Falla D, Rainoldi A, Jull G, Stavrou G, Tsao H
Division of Physiotherapy, The University of Queensland, Brisbane, Qld 4072, Australia.
Neurophysiol Clin. 2004 Oct;34(3-4):159-65. doi: 10.1016/j.neucli.2004.04.004.
Despite the evidence of greater fatigability of the superficial cervical flexor muscles in neck pain patients, the relationship between duration of neck pain and muscle fatigue has not been investigated. This study examined the relationship between myoelectric manifestations of sternocleidomastoid (SCM) and anterior scalene (AS) muscle fatigue and duration of neck pain in a group of patients with chronic neck pain.
Twenty chronic neck pain patients with a history of pain ranging between 1 and 25 years (mean 6.15, S.D. 5.48 years) participated in this study. Myoelectric signals were recorded from the SCM and AS muscles from the side of greatest pain as patients performed sustained sub-maximal isometric cervical flexion contractions at 25% and 50% of the maximum voluntary contraction (MVC). The initial value and slope of the mean frequency (MNF), average rectified value (ARV) and conduction velocity (CV) of the EMG signals were calculated. Correlation analysis was applied to determine whether a relationship existed between the duration of neck pain and estimates of EMG variables.
No significant correlation was found between duration of pain and estimates of the MNF, ARV and CV for either SCM or AS contracting at 25% and 50% MVC. The length of history of neck pain does not appear to correlate with the extent of SCM and AS muscle fatigability in patients with chronic neck pain. This finding may be due to an increase of muscle fatigability occurring within the first few years of neck pain, which is not followed by signs of increased fatigue after this time. This was supported by the finding of significant correlations between duration of pain and AS fatigability on a subgroup of patients with pain duration less than 5 years. Future studies are warranted to examine how early signs of cervical muscle fatigability are evident after the onset of neck pain as this will have implications for rehabilitation.
尽管有证据表明颈部疼痛患者的颈浅屈肌更容易疲劳，但颈痛持续时间与肌肉疲劳之间的关系尚未得到研究。本研究在一组慢性颈痛患者中，探讨胸锁乳突肌（SCM）和前斜角肌（AS）肌肉疲劳的肌电表现与颈痛持续时间之间的关系。
20例有1至25年疼痛史（平均6.15年，标准差5.48年）的慢性颈痛患者参与了本研究。当患者以最大自主收缩（MVC）的25%和50%进行持续次最大等长颈部屈曲收缩时，从疼痛最严重一侧的SCM和AS肌肉记录肌电信号。计算肌电信号平均频率（MNF）、平均整流值（ARV）和传导速度（CV）的初始值和斜率。应用相关分析来确定颈痛持续时间与肌电变量估计值之间是否存在关系。
对于在25%和50%MVC收缩的SCM或AS，疼痛持续时间与MNF、ARV和CV的估计值之间未发现显著相关性。在慢性颈痛患者中，颈痛病史的长短似乎与SCM和AS肌肉疲劳程度无关。这一发现可能是由于在颈痛的最初几年内肌肉疲劳增加，而在此之后没有疲劳增加的迹象。疼痛持续时间小于5年的患者亚组中疼痛持续时间与AS疲劳之间存在显著相关性，这一发现支持了上述观点。有必要进行进一步研究，以探讨颈部疼痛发作后颈部肌肉疲劳的早期迹象如何显现，因为这将对康复产生影响。
