Adjustments in Shoulder and Back Kinematics during Repetitive Palletizing Tasks

Area of Science:

• Occupational biomechanics
• Ergonomics
• Musculoskeletal injury prevention

Background:

• Repetitive tasks, particularly lifting, are a primary cause of musculoskeletal injuries in warehouse order-picking workers.
• Existing research often lacks a separate biomechanical analysis of back and shoulder movements during loaded versus unloaded lifting events.

Purpose of the Study:

• To investigate the distinct biomechanics of the back and shoulder during simulated de/palletization tasks.
• To analyze kinematic changes in order-picking workers over multiple task sessions, focusing on loaded lifting events.

Main Methods:

• Utilized an optical motion capture system to record back inclination and shoulder flexion in nine healthy male participants.
• Participants performed three sessions of a simulated de/palletization task.
• Compared kinematic data between the initial and final sessions to identify significant changes.

Main Results:

• Statistically significant changes (p<0.05) were observed in movement timings, angles, back-shoulder coordination, and shoulder moments between the first and last sessions.
• The majority of these significant kinematic alterations occurred during loaded lifting events.
• This highlights the importance of differentiating between loaded and unloaded lifting in biomechanical assessments.

Conclusions:

• Separating the analysis of loaded and unloaded lifting events is crucial for accurate biomechanical assessment in warehouse settings.
• Monitoring kinematic changes specifically during loaded periods can effectively identify potential risks for musculoskeletal injuries in order-picking workers.
• This approach offers a targeted strategy for worker evaluation and injury prevention in the logistics industry.