiffness in females as a potential reason for increased GMed activation but do not provide enough detail. Expanding this part of the discussion would enhance the physiological plausibility of the interpretation.

9.Figure 1 provides a helpful visualization of the data. To further improve its clarity and impact, I suggest the authors add the regression lines for each group (males and females) to both plots. Including the 95% confidence bands for these lines would also be beneficial for interpreting the strength and precision of the observed associations.

10.In regression models with significant interaction terms, interpreting main effects independently can be misleading. Please consider rephrasing or de-emphasizing statements about the overall effect of strength across sexes, and focus interpretation within each subgroup.

11.The manuscript does not include a Data Availability Statement. The PLOS ONE policy requires such a statement to clarify for readers how the data can be accessed. Please add a formal statement detailing where the data is located or explaining any restrictions on its availability.

I look forward to seeing a revised version of this manuscript.

Reviewer #2: I appreciate the opportunity to review the manuscript entitled, “SEX AS A MODERATOR OF THE RELATIONSHIP BETWEEN HIP ABDUCTION STRENGTH

AND MUSCLE ACTIVATION DURING SINGLE-LEG STANCE” submitted to PLOS One. This study examined the impact of sex on hip abductor muscle function in the context of single leg stance as it relates to maximal muscle strength and muscle activation. The authors found that lower hip abduction strength was associated with greater activation of the glutes medius muscle in females but not males. The author argues this could represent a sex -specific compensatory strategy for this single leg stance control mechanism. Overall, this is a well written manuscript and in general the data supports the conclusion. I have a few questions and comments I would like the authors to address in terms of the methods and added discussion on the generalizability of the findings to clinical practice. I have provided section by section comments for the authors to consider and address.

Abstract: No edits

Introduction:

Overall, the introduction is well written and organized.

Methods:

Did the authors conduct an a priori power analysis to determine an adequate sample size for this study? If not, please justify the rationale for not doing one and add this to the manuscript.

Lines 108 -109 – Please mention this was a convenience sample.

Line 141 – Please provide the SENIAM guideline reference.

Lines 150-154 – Although the authors provide a reference with the detailed test description, I would add a short sentence or two that summarizes the methods of this estimated on rep max test. You must consider readers who are clinicians and do not have access to these important references for understanding the context of your study, especially since this method is a cornerstone of this investigation as it is how you measure muscle strength.

Lines 158 – I would briefly state that the PROCESS macro is an open-source package used for moderation analysis.

For example, I would just add: “…a moderation analysis was conduced using the PROCESS macro, model 1(version 4.0), which is an open-source package used for moderation analysis.”

Results:

Figure 1 – It would be helpful if the authors added trendlines indicating the relationship for each group, this would include showing the different slopes of the relationship.

Did the authors assess the data in figure 1 for outliers? This was not mentioned in the statistical analysis section. Linear models such as these are highly sensitive to outliers especially small samples.

Discussion:

The discussion does clearly report on the main findings and discusses them in the context of the other literature related to these findings. However, I would like to suggest that the authors consider their finding in the context of single limb control during a dynamic task like walking or single leg squat tasks. Do the authors think the relationship between would be sustained?

I think the authors need to discuss how generalizable these findings are to actual clinical practice. I would argue that in an athletic or highly active population that movement biomechanics of the participant play into this moderation based on dynamics of the system during the task. I would suggest adding a paragraph to discuss the generalizability of the findings to practice.

References: OK

Figure: See comment on adding linear regression lines to show different relationships among sex for each variable.

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Reviewer #1: No

Reviewer #2: No

**********

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Decision Letter 1

Valentina Graci

19 Aug 2025

SEX AS A MODERATOR OF THE RELATIONSHIP BETWEEN HIP ABDUCTION STRENGTH AND MUSCLE ACTIVATION DURING SINGLE-LEG STANCE

PONE-D-25-29454R1

Dear Dr. Rabello,

We’re pleased to inform you that your manuscript has been judged scientifically suitable for publication and will be formally accepted for publication once it meets all outstanding technical requirements.

Within one week, you’ll receive an e-mail detailing the required amendments. When these have been addressed, you’ll receive a formal acceptance letter and your manuscript will be scheduled for publication.

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If your institution or institutions have a press office, please notify them about your upcoming paper to help maximize its impact. If they’ll be preparing press materials, please inform our press team as soon as possible -- no later than 48 hours after receiving the formal acceptance. Your manuscript will remain under strict press embargo until 2 pm Eastern Time on the date of publication. For more information, please contact onepress@plos.org.

Kind regards,

Valentina Graci, PhD

Academic Editor

PLOS ONE

Additional Editor Comments (optional):

Reviewers' comments:

Reviewer's Responses to Questions

Comments to the Author

1. If the authors have adequately addressed your comments raised in a previous round of review and you feel that this manuscript is now acceptable for publication, you may indicate that here to bypass the “Comments to the Author” section, enter your conflict of interest statement in the “Confidential to Editor” section, and submit your "Accept" recommendation.

Reviewer #1: All comments have been addressed

Reviewer #2: All comments have been addressed

**********

2. Is the manuscript technically sound, and do the data support the conclusions?

The manuscript must describe a technically sound piece of scientific research with data that supports the conclusions. Experiments must have been conducted rigorously, with appropriate controls, replication, and sample sizes. The conclusions must be drawn appropriately based on the data presented.

Reviewer #1: Yes

Reviewer #2: Yes

**********

3. Has the statistical analysis been performed appropriately and rigorously?

Reviewer #1: Yes

Reviewer #2: Yes

**********

4. Have the authors made all data underlying the findings in their manuscript fully available?

The PLOS Data policy requires authors to make all data underlying the findings described in their manuscript fully available without restriction, with rare exception (please refer to the Data Availability Statement in the manuscript PDF file). The data should be provided as part of the manuscript or its supporting information, or deposited to a public repository. For example, in addition to summary statistics, the data points behind means, medians and variance measures should be available. If there are restrictions on publicly sharing data—e.g. participant privacy or use of data from a third party—those must be specified.

Reviewer #1: Yes

Reviewer #2: Yes

**********

5. Is the manuscript presented in an intelligible fashion and written in standard English?

PLOS ONE does not copyedit accepted manuscripts, so the language in submitted articles must be clear, correct, and unambiguous. Any typographical or grammatical errors should be corrected at revision, so please note any specific errors here.

Reviewer #1: Yes

Reviewer #2: Yes

**********

6. Review Comments to the Author

Please use the space provided to explain your answers to the questions above. You may also include additional comments for the author, including concerns about dual publication, research ethics, or publication ethics. (Please upload your review as an attachment if it exceeds 20,000 characters)

Reviewer #1: Dear Authors,

Thank you for your careful revisions and detailed responses to the comments from the previous round of review. I appreciate the effort you have put into improving the manuscript.

I have carefully reviewed the revised version and find that you have satisfactorily addressed all of my previous major and minor comments. In particular, I am pleased with the substantive changes you implemented, including correcting the TFL EMG normalization, re-analyzing for potential confounders, and adding a post-hoc power analysis. The expanded discussion, now supported by additional references, substantially enhances the physiological plausibility of your conclusions.

Overall, the manuscript is technically sound, the data support the conclusions, and it is clearly and coherently presented. I believe it is now ready for publication in *PLOS ONE*.

I commend the authors for their substantial efforts in strengthening the quality and clarity of the work.

Sincerely,

Reviewer #2: (No Response)

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7. PLOS authors have the option to publish the peer review history of their article (what does this mean? ). If published, this will include your full peer review and any attached files.

If you choose “no”, your identity will remain anonymous but your review may still be made public.

Do you want your identity to be public for this peer review? For information about this choice, including consent withdrawal, please see our Privacy Policy .

Reviewer #1: No

Reviewer #2: No

**********

Acceptance letter

Valentina Graci

PONE-D-25-29454R1

PLOS ONE

Dear Dr. Rabello,

I'm pleased to inform you that your manuscript has been deemed suitable for publication in PLOS ONE. Congratulations! Your manuscript is now being handed over to our production team.

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Kind regards,

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on behalf of

Dr. Valentina Graci

Academic Editor

PLOS ONE

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