Altered Co-contraction of Cervical Muscles in Young Adults with Chronic Neck Pain during Voluntary Neck Motions.
[Purpose] Muscle co-contraction is important in stabilizing the spine. The aim of this study was to compare cervical muscle co-contraction in adults with and without chronic neck pain during voluntary movements. [Subjects and Methods] Surface electromyography of three paired cervical muscles was measured in fifteen young healthy subjects and fifteen patients with chronic neck pain. The subjects performed voluntary neck movements in the sagittal and coronal plane at slow speed. The co-contraction ratio was defined as the normalized integration of the antagonistic electromyography activities divided by that of the total muscle activities. [Results] The results showed that the co-contraction ratio of patients was greater during flexion movement, lesser during extension movement, slightly greater during right lateral bending, and slightly lesser during left lateral bending compared with in the controls. [Conclusion] The results suggested that neck pain patients exhibit greater antagonistic muscle activity during flexion and dominate-side bending movements to augment spinal stability, while neuromuscular control provides relatively less protection in the opposite movements. This study helps to specify the changes of the stiffness of the cervical spine in neck pain patients and provides a useful tool and references for clinical assessment of neck disorders.
Department of Physical Therapy and Graduate Institute of Rehabilitation Science, College of Medicine, Chang Gung University, Taiwan ; Healthy Aging Research Center, Chang Gung University, Taiwan.
Chih-Hsiu
CH
Cheng
Graduate Institute of Early Intervention, College of Medicine, Chang Gung University, Taiwan.
Hsin-Yi Kathy
HY
Cheng
Department of Physical Medicine and Rehabilitation, Chang Gung Memorial Hospital at Linkou and College of Medicine, Chang Gung University, Taiwan.
Carl Pai-Chu
CP
Chen
Department of Physical Therapy, Tzu Chi University, Taiwan ; School and Graduate Institute of Physical Therapy, College of Medicine, National Taiwan University, Taipei City 100, Taiwan.
Kwan-Hwa
KH
Lin
Department of Physical Therapy and Graduate Institute of Rehabilitation Science, College of Medicine, Chang Gung University, Taiwan.
Wen-Yu
WY
Liu
School and Graduate Institute of Physical Therapy, College of Medicine, National Taiwan University, Taipei City 100, Taiwan ; Physical Therapy Center, National Taiwan University Hospital, Taiwan.
Shwu-Fen
SF
Wang
School and Graduate Institute of Physical Therapy, College of Medicine, National Taiwan University, Taipei City 100, Taiwan ; Physical Therapy Center, National Taiwan University Hospital, Taiwan.
Wei-Li
WL
Hsu
Department of Physical Therapy and Graduate Institute of Rehabilitation Science, College of Medicine, Chang Gung University, Taiwan ; Healthy Aging Research Center, Chang Gung University, Taiwan.
Yu-Fen
YF
Chuang
Chronic neck pain; Co-contraction; Electromyography