Spinal and supraspinal mechanisms affecting torque development at different joint angles
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Updated: Apr 4, 2026

Quantifying Learning in Young Infants: Tracking Leg Actions During a Discovery-learning Task
Published on: June 1, 2015
Maria Papaiordanidou1, Valérie Mustacchi1, Jean-Damien Stevenot1
1UMR7287, CNRS, Aix-Marseille University, 163 avenue de Luminy, 13288, Marseille, France.
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.
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