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Spinal and supraspinal mechanisms affecting torque development at different joint angles
Author(s) -
Papaiordanidou Maria,
Mustacchi Valérie,
Stevenot JeanDamien,
Vacini Michele,
Martin Alain
Publication year - 2016
Publication title -
muscle and nerve
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.025
H-Index - 145
eISSN - 1097-4598
pISSN - 0148-639X
DOI - 10.1002/mus.24895
Subject(s) - physical medicine and rehabilitation , joint (building) , torque , medicine , neuroscience , anatomy , psychology , physics , structural engineering , engineering , thermodynamics
: 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/M sup , H max /M max , H sup /M sup and RMS/M sup ) 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/M sup and RMS/M sup were significantly lower at knee extension ( P < 0.01), while H sup /M sup 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