Flexion-relaxation ratio in computer workers with and without chronic neck pain
Carina Ferreira Pinheiro1, Marina Foresti dos Santos2, Thais Cristina Chaves3
1Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, São Paulo, Brazil; Post Graduation Program in Rehabilitation and Functional Performance, University of São Paulo, Ribeirão Preto, São Paulo, Brazil.
Summary
Computer work alters cervical extensor muscle activity, indicated by changes in flexion-relaxation ratios (FR-ratios). These ratios may serve as a marker for neck pain and disorders in computer users.
Area of Science:
- Biomedical Engineering
- Neuroscience
- Ergonomics
Background:
- Chronic neck pain is prevalent among computer workers.
- The flexion-relaxation phenomenon (FRP) and its ratios (FR-ratios) reflect neuromuscular control of cervical extensor muscles.
- Understanding these parameters in computer users is crucial for identifying risk factors and developing interventions.
Purpose of the Study:
- To evaluate the flexion-relaxation phenomenon (FRP) and flexion-relaxation ratios (FR-ratios) in the cervical extensor muscles of computer workers with and without chronic neck pain, compared to healthy controls.
- To determine if FR-ratios can serve as a functional predictive neuromuscular marker for neck musculoskeletal disorders.
Main Methods:
- Surface electromyography (sEMG) was used to analyze the cervical extensor muscles in 60 subjects (20-45 years).
- Participants included computer workers with chronic neck pain (CPG), computer workers without neck pain (NPG), and a control group (CG) with minimal computer use.
- Flexion-relaxation ratios (FRR), defined as the ratio of maximum activity during re-extension to activity during full flexion, were calculated.
Main Results:
- FR-ratios were significantly smaller in the semispinalis capitis muscles of both computer worker groups (CPG and NPG) compared to the control group (CG).
- The reference FR-ratio (FRR) was significantly higher in computer workers with neck pain (CPG) compared to controls.
- Altered FR-ratios were observed even in asymptomatic computer workers (NPG), suggesting a potential link to early-stage neuromuscular changes.
Conclusions:
- Computer use may lead to increased recruitment of the semispinalis capitis during neck extension phases.
- FR-ratios of the semispinalis capitis show potential as a functional predictive neuromuscular marker for asymptomatic neck musculoskeletal disorders.
- FRR values demonstrate good discriminative ability for detecting existing neck pain, suggesting distinct applications for different FR-ratios.
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