New insights into the potentiation of the first and second phases of the M-wave after voluntary contractions in the quadriceps muscle
Introduction: We investigated the mechanisms underlying the potentiation of the first and second phases of the compound action potential (M-wave) after conditioning contractions. Methods: M-waves were evoked in the knee extensors before and after isometric maximal voluntary contractions (MVCs) of 1...
| Autores: | , |
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| Tipo de recurso: | artículo |
| Estado: | Versión aceptada para publicación |
| Fecha de publicación: | 2016 |
| 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:2454/55611 |
| Acceso en línea: | https://hdl.handle.net/2454/55611 |
| Access Level: | acceso abierto |
| Palabra clave: | Electromyography M-wave potentiation Femoral nerve stimulation Muscle excitability Muscle architecture Conduction velocity |
| Sumario: | Introduction: We investigated the mechanisms underlying the potentiation of the first and second phases of the compound action potential (M-wave) after conditioning contractions. Methods: M-waves were evoked in the knee extensors before and after isometric maximal voluntary contractions (MVCs) of 1 s, 3 s, 6 s, 10 s, 30 s, and 60 s. The amplitude, duration, and area of the M-wave first and second phases were measured during the 10-min period after each contraction. Results: The magnitude of the M-wave first phase was enlarged only after MVCs of 30 s and 60 s, whereas the second phase increased after all MVCs, regardless of their duration. The enlargement of the first phase remained for longer than 2 min, whereas the potentiation of the second phase lasted only 20 s. Conclusions: Potentiation of the first phase is the result of fatigue-induced membrane changes, whereas enlargement of the second phase is probably related to shortening of muscle fascicles. |
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