Student Research Committee, Department of Physiotherapy, School of Rehabilitation, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
Physiotherapy Research Centre, School of Rehabilitation, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
J Back Musculoskelet Rehabil. 2021;34(3):461-468. doi: 10.3233/BMR-200137.
The cervical flexion relaxation phenomenon (FRP) is a myoelectric silence of neck extensor muscles which occurs after a certain degree of flexion. Impaired flexion relaxation can impose the vertebral structures to excessive loading resulting from the persistence of muscular contraction.
This study aimed to investigate the incidence or absence of FRP in cervical erector spinae (CES) and upper trapezius muscles in patients with chronic neck pain (CNP).
Twenty-five patients with CNP and 25 healthy volunteers were recruited. They accomplished cervical flexion and extension from a neutral position in four phases in the sitting position. The surface electromyography activity of both CES and upper trapezius muscles was recorded in each phase. Cervical flexion and extension movements were simultaneously measured using an electrogoniometer.
FRP in CES was observed in 84% and 36% of healthy subjects and CNP patients, respectively. Flexion relaxation ratio (FRR) in CES was lower in CNP patients than in healthy subjects (mean diff = 1.33; 95% CI: 0.75-1.91) (P< 0.001). Only in CNP patients, FRR in right erector spinea was significantly higher than that in the left erector spinea (P= 0.04).
FRP incidence in CNP patients was less than in healthy subjects. Moreover, this phenomenon begins later in CNP patients than in healthy subjects indicating prolonged activity of CES muscles during flexion in the CNP group. The difference between FRR in the right and left sides of erector spinea muscles can result in CNP.
颈椎屈伸放松现象（FRP）是颈部伸肌在一定程度弯曲后出现的肌电静止现象。屈伸放松受损会使椎体结构承受过度的负荷，导致肌肉持续收缩。
本研究旨在调查慢性颈痛（CNP）患者颈椎伸肌（CES）和上斜方肌是否存在 FRP。
招募了 25 名 CNP 患者和 25 名健康志愿者。他们在坐姿下从中立位进行颈椎前屈和后伸运动，共分四个阶段。在每个阶段记录 CES 和上斜方肌的表面肌电图活动。使用电子角度计同时测量颈椎前屈和后伸运动。
CES 中的 FRP 在健康受试者和 CNP 患者中分别观察到 84%和 36%。CES 的屈伸比（FRR）在 CNP 患者中低于健康受试者（平均差异=1.33；95%CI：0.75-1.91）（P<0.001）。只有在 CNP 患者中，右侧竖脊肌的 FRR 明显高于左侧（P=0.04）。
CNP 患者的 FRP 发生率低于健康受试者。此外，这种现象在 CNP 患者中出现得更晚，表明 CNP 组在弯曲过程中 CES 肌肉的活动时间延长。竖脊肌左右侧 FRR 的差异可能导致 CNP。
