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Effects of work surface and task difficulty on neck-shoulder posture and trapezius activity during a simulated mouse
Josiane Sotrate Gonçalves1, Cristiane Shinohara Moriguchi1, Karina Satiko Takekawa1
1a Department of Physical Therapy , Federal University of São Carlos , Brazil.
International Journal of Occupational Safety and Ergonomics : JOSE
|February 10, 2018
Summary
Work surface height and task difficulty significantly impact head and upper back posture during computer mouse tasks. Table height primarily affects upper arm position and trapezius muscle activity.
Area of Science:
- Ergonomics
- Occupational Health
- Biomechanics
Background:
- Poor workstation ergonomics can lead to musculoskeletal discomfort.
- Understanding posture and muscle activity is crucial for preventing injuries.
Purpose of the Study:
- To assess how work surface height and task difficulty affect head, upper back, and upper arm postures.
- To evaluate the influence on descending trapezius muscle activity during a simulated mouse task.
Main Methods:
- 15 healthy female university students participated.
- Work surface height was set at elbow height (EH) and above elbow height (AEH).
- Task difficulty was varied between low (LD) and high (HD) levels, with posture measured by inclinometers and muscle activity normalized to maximum voluntary isometric contraction (MVIC).
Main Results:
- Higher head flexion occurred at EH versus AEH (2°-5° difference).
- High difficulty (HD) tasks increased head (3°-6°) and upper back flexion (6°-7°).
- Above elbow height (AEH) resulted in greater upper arm elevation (6°-8°) and trapezius activity (0.8-1.4% MVIC) irrespective of task difficulty.
Conclusions:
- Head posture is affected by both table height and task difficulty.
- Upper back posture is influenced by high task difficulty.
- Upper arm posture and trapezius muscle activity are solely dependent on work surface height.
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