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Effect of ship motion on spinal loading during manual lifting
Gert S Faber1, Idsart Kingma, Nico J Delleman
1Research Institute MOVE, Faculty of Human Movement Sciences, VU University Amsterdam, The Netherlands.
Ergonomics
|September 20, 2008
Summary
Ship motion significantly increases spinal loading during lifting tasks at sea. Researchers found that increased vertical ship acceleration directly correlated with higher spinal moments and compression forces, regardless of lifting pace.
Area of Science:
- Occupational health
- Biomechanics
- Maritime safety
Background:
- Lifting tasks are common in maritime environments.
- Ship motion introduces dynamic challenges to physical tasks.
- Understanding spinal loading during maritime lifting is crucial for injury prevention.
Purpose of the Study:
- To quantify the impact of ship motion on spinal loading during lifting.
- To determine if workers adjust lifting timing to mitigate spinal load under ship motion.
- To analyze the relationship between vertical ship acceleration and spinal forces.
Main Methods:
- Subjects performed 18 kg box lifts on a ship at sea under various sailing conditions.
- Measurements included ship motion, whole-body kinematics, ground reaction forces, and electromyography.
- Spinal moments and compression forces were calculated.
- Lifting was performed at both free and constrained (10-second intervals) paces.
Main Results:
- Increased vertical ship acceleration led to higher peak spinal moments and compression forces.
- No significant difference in the effect of ship motion on spinal loading was observed between free and constrained lifting paces.
- The findings indicate that workers do not effectively time their lifts to reduce spinal loading under dynamic ship motion.
Conclusions:
- Ship motion, specifically vertical acceleration, directly exacerbates spinal loading during lifting.
- Current lifting strategies do not appear to mitigate the biomechanical risks associated with ship motion.
- Further research into ergonomic interventions for maritime lifting is warranted to reduce occupational back injuries.
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