Biomechanical analysis of common solid waste collection throwing techniques using OpenSim and an EMG-assisted solver

Area of Science:

• Occupational biomechanics
• Ergonomics
• Musculoskeletal modeling

Background:

• Solid waste collection is a high-risk occupation for low back pain (LBP).
• Lumbar biomechanical factors like joint reaction forces and moments are key correlates of LBP.

Purpose of the Study:

• To compare LBP risk associated with three waste collection throwing techniques: symmetric (SYM), asymmetric fixed stance (AFS), and asymmetric with pivot (AWP).
• To quantify the influence of object weight (3, 7, 11 kg) on LBP risk factors across different techniques.

Main Methods:

• Utilized a full-body musculoskeletal model in OpenSim to compute lumbar moments and joint reaction loads.
• Employed EMG-assisted and static optimization methods to estimate muscle activations.
• Calculated LBP risk factors based on simulated biomechanical data.

Main Results:

• The EMG-assisted method yielded higher peak compressive and shear forces, indicating greater LBP risk.
• Symmetric techniques showed higher risk for lighter loads (3 kg), while asymmetric techniques posed greater risk for heavier loads (7, 11 kg).
• Increased bag mass consistently elevated LBP risk factors across all techniques.

Conclusions:

• Employ asymmetric techniques for lightweight objects and symmetric techniques for heavier objects to mitigate LBP risk in waste collection.
• Technique choice significantly impacts LBP risk, particularly with varying object weights.
• Further research is needed to clarify risk differences between asymmetric techniques.