Spinal and supraspinal mechanisms affecting torque development at different joint angles |
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| Authors: | Maria Papaiordanidou PHD Valérie Mustacchi MSC Jean‐Damien Stevenot MSC Michele Vanoncini PHD Alain Martin PR |
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| Affiliation: | 1. UMR7287, CNRS, Aix‐Marseille University, Marseille, France;2. INSERM U1093 Cognition, Action et Plasticité Sensorimotrice, Université de Bourgogne, UFR STAPS, Dijon, France |
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| Abstract: | Introduction: We examined the neural mechanisms responsible for plantar flexion torque changes at different joint positions. Methods: Nine subjects performed maximal voluntary contractions (MVC) at 6 ankle–knee angle combinations [3 ankle angles (dorsiflexion, anatomic position, plantar flexion) and 2 knee angles (flexion, full extension)]. Neural mechanisms were determined by V‐wave, H‐reflex (at rest and during MVC), and electromyography during MVC (RMS), normalized to the muscle compound action potential (V/Msup, Hmax/Mmax, Hsup/Msup and RMS/Msup) and voluntary activation (VA), while muscle function was assessed by doublet amplitude. Results: MVC and doublet amplitude were significantly lower at plantar flexion (P < 0.01), while VA was significantly lower at dorsiflexion and full knee extension (P < 0.05). V/Msup and RMS/Msup were significantly lower at knee extension (P < 0.01), while Hsup/Msup was not affected by joint angle. Conclusions: These results indicate that joint positions leading to muscle lengthening produce reduced neural drive, due mainly to supraspinal mechanisms. Muscle Nerve 53 : 626–632, 2016 |
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| Keywords: | electromyography muscle mechanical properties neural activation spinal excitability twitch interpolation |
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