Firing rate trajectories of human motor units during activity-dependent muscle potentiation
Alexander M. Zero, Eric A. Kirk, Charles L. Rice
Abstract
During activity-dependent muscle potentiation (ADP), initial motor unit firing rate (MUFR) acceleration and the occurrence of MUFR trajectory saturation as a function of increasing contraction intensity were assessed. With no ADP (control), trajectories were more likely to accelerate and saturate (16/25 units) compared with voluntary- and stimulated-induced ADP conditions (4/25 and 8/25 units, respectively) that were fit better linearly. Therefore, during ADP, an attenuated intrinsic response to voluntary synaptic inputs occurs.
Topics & Concepts
Isometric exerciseLong-term potentiationMotor unitChemistryMuscle contractionContraction (grammar)ElectrophysiologyInternal medicineAnatomyEndocrinologyMedicineBiochemistryReceptorMuscle activation and electromyography studiesNeuroscience and Neural EngineeringMotor Control and Adaptation