PNF and Movement 2021; 19(2): 194-203
Changes in Nerve Excitability Depending on Intensity of Neural Stretching
Jong-Soon Kim, P.T., Ph.D.
Department of Physical Therapy, College of Health Sciences, Catholic University of Pusan
Correspondence to: Jong-Soon Kim (
Received: June 15, 2021; Revised: July 14, 2021; Accepted: July 21, 2021; Published online: August 31, 2021.
© Korea Proprioceptive Neuromuscular Facilitation Association. All rights reserved.

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Purpose: Neurodynamic tests are used to examine neural tissue in patients with neuro-musculoskeletal disorders, although this has not yet been established in the intensity of nerve tension application. This study aimed to investigate the acute effects of neural stretching intensity on nerve excitability using the latency and amplitude of nerve conduction velocity test (NCV) analysis.
Methods: Thirty young, healthy male and female subjects (mean age = 21.30 years) voluntarily participated in this study. Nerve excitability was assessed using the median sensory NCV test. The latency and amplitude of the NCV test were measured under four different conditions: reference phase (supra-maximal stimulus, without neural stretching), baseline phase (2/3 of the supra-maximal stimulus, without neural stretching), weak stretch phase (2/3 of the supra-maximal stimulus, with weak neural stretching), and strong stretch phase (2/3 of the supra-maximal stimulus, with strong neural stretching).
Results: The NCV latency was significantly delayed after one minute of neural stretching at the baseline, weak phase, and strong phase in comparison with the reference phase. The NCV latency was significantly delayed by increasing the strength of neural stretching. Furthermore, the NCV amplitude was significantly increased at the weak and strong phases, which were under neural stretching, in comparison with the baseline phase. The NCV amplitude was significantly increased by increasing the strength of the neural stretching.
Conclusion: Transient neural stretching as a neurodynamic test can increase the sensitivity of the nerve without negatively affecting the nervous system. However, based on the results of this study, strong neural stretching in the neurodynamic test may delay the transmission of nerve impulses and hypersensitivity.
Keywords: Neurodynamic test, Neural stretching, Nerve conduction velocity test, Nerve excitability

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