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Published on: January 9, 2016
EMG activity of low back extensor muscles during cyclic flexion/extension
1Department of Industrial and Systems Engineering, University at Buffalo, State University of New York, Buffalo, NY 14260, USA. gshin@buffalo.edu
Summary
Cyclic trunk flexion/extension alters low back muscle activity. Electromyography (EMG) showed delayed muscle re-activation and reduced amplitude during movement, suggesting potential risks for low back pain.
Area of Science:
- Biomechanics
- Musculoskeletal health
- Occupational safety
Background:
- Cyclic trunk flexion/extension is a known risk factor for low back pain.
- In vivo changes in low back musculature from cyclic movements are not well understood.
Purpose of the Study:
- To investigate the effects of cyclic trunk flexion/extension on low back extensor muscle activity.
- To quantify changes in electromyography (EMG) activation timing and mean amplitude.
Main Methods:
- Recorded trunk flexion angle and EMG during 30 cyclic flexion/extension movements over 5 minutes.
- Measured isometric extension EMG before and after cyclic movements.
Main Results:
- Mean EMG in isometric extension increased by 30% post-cyclic movement, indicating tissue load transfer.
- Observed a significant delay in muscle re-activation and decreased mean EMG amplitude during the extension phase of cyclic movements.
Conclusions:
- Cyclic flexion/extension alters low back muscle activation patterns, potentially increasing risk.
- Biomechanical effects are sensitive to task demands, requiring further research into compensatory mechanisms.
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