Motor modules are largely unaffected by pathological walking biomechanics: a simulation study
Abstract Background Motor module (a.k.a. muscle synergy) analysis has frequently been used to provide insight into changes in muscle coordination associated with declines in walking performance, to evaluate the effect of different rehabilitation interventions, and more recently, to control exoskelet...
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BMC
2025-01-01
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| Series: | Journal of NeuroEngineering and Rehabilitation |
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| Online Access: | https://doi.org/10.1186/s12984-025-01561-8 |
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| author | Mohammad Rahimi Goloujeh Jessica L. Allen |
| author_facet | Mohammad Rahimi Goloujeh Jessica L. Allen |
| author_sort | Mohammad Rahimi Goloujeh |
| collection | DOAJ |
| description | Abstract Background Motor module (a.k.a. muscle synergy) analysis has frequently been used to provide insight into changes in muscle coordination associated with declines in walking performance, to evaluate the effect of different rehabilitation interventions, and more recently, to control exoskeletons and prosthetic devices. However, it remains unclear whether changes in muscle coordination revealed via motor module analysis stem from abnormal walking biomechanics or neural control. This distinction has important implications for the use of motor module analysis for rehabilitation interventions and device design. Thus, this study aims to elucidate the extent to which motor modules emerge from pathological walking biomechanics, i.e. abnormal walking biomechanics commonly observed in individuals with neurological disease and/or injury. Methods We conducted a series of computer simulations using OpenSim Moco to simulate pathological walking biomechanics by manipulating speed, asymmetry, and step width in a three-dimensional musculoskeletal model. We focused on these spatiotemporal metrics because they are commonly altered in individuals with Parkinson’s disease, stroke survivors, etc. and have been associated with changes in motor module number and structure. We extracted motor modules using nonnegative matrix factorization from the muscle activations from each simulation. We then examined how alterations in walking biomechanics influenced the number and structure of extracted motor modules and compared the findings to previous experimental studies. Results The motor modules identified from our simulations were similar to those identified from previously published experiments of non-pathological walking. Moreover, our findings indicate that the same motor modules can be used to generate a range of pathological-like waking biomechanics by modulating their recruitment over the gait cycle. These results contrast with experimental studies in which pathological-like walking biomechanics are accompanied by a reduction in motor module number and alterations in their structure. Conclusions This study highlights that pathological walking biomechanics do not necessarily require abnormal motor modules. In other words, changes in number and structure of motor modules can be a valuable indicator of alterations in neuromuscular control and may therefore be useful for guiding rehabilitation interventions and controlling exoskeletons and prosthetic devices in individuals with impaired walking function due to neurological disease or injury. |
| format | Article |
| id | doaj-art-c54ed78df3c44e859093652dbc86b7c4 |
| institution | Kabale University |
| issn | 1743-0003 |
| language | English |
| publishDate | 2025-01-01 |
| publisher | BMC |
| record_format | Article |
| series | Journal of NeuroEngineering and Rehabilitation |
| spelling | doaj-art-c54ed78df3c44e859093652dbc86b7c42025-02-02T12:11:47ZengBMCJournal of NeuroEngineering and Rehabilitation1743-00032025-01-0122111810.1186/s12984-025-01561-8Motor modules are largely unaffected by pathological walking biomechanics: a simulation studyMohammad Rahimi Goloujeh0Jessica L. Allen1Department of Mechanical and Aerospace Engineering, University of FloridaDepartment of Mechanical and Aerospace Engineering, University of FloridaAbstract Background Motor module (a.k.a. muscle synergy) analysis has frequently been used to provide insight into changes in muscle coordination associated with declines in walking performance, to evaluate the effect of different rehabilitation interventions, and more recently, to control exoskeletons and prosthetic devices. However, it remains unclear whether changes in muscle coordination revealed via motor module analysis stem from abnormal walking biomechanics or neural control. This distinction has important implications for the use of motor module analysis for rehabilitation interventions and device design. Thus, this study aims to elucidate the extent to which motor modules emerge from pathological walking biomechanics, i.e. abnormal walking biomechanics commonly observed in individuals with neurological disease and/or injury. Methods We conducted a series of computer simulations using OpenSim Moco to simulate pathological walking biomechanics by manipulating speed, asymmetry, and step width in a three-dimensional musculoskeletal model. We focused on these spatiotemporal metrics because they are commonly altered in individuals with Parkinson’s disease, stroke survivors, etc. and have been associated with changes in motor module number and structure. We extracted motor modules using nonnegative matrix factorization from the muscle activations from each simulation. We then examined how alterations in walking biomechanics influenced the number and structure of extracted motor modules and compared the findings to previous experimental studies. Results The motor modules identified from our simulations were similar to those identified from previously published experiments of non-pathological walking. Moreover, our findings indicate that the same motor modules can be used to generate a range of pathological-like waking biomechanics by modulating their recruitment over the gait cycle. These results contrast with experimental studies in which pathological-like walking biomechanics are accompanied by a reduction in motor module number and alterations in their structure. Conclusions This study highlights that pathological walking biomechanics do not necessarily require abnormal motor modules. In other words, changes in number and structure of motor modules can be a valuable indicator of alterations in neuromuscular control and may therefore be useful for guiding rehabilitation interventions and controlling exoskeletons and prosthetic devices in individuals with impaired walking function due to neurological disease or injury.https://doi.org/10.1186/s12984-025-01561-8Muscle coordination complexityGait analysisComputer modelingOptimal controlTrajectory optimizationDirect collocation |
| spellingShingle | Mohammad Rahimi Goloujeh Jessica L. Allen Motor modules are largely unaffected by pathological walking biomechanics: a simulation study Journal of NeuroEngineering and Rehabilitation Muscle coordination complexity Gait analysis Computer modeling Optimal control Trajectory optimization Direct collocation |
| title | Motor modules are largely unaffected by pathological walking biomechanics: a simulation study |
| title_full | Motor modules are largely unaffected by pathological walking biomechanics: a simulation study |
| title_fullStr | Motor modules are largely unaffected by pathological walking biomechanics: a simulation study |
| title_full_unstemmed | Motor modules are largely unaffected by pathological walking biomechanics: a simulation study |
| title_short | Motor modules are largely unaffected by pathological walking biomechanics: a simulation study |
| title_sort | motor modules are largely unaffected by pathological walking biomechanics a simulation study |
| topic | Muscle coordination complexity Gait analysis Computer modeling Optimal control Trajectory optimization Direct collocation |
| url | https://doi.org/10.1186/s12984-025-01561-8 |
| work_keys_str_mv | AT mohammadrahimigoloujeh motormodulesarelargelyunaffectedbypathologicalwalkingbiomechanicsasimulationstudy AT jessicalallen motormodulesarelargelyunaffectedbypathologicalwalkingbiomechanicsasimulationstudy |