Muscle prestimulation tunes velocity preflex in simulated perturbed hopping
Abstract Muscle fibres possess unique visco-elastic properties, which generate a stabilising zero-delay response to unexpected perturbations. This instantaneous response—termed “preflex”—mitigates neuro-transmission delays, which are hazardous during fast locomotion due to the short stance duration....
| Main Authors: | , , , , |
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| Format: | Article |
| Language: | English |
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Nature Portfolio
2023-03-01
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| Series: | Scientific Reports |
| Online Access: | https://doi.org/10.1038/s41598-023-31179-6 |
| _version_ | 1797864760146919424 |
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| author | Fabio Izzi An Mo Syn Schmitt Alexander Badri-Spröwitz Daniel F. B. Haeufle |
| author_facet | Fabio Izzi An Mo Syn Schmitt Alexander Badri-Spröwitz Daniel F. B. Haeufle |
| author_sort | Fabio Izzi |
| collection | DOAJ |
| description | Abstract Muscle fibres possess unique visco-elastic properties, which generate a stabilising zero-delay response to unexpected perturbations. This instantaneous response—termed “preflex”—mitigates neuro-transmission delays, which are hazardous during fast locomotion due to the short stance duration. While the elastic contribution to preflexes has been studied extensively, the function of fibre viscosity due to the force–velocity relation remains unknown. In this study, we present a novel approach to isolate and quantify the preflex force produced by the force–velocity relation in musculo-skeletal computer simulations. We used our approach to analyse the muscle response to ground-level perturbations in simulated vertical hopping. Our analysis focused on the preflex-phase—the first 30 ms after impact—where neuronal delays render a controlled response impossible. We found that muscle force at impact and dissipated energy increase with perturbation height, helping reject the perturbations. However, the muscle fibres reject only 15% of step-down perturbation energy with constant stimulation. An open-loop rising stimulation, observed in locomotion experiments, amplified the regulatory effects of the muscle fibre’s force–velocity relation, resulting in 68% perturbation energy rejection. We conclude that open-loop neuronal tuning of muscle activity around impact allows for adequate feed-forward tuning of muscle fibre viscous capacity, facilitating energy adjustment to unexpected ground-level perturbations. |
| first_indexed | 2024-04-09T22:58:29Z |
| format | Article |
| id | doaj.art-7deae4e756e940d3b52a77672e4b71b1 |
| institution | Directory Open Access Journal |
| issn | 2045-2322 |
| language | English |
| last_indexed | 2024-04-09T22:58:29Z |
| publishDate | 2023-03-01 |
| publisher | Nature Portfolio |
| record_format | Article |
| series | Scientific Reports |
| spelling | doaj.art-7deae4e756e940d3b52a77672e4b71b12023-03-22T11:09:26ZengNature PortfolioScientific Reports2045-23222023-03-0113111210.1038/s41598-023-31179-6Muscle prestimulation tunes velocity preflex in simulated perturbed hoppingFabio Izzi0An Mo1Syn Schmitt2Alexander Badri-Spröwitz3Daniel F. B. Haeufle4Hertie Institute for Clinical Brain Research and Center for Integrative Neuroscience, University of TübingenDynamic Locomotion Group, Max Planck Institute for Intelligent SystemsInstitute for Modelling and Simulation of Biomechanical Systems, University of StuttgartDynamic Locomotion Group, Max Planck Institute for Intelligent SystemsHertie Institute for Clinical Brain Research and Center for Integrative Neuroscience, University of TübingenAbstract Muscle fibres possess unique visco-elastic properties, which generate a stabilising zero-delay response to unexpected perturbations. This instantaneous response—termed “preflex”—mitigates neuro-transmission delays, which are hazardous during fast locomotion due to the short stance duration. While the elastic contribution to preflexes has been studied extensively, the function of fibre viscosity due to the force–velocity relation remains unknown. In this study, we present a novel approach to isolate and quantify the preflex force produced by the force–velocity relation in musculo-skeletal computer simulations. We used our approach to analyse the muscle response to ground-level perturbations in simulated vertical hopping. Our analysis focused on the preflex-phase—the first 30 ms after impact—where neuronal delays render a controlled response impossible. We found that muscle force at impact and dissipated energy increase with perturbation height, helping reject the perturbations. However, the muscle fibres reject only 15% of step-down perturbation energy with constant stimulation. An open-loop rising stimulation, observed in locomotion experiments, amplified the regulatory effects of the muscle fibre’s force–velocity relation, resulting in 68% perturbation energy rejection. We conclude that open-loop neuronal tuning of muscle activity around impact allows for adequate feed-forward tuning of muscle fibre viscous capacity, facilitating energy adjustment to unexpected ground-level perturbations.https://doi.org/10.1038/s41598-023-31179-6 |
| spellingShingle | Fabio Izzi An Mo Syn Schmitt Alexander Badri-Spröwitz Daniel F. B. Haeufle Muscle prestimulation tunes velocity preflex in simulated perturbed hopping Scientific Reports |
| title | Muscle prestimulation tunes velocity preflex in simulated perturbed hopping |
| title_full | Muscle prestimulation tunes velocity preflex in simulated perturbed hopping |
| title_fullStr | Muscle prestimulation tunes velocity preflex in simulated perturbed hopping |
| title_full_unstemmed | Muscle prestimulation tunes velocity preflex in simulated perturbed hopping |
| title_short | Muscle prestimulation tunes velocity preflex in simulated perturbed hopping |
| title_sort | muscle prestimulation tunes velocity preflex in simulated perturbed hopping |
| url | https://doi.org/10.1038/s41598-023-31179-6 |
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