Psychophysical basis for maximum pushing and pulling forces: A review and recommendations

Area of Science:

• Ergonomics
• Occupational Health
• Biomechanics

Background:

• Manual handling tasks, including pushing and pulling, are common in workplaces.
• Determining safe force limits is crucial for preventing musculoskeletal injuries.
• Previous research established guidelines for maximum acceptable forces.

Purpose of the Study:

• To comprehensively review psychophysically determined maximum acceptable pushing and pulling forces.
• To identify and discuss factors influencing these forces.
• To compare findings from different measurement methods and update recommendations.

Main Methods:

• Literature review of psychophysical studies on pushing and pulling forces.
• Analysis of factors affecting force exertion (e.g., handle height, frequency, distance).
• Comparison of forces measured on treadmills versus high inertia carts.

Main Results:

• Recent studies indicate decreased maximum acceptable forces for males on treadmills, but not females.
• High inertia carts yield higher pushing/pulling forces for males compared to treadmills.
• Snook and Ciriello's (1991) recommendations are still considered valid and practical.

Conclusions:

• Existing recommendations for pushing and pulling forces are appropriate for ergonomics practitioners.
• Regression equations are provided for estimating forces acceptable to 75% of workers.
• Further epidemiological studies are needed to link psychophysical forces to musculoskeletal injury risk.