Spinal and supraspinal mechanisms affecting torque development at different joint angles

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 fle...

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Bibliographic Details
Published in:Muscle & nerve 2016-04, Vol.53 (4), p.626-632
Main Authors: Papaiordanidou, Maria, Mustacchi, Valérie, Stevenot, Jean-Damien, Vanoncini, Michele, Martin, Alain
Format: Article
Language:English
Subjects:
Adult
Ankle
Ankle Joint - physiology
electromyography
Electromyography - methods
Female
H-Reflex - physiology
Humans
Knee
Knee Joint - physiology
Male
Muscle Contraction - physiology
muscle mechanical properties
Muscle, Skeletal - physiology
neural activation
spinal excitability
Torque
twitch interpolation
Young Adult
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Summary: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
ISSN:0148-639X
1097-4598
DOI:10.1002/mus.24895