Comparing arm to whole-body motor control disambiguates age-related deterioration from compensationuse asterix (*) to get italics

Robin Mathieu, Florian Chambellant, Elizabeth Thomas, Charalambos Papaxanthis, Pauline Hilt, Patrick Manckoundia, France Mourey, Jeremie GaveauPlease use the format "First name initials family name" as in "Marie S. Curie, Niels H. D. Bohr, Albert Einstein, John R. R. Tolkien, Donna T. Strickland"

2024

<p>As the global population ages, it is crucial to understand sensorimotor compensation mechanisms. These mechanisms are thought to enable older adults to remain in good physical health, but despite important research efforts, they remain essentially chimeras. A major problem with their identification is the ambiguous interpretation of age-related alterations. Whether a change reflects deterioration or compensation is difficult to determine. Here we compared the electromyographic and kinematic patterns of different motor tasks in younger (n = 20; mean age = 23.6 years) and older adults (n = 24; mean age = 72 years). Building on the knowledge that humans take advantage of gravity effects to minimize their muscle effort, we probed the ability of younger and older adults to plan energetically efficient movement during arm-only and whole-body movements. In line with previous studies and compared to younger adults, muscle activation patterns revealed that older adults used a less efficient movement strategy during whole-body movement tasks. We found that this age-related alteration was task-specific. It did not affect arm movements, thereby supporting the hypothesis that healthy older adults maintain the ability to plan energetically efficient movements. More importantly, we found that the reduced whole-body movement efficiency was correlated with kinematic measures of balance control (i.e., the center-of-mass movement amplitude and speed). The more efficient the movement strategy, the more challenging the balance. Overall, these results suggest that reduced movement efficiency in healthy older adults does not reflect a deterioration but rather a compensation process that adapts movement strategy to the task specificities. When balance is at stake, healthy older adults prefer stability to energy efficiency.</p>

https://doi.org/10.5281/zenodo.10619701You should fill this box only if you chose 'All or part of the results presented in this preprint are based on data'. URL must start with http:// or https://

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https://doi.org/10.5281/zenodo.10634004You should fill this box only if you chose 'Codes have been used in this study'. URL must start with http:// or https://

Aging, motor control, electromyography, gravity, sensorimotor compensation, equilibrium, posture

NonePlease indicate the methods that may require specialised expertise during the peer review process (use a comma to separate various required expertises).

Biomechanics, Sensorimotor Control

Matthieu Casteran, matthieu.casteran@univ-lorraine.fr, Kaitlin Cassady, kcass@umich.edu, Andrea d'Avella, a.davella@hsantalucia.it, Tibor Hortobágyi, hortobagyit@ecu.edu, Tyler Fettrow, tfettrow@gmail.com, Boris Cheval, boris.cheval@unige.ch, Pierre Morel, pier.morel@gmail.com, Jessica C. Selinger, j.selinger@queensu.ca, Sylvie Vernazza-Martin, Sylvie.martin@u-paris10.fr, Rachael D. Seidler, rseidler@umich.edu, Matthieu Casteran [matthieu.casteran@univ-lorraine.fr] suggested: lionel bringoux : lionel.bringoux@univ-amu.fr, Andrea d'Avella [a.davella@hsantalucia.it] suggested: Marta Russo (m.russo@hsantalucia.it), Florian Monjo suggested: Nicolas Forestier, Sina Mehdizadeh suggested: major comments:, Sina Mehdizadeh suggested: - The abstract needs a complete re-organization and also needs to include more info about the methods, results, and conclusions. , Sina Mehdizadeh suggested: - I think the Introduction can be shortened and focused more on the specific gap the study is investigating, compensatory mechanisms in fine movements in older adults. , Sina Mehdizadeh suggested: - It is not clear what type of adaptations are required in these simple tasks. In other words, why these tasks were chosen is not clear. This needs to be justified in the Intro or briefly in the Methods., Sina Mehdizadeh suggested: - the authors mentioned in the Intro that they are investigating compensatory mechanisms at the behavioural level but they are doing the analysis based on EMG signals. The EMG signals are at the cellular level (motor units). I am not sure this is considered behaviour., Sina Mehdizadeh suggested: - it is not clear why an ML analysis was needed when they could statistically compare the EMG metrics between the groups., Sina Mehdizadeh suggested: - if the simple arm movement tasks did not show compensatory mechanism differences, then the authors' claim in the Intro that simple tasks are needed to study this mechanism is not valid., Sina Mehdizadeh suggested: - Overall, I am not convinced about this conclusion: "Overall, the present results suggest a compensation process, Sina Mehdizadeh suggested: that modulates planning strategies to maximize equilibrium in older adults. ", Sina Mehdizadeh suggested: minor comments:, Sina Mehdizadeh suggested: - the first four lines of the abstract can be shortened to focus more on the specific problem the study is targeting. , Sina Mehdizadeh suggested: - lines 28-31 belong to the intro of the abstract , Sina Mehdizadeh suggested: - only oral consent? no written?, Florian Monjo suggested: I appreciate the authors' significant efforts in revising the manuscript. Overall, they have satisfactorily addressed my comments. However, a few minor issues remain, particularly some errors in the text., Florian Monjo suggested: Line 216: Please replace “analyse” with “analysis.”, Florian Monjo suggested: Line 219: Remove the parenthesis before "Winter" and place it before the year., Florian Monjo suggested: Line 222: Replace “ofsset” with “offset.”, Florian Monjo suggested: Line 230: Replace “rational” with “rationale.”, Florian Monjo suggested: Line 234: Enclose the year in parentheses., Florian Monjo suggested: Line 301: Consider revising the sentence to: "Scientific literature has reported that the control of whole-body movements changes with age, while the control of arm movements does not.", Florian Monjo suggested: Line 483: Remove the "s" from "harvests.", Florian Monjo suggested: Regarding your response to the comment on oral consent ("The French National Ethics Committee (2019-A01558-49) approved the experiment to be conducted with oral informed consent only. Nonetheless, each participant was included in the study by a medical doctor."), it might be worth incorporating this information into the text.

e.g. John Doe john@doe.com

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2024-02-19 10:41:33

Matthieu Boisgontier