Study on Electromyographic Characteristics of Neck Muscles in College Students with Chronic Neck Pain
Authors: Yan Yanqing , Li Guan , Cai Feng , Liu Xiaoguang , Zhao Ge , Li Chunlan , Yuan Yafei , Du Ziwei 
Published: May 2023

Abstract
Objectives To provide reference for the evaluation and diagnosis of chronic neck pain (CNP) syndrome.
Methods 22 patients with CNP and 22 healthy people were recruited from South China Normal University, who were all college students. The subjects’ neck extensor muscle strength in head neutral position, natural anteversion position and maximum forward flexion position was measured by a tester for isometric muscle strength respectively. The static electromyography (EMG) of the subjects’ splenius capitis muscles and upper trapezius muscles was detected by a surface EMG device during isometric contractions of muscles, and the dynamic EMG of the subjects’ splenius capitis muscles and upper trapezius muscles was detected during head and neck flexion and extension. Neck extensor muscle strength, average electromyography (AEMG), integral electromyography (iEMG), rate of EMG contribution and flexion extension ratio (FER) in patients and healthy subjects were compared to find out electromyographic characteristics of neck muscles in college students with CNP.
Results (1) There were very significant differences in the maximum isometric muscle strength of neck extensor muscles between patients with CNP and healthy subjects in head neutral position, head natural forward position and head maximum flexion position (P < 0.001). (2) There were very significant differences in the average EMG of the neck muscle, which was isometrically contracted, between patients with CNP and healthy subjects in the head neutral position, head natural forward position, and head maximum flexion position (P < 0.001). (3) There were significant differences in the integral electromyography of the neck muscle, which was isometrically contracted, between patients with CNP and healthy subjects in the head neutral position, head natural forward position, and head maximum flexion position (P < 0.005). (4) In the head neutral position of patients with CNP and healthy people, the rates of integral electromyography contribution were respectively 51.5% and 53.9% (splenius capitis muscle)，and were respectively 48.4% and 45.3% (trapezius muscle) during an isometric contraction of neck muscles. In the natural anteversion position of the head，the values were respectively 49.1% and 54.0% (splenius capitis muscle)，and were respectively 50.8% and 45.9% (trapezius muscle). In the maximum anteflexion position of the head，the values were respectively 47.7% and 52.6% (splenius capitis muscle)，and were respectively 52.1% and 47.3% (trapezius muscle). (5) During neck muscles anteflexion of patients with CNP and healthy people，the averaged electromyography of splenius capitis muscles and trapezius muscles adds respectively up to 62.99 μv and 55.79 μv. There was a significant difference（P＜0.007）. During backward extension, the averaged electromyography adds respectively up to 64.75 μv and 79.22 μv. There was a significant difference ( P < 0.001 ). The flexion extension ratios of neck muscles in the two groups were respectively 0.95 and 0.62 on average. There was a significant difference（P＜0.001）.
Conclusions (1) Both neck extensor muscle strength and EMG level of college students with CNP were significantly lower than those of healthy college students. (2) Both splenius capitis muscles and trapezius muscles of college students with CNP had functional damage, and the functional damage of the former was severer. (3) During head and neck flexion and extension, FER of neck extensor muscle EMG in college students with CNP significantly increased, indicating that the active activity functions of neck extensor muscles of college students with CNP were insufficient and the flexion-relaxation responses were weakened.