Deformations in the Shoulder Tissues During Load Carriage: A Computational Model.

Area of Science:

• Biomechanics
• Human Factors Engineering
• Medical Imaging

Background:

• Shoulder soft tissue deformation limits load carriage capacity for soldiers and backpackers.
• Current backpack designs lack consistent pressure relief for the shoulder region.
• No established loading limits exist for shoulder forces during load carriage.

Purpose of the Study:

• To develop a biomechanical model for studying shoulder loads under heavy conditions.
• To aid in optimizing load carriage systems design.
• To analyze superficial and inner tissue deformations in the shoulder.

Main Methods:

• Construction of a 3D, anatomically accurate finite element model of the human shoulder based on MRI scans.
• Calculation of effective stresses on skin and effective strain in the brachial plexus region for loads up to 35 kg.
• Validation of the model against deformations measured from load-bearing MRI scans.

Main Results:

• The model accurately predicted soft tissue deformations around the brachial plexus.
• Skin pressure mapping identified pressure hotspots, particularly in the clavicle region.
• Peak inner tissue deformations reached 30% effective strain in the lateral shoulder aspect.

Conclusions:

• The developed finite element model effectively predicts shoulder soft tissue deformations caused by backpacks.
• This model offers a tool for optimizing load carriage systems.
• Future applications include improving pressure distribution and reducing inner tissue deformation.