The Effects of Varying Intensities of Unilateral Handgrip Fatigue on Bilateral Movement

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

Congratulations. You have done a good work. 

hera are some comments:

Review

 

Please put the references this way:

e.g., line 53

force’ [2].

 

Separate the reference from the previous word, e.g., line 101, muscle [5] or page 107 M1, [8]

 

Upon the first appearance of the term GABA, it would be helpful to clarify its function as an inhibitory neurotransmitter in the brain. This would allow non-specialists to better understand the rationale behind the study.

 

Line 104

TMS – explain this acronym

 

Line 125

GABA-ergic signalling? GABA is inhibitory not ergic. Decrease of GABA yes, is ergic.

 

Line 130

You opened the sentence from Swinnen but it is not closed afterwards

 

Question: Given such distinct levels of muscle tension among trials, the authors thought that the Borg scale would contradict the results regarding fatigue?

 

Line 446

to probe: 1)

Line 448

hypotheses, and 2)

Line 493

that:

Line 496

compare,

I think some abbreviations are redundant. They are clearly expressed within the text.

Most journals are written in abbreviated form, while some are written in full. E.g., reference 11

Author Response

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Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and Suggestions for Authors

Major Revision

Comments for author File: Comments.pdf

Author Response

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Author Response File: Author Response.pdf

Reviewer 3 Report

Comments and Suggestions for Authors

This study explored whether tiring one hand through repeated grip contractions at different intensities (5%, 50%, and 75% of maximum voluntary contraction) would influence how both arms perform during a more complex, bilateral movement task. Thirty healthy participants first completed the fatigue protocols and then carried out an object-hit task using a Kinarm robotic system. As expected, the moderate and high-intensity conditions produced clear signs of fatigue, including reduced force output, altered EMG activity, lower post-exercise MVC, and higher perceived exertion. Despite these physiological changes, participants showed no meaningful differences in either arm’s movement quality—such as the number of hits, velocity, acceleration, or workspace coverage. Overall, the findings suggest that unilateral handgrip fatigue, even when substantial, does not lead to measurable changes in higher-level bilateral arm performance.

Here are my suggestions: 

1. Clarify the mechanistic rationale earlier by explaining how GABA-related disinhibition might influence bilateral motor behavior.
2. Enhance ecological relevance by adding real-world or clinical examples that show why unilateral fatigue effects matter.
3. Discuss task-specificity in greater depth and address why the object-hit task may not capture neural effects observed in simpler button-press paradigms.
4. Improve data presentation by integrating key fatigue markers—force, EMG, MVC, and perceived exertion—into a single, easy-to-compare figure.
5. Strengthen the limitations section by addressing sample size, single-session design, and the mismatch between the fatiguing and assessment tasks, and suggest task-matched approaches for future studies.

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Round 2

Reviewer 2 Report

Comments and Suggestions for Authors

The authors addressed all my comments, and the revised manuscript is acceptable.