Kumar Shrawan, Narayan Yogesh, Amell Tyler
Department of Physical Therapy, 3-75 Corbett Hall, University of Alberta, Edmonton, Alberta T6G 2G4, Canada.
Spine J. 2003 Sep-Oct;3(5):339-50. doi: 10.1016/s1529-9430(03)00077-9.
There is relatively little known concerning the spectral profile of the cervical muscles, despite the fact that neck injury and pain are quite prevalent.
The objective of the study was to calculate and study the power spectral characteristics of the sternocleidomastoids, splenii capitis and upper trapezii in anterolateral flexion and posterolateral extension in a ramp contraction.
STUDY DESIGN/SETTING: In a laboratory setting experiments were conducted to record surface electromyographic (EMG) data from six cervical muscles and power spectral variables obtained.
Forty normal and healthy young adults (21 men, 19 women).
Power spectral of EMG signals.
EMG data for the left and right isometric anterolateral flexion and posterolateral extension were acquired from the sternocleidomastoids, splenii capitis and upper trapezius bilaterally. The subjects were seated in an upright posture and exerted left and right anterolateral flexor and posterolateral extensor efforts from rest to their maximal voluntary contraction in a gradual linear ramp fashion using visual feedback as a guide. The force exerted and the surface EMG data were sampled at 1 kHz at every 10th percentile grade of contraction and the EMG data were subjected to the Fast-Fourier transform analysis. The median frequency (MF), mean power frequency (MPF), peak power and total power of all six cervical muscles were analyzed.
In the anterolateral flexion the ipsilateral sternocleidomastoid and splenius capitis had a wider band of frequency, which further widened with increasing grade of contraction. The trapezius did not engage in the same manner or to the same magnitude. The MF of the sternocleidomastoid in the anterolateral flexion in both genders progressively increased, the splenius capitis remained relatively unchanged, and the upper trapezius declined with the increasing grades of contraction.
There is no significant difference between the genders in spectral profile. There is a bilateral symmetry in spectral profile with reference to activity; however, they are significantly different in different activities for the same muscles. With increasing magnitude of contraction power, spectral density distribution increases and the median frequency decreases. These results can serve as a useful reference for painful necks. Restoration of power spectral characteristics may indicate normalcy, which cannot be gleaned by other EMG or force variables.
尽管颈部损伤和疼痛相当普遍，但关于颈部肌肉的频谱特征却知之甚少。
本研究的目的是计算并研究胸锁乳突肌、头夹肌和上斜方肌在斜坡收缩时前外侧屈曲和后外侧伸展的功率谱特征。
研究设计/场所：在实验室环境中进行实验，记录来自六块颈部肌肉的表面肌电图（EMG）数据并获得功率谱变量。
40名正常健康的年轻人（21名男性，19名女性）。
EMG信号的功率谱。
双侧从胸锁乳突肌、头夹肌和上斜方肌获取左右等长前外侧屈曲和后外侧伸展的EMG数据。受试者坐姿端正，在视觉反馈的引导下，以逐渐线性斜坡的方式从休息状态开始，将左右前外侧屈肌和后外侧伸肌的力量从休息状态逐渐增加到最大自主收缩。在收缩的每10%等级时，以1kHz的频率对施加的力和表面EMG数据进行采样，并对EMG数据进行快速傅里叶变换分析。分析了所有六块颈部肌肉的中位频率（MF）、平均功率频率（MPF）、峰值功率和总功率。
在前外侧屈曲时，同侧胸锁乳突肌和头夹肌的频率带较宽，且随着收缩等级的增加进一步变宽。斜方肌的参与方式和程度不同。两性胸锁乳突肌在前外侧屈曲时的MF逐渐增加，头夹肌相对保持不变，而上斜方肌随着收缩等级的增加而下降。
频谱特征在性别之间无显著差异。频谱特征在活动方面存在双侧对称性；然而，同一肌肉在不同活动中存在显著差异。随着收缩力量的增加，频谱密度分布增加，中位频率降低。这些结果可为颈部疼痛提供有用的参考。功率谱特征的恢复可能表明正常状态，这是其他EMG或力量变量无法获取的。
