Power spectral changes of the superimposed M wave during isometric voluntary contractions of increasing strength
Introduction: We examined the power spectralchanges of the compound muscle action potential (M wave)evoked during isometric contractions of increasing strength.Methods: Surface electromyography (sEMG) of the vastus later-alis and medialis was recorded from 20 volunteers who per-formed 4-s step-wise...
| Autores: | , |
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| Tipo de recurso: | artículo |
| Estado: | Versión aceptada para publicación |
| Fecha de publicación: | 2015 |
| País: | España |
| Institución: | Universidad Pública de Navarra |
| Repositorio: | Academica-e. Repositorio Institucional de la Universidad Pública de Navarra |
| OAI Identifier: | oai:academica-e.unavarra.es:2454/55582 |
| Acceso en línea: | https://hdl.handle.net/2454/55582 |
| Access Level: | acceso abierto |
| Palabra clave: | Superimposed M-wave Surface EMG spectral analysis Median frequency Step-wise contractions Femoral nerve stimulation |
| Sumario: | Introduction: We examined the power spectralchanges of the compound muscle action potential (M wave)evoked during isometric contractions of increasing strength.Methods: Surface electromyography (sEMG) of the vastus later-alis and medialis was recorded from 20 volunteers who per-formed 4-s step-wise isometric contractions of differentintensities. A maximal M wave was elicited by a single stimulusto the femoral nerve and superimposed on the voluntary con-tractions. The spectral characteristics (Fmean and Fmedian) ofsEMG and M-wave signals were calculated. Results: M-wavespectral indicators increased systematically with contractionintensity up to 60% MVC and then leveled off at higher forces.Over the 10–60% MVC range, the increase in spectral indica-tors was 3 times higher for M waves (36%) than for sEMG(12%). Conclusions: The consistent increase in M-wave spectralcharacteristics with force is due to the fact that the number ofmotor units recruited by the superimposed supramaximal stimu-lus is approximately stable. |
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