A comparative investigation of flexion relaxation phenomenon in healthy and chronic neck pain subjects

• Published in: European spine journal 2013-01, Vol.22 (1), p.162-168
• Main Authors: Maroufi, Nader, Ahmadi, Amir, Mousavi Khatir, Seyedeh Roghayeh
• Format: Article
• Language: English
• Subjects: Biomechanical Phenomena; Cervical Vertebrae; Electromyography; EMG; Female; Humans; Low back pain; Medicine; Medicine & Public Health; Movement - physiology; Muscles; Neck; Neck Muscles - physiopathology; Neck Pain - physiopathology; Neurosurgery; Original; Original Article; Pain; Range of Motion, Articular - physiology; Spine (lumbar); Surgical Orthopedics; Young Adult
• ISSN: 0940-6719; 1432-0932
• DOI: 10.1007/s00586-012-2517-3

Purpose The cervical flexion relaxation phenomenon (FRP) is a neck extensor myoelectric “silence” that occurs during complete cervical and lumbar flexion. In contrast to low back pain, the changes that occur during FRP in chronic neck pain (CNP) patients are still not clear. The aim of this study was to assess the characteristics of this phenomenon in the cervical region in CNP patients and controls. Methods Twenty-two women (23 ± 2.62 years) with chronic non-specific neck pain and 21 healthy women (23.4 ± 1.68 years) participated in this study. They accomplished a cervical flexion and extension from neutral position. Neck angle and surface electromyographic activity of cervical erector spinae (CES) and upper trapezius muscles were recorded. Appearance, onset and offset angle of the FRP were analysed and compared between the two groups. Results There were significant differences in the appearance of FRP between the two groups ( P  ≤ 0.001). The FRP in the CES muscles was observed in 85.7 % of healthy subjects and in 36.3 % of CNP patients, and no FRP was observed in the upper trapezius. Results of this study show that the onset and offset of FRP parameters were significantly different between the two groups ( P  ≤ 0.001). Conclusions The results of the present study indicate that FRP in CNP patients was seen less than the healthy subjects, and moreover the FRP period was reduced in CNP patients. Our results also suggest that the changes in FRP of CNP patients may be due to the increased CES activity in these patients.