Maximum acceptable forces of dynamic pushing: comparison of two techniques

Area of Science:

• Ergonomics
• Occupational Health
• Human Factors Engineering

Background:

• Assessing acceptable forces in industrial tasks is crucial for preventing musculoskeletal injuries.
• Existing ergonomic data, such as Snook and Ciriello's (1991) pushing and pulling data bank, informs workplace design.
• Understanding force exertion differences between various equipment types is essential for accurate risk assessment.

Purpose of the Study:

• To determine the maximum acceptable initial and sustained pushing forces for industrial workers.
• To compare force exertion on a high-inertia push-cart versus a magnetic particle brake treadmill.
• To evaluate the psychophysical tolerance of workers during prolonged pushing tasks.

Main Methods:

• A psychophysical methodology was utilized, asking participants to self-select sustainable workloads.
• Eight male industrial workers performed standardized pushing tasks.
• Tasks included a 40-minute treadmill session and two 2-hour push-cart sessions with a novel water loading system.

Main Results:

• Maximum acceptable initial pushing forces were 28% higher on the high-inertia cart compared to the treadmill.
• Maximum acceptable sustained pushing forces were 23% higher on the high-inertia cart compared to the treadmill.
• Workers reported sustainable workloads without undue strain, fatigue, or physiological distress.

Conclusions:

• The high-inertia push-cart allows for significantly greater acceptable pushing forces than the magnetic particle brake treadmill.
• Current ergonomic guidelines for pushing and pulling may require revision based on these findings.
• Further research is recommended to validate these results and inform updated safety standards.