Comparison of neck muscle activity between healthy & chronic neck pain patients using electromyography

Background and purpose: Chronic neck pain is one of the most common musculoskeletal problems. Generally, around 67% of adults will experience neck pain some time during their life. The aim of this study was to investigate the changes of neck muscles myoelectric activity in patients with chronic neck pain during flexion-extension movement. Materials and methods: This case-control study was conducted on 43 participants, that is, twenty two patients (23± 1.8 years) with chronic neck pain history who were matched against twenty one healthy people (23 ± 2.6 years) with no history of neck pain. They had to accomplish 5 trials of a cervical flexion and extension in sitting position. The electromyoghraphic (EMG) activities of cervical paraspinal and trapezius muscles were bilaterally recorded. To study the difference in muscle strength and range of motion (ROM) between the two groups, cervical ROM and maximum voluntary isometric contraction (MVIC) were also recorded. Data were analyzed using independent t-test and correlation coefficients (ICC). Results: Results of the study showed that EMG activity of cervical erector spine muscles was significantly higher in the patients with chronic neck pain in the first static phase and full flexion one (P≤0.05). However, no significant differences were observed in activity of these muscles in flexion and extension phases (P≥0.05). Moreover, there was no significant difference in the EMG activities of trapezius muscles between the two groups (P≥0.05). The MVIC of cervical paraspinal was significantly higher in the healthy group (P 0.05). Conclusion: Based in the results of the present study it is likely that pain has changed myoelectric activity of cervical muscles. Apparently, the neck extensor muscles should work with more intensity to maintain better control force in the patients with neck pain.