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Flexion-relaxation ratio in neck muscles and chronic neck pain in office workers computer users

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Carina Ferreira Pinheiro
Total Authors: 1
Document type: Master's Dissertation
Press: Ribeirão Preto.
Institution: Universidade de São Paulo (USP). Faculdade de Medicina de Ribeirão Preto (PCARP/BC)
Defense date:
Examining board members:
Marisa de Cássia Registro Fonseca
Advisor: Thais Cristina Chaves

Neck pain is a common musculoskeletal problem, the occurrence of which is estimated at around 30-50% of the adult population in general and also very common among office workers. Activity muscle pattern alterated of flexion and extension muscles is one of the characteristics of neck pain, that office workers is associated with the maintenance of the sitting posture with forward head posture or neck flexion. Two important factor analysis to assess deficits in muscle activation are flexion-relaxation phenomenon (FFR) and the flexor-relaxation ratio (RFR). The aim of this study was to evaluate, using surface electromyography, the occurrence of FFR and measure the RFR in extension neck muscles of office workers with and without chronic neck pain and healthy subjects, not computer users. Sixty subjects were evaluated, 20 office workers with chronic neck pain (GD), 20 office workers without neck pain (GS) and 20 healthy subjects, not computer users (GC). Participants completed the Maastricht Upper Extremity Questionnaire (MUEQ-Br) and Neck Disability Index (IIRP), and the FFR and RFR were analyzed by surface electromyography of the semispinal capitis (SC) splenius capitis (EC) and Upper Trapezius (TS). Pressure pain threshold (PPT) was also evaluated in these muscles and the sternocleidomastoid. Results showed higher scores of the group of workers with chronic neck pain in the workplace domain MUEQ-Br (GS 0.35, 95% CI 0.14 to 0.56; GD 0.80, 95% CI 0.32 to 1 28, p <0.05) and higher EC LDP in the neck pain group compared to control group (GD 1.77, 95% CI 1.55 to 2.00; GC 2.38, 95% CI 2.02 to 2.75; p <0.05). FFR was observed in the same proportion in all groups, not being observed in all subjects. The integral of linear envelope was higher in workers groups than control group in SC at rest posture (GS 0.91, 95% CI 0.90 to 0.93; GD 0.90, 95% CI 0.88 to 0.93 ; GC 0.86, 95% CI 0.83 to 0.90; p <0.05). The relationship between full flexion and extension showed higher SE EMG activity of workers groups in extension compared to control group (GS 0.38, 95% CI from 0.32 to 0.43; GD 0.37, 95% CI 0.30 to 0.44; GC 0.56, 95% CI 0.52 to 0.60; p <0.05). The RFR was higher in the neck pain workers than control group (SG 2.33, 95% CI 1.93 to 2.74; GD 3.10, 95% CI 2.50 to 3.70; GC 1 99, 95% CI 1.81 to 2.17; p <0.05). The test of MVIC of neck extensor muscles showed good to excellent reproducibility, especially in the MVIC and in neck pain group (MVIC GS - ICC SE 0.93; ICC EC 0.57; ICC TS 0.19) (MVIC GD - SC ICC 0.50, EC ICC 0.84, TS ICC 0.96). The results showed that physical factors are related to chronic neck pain disability in office workers. Relations between the EMG activity of the extensor muscles during flexion and extension movements suggest that computer use recruit continuously the extensor muscles, which shows high activity during rest in the neutral position and extent, and remains active during flexion and full flexion. In addition, work computer use, when associated with chronic complaint of neck pain, seems to increase pain sensitivity to pressure on the neck extensor muscles (AU)

FAPESP's process: 12/24138-9 - Flexion-Relaxation Ratio of Cervical Muscles and Chronic Neck Pain in Workers Office Computer Users
Grantee:Carina Ferreira Pinheiro de Araújo
Support type: Scholarships in Brazil - Master