Related Experiment Videos
Trunk muscle electromyography and whole body vibration
R E Seroussi1, D G Wilder, M H Pope
1Department of Orthopaedics and Rehabilitation, University of Vermont, Burlington 05405.
Journal of Biomechanics
|January 1, 1989
Summary
Whole body vibration significantly increases spinal torque compared to static sitting. Electromyography (EMG) of paraspinal muscles revealed higher average and peak torques during vibration across tested frequencies.
Area of Science:
- Biomechanics
- Human Physiology
- Occupational Health
Background:
- Whole body vibration (WBV) is common in occupational settings.
- Understanding spinal loading during WBV is crucial for injury prevention.
- Electromyography (EMG) can estimate muscle activity and infer spinal loads.
Purpose of the Study:
- To quantify spinal torque imposed by WBV.
- To compare spinal torque during WBV versus static seated postures.
- To investigate the frequency-dependent effects of WBV on spinal loading.
Main Methods:
- Surface EMG electrodes were placed on paraspinal muscles (erector spinae at L3).
- Subjects performed isometric pulls to establish an EMG-torque relationship.
- Subjects were exposed to sinusoidal vertical vibration (3-10 Hz, 0.1 g RMS) in a flexed, lordotic seated posture.
- EMG signals were processed using specialized digital techniques to measure torque and its relation to mechanical displacement.
Main Results:
- Significantly higher average spinal torque was observed during WBV compared to static sitting across most tested frequencies.
- Peak-to-peak spinal torque was also significantly elevated during WBV.
- Increased spinal loading was evident from 3 Hz to 10 Hz vibration frequencies.
Conclusions:
- WBV significantly increases the mechanical stress on the spine.
- Paraspinal muscle activity, measured via EMG, is a reliable indicator of spinal torque under vibration.
- Findings highlight potential risks associated with prolonged WBV exposure and inform ergonomic guidelines.