Horizontal versus vertical clearance: implications for performance and postural risk in constrained manual...

Area of Science:

• Ergonomics
• Human Factors Engineering
• Occupational Safety

Background:

• Limited empirical data exists on workspace clearance dimensions affecting manual task outcomes and worker posture.
• Spatial design is crucial for workplace ergonomics, yet specific clearance effects are understudied.

Purpose of the Study:

• To investigate the impact of horizontal and vertical workspace clearances on manual assembly task cycle time, error rates, and worker posture.
• To provide evidence-based recommendations for optimizing workspace dimensions in ergonomic design.

Main Methods:

• A within-subject repeated-measures design with 12 participants performing a simulated assembly task.
• Manipulation of horizontal and vertical clearance dimensions.
• Measurement of cycle time, error count, and postural behaviors (shoulder elevation, arm adduction).

Main Results:

• Reduced horizontal clearance significantly increased task cycle time (p < 0.001).
• Vertical clearance did not significantly affect cycle time.
• Neither clearance dimension significantly impacted assembly error rates (p = 0.628).
• Limited horizontal clearance led to compensatory postures, particularly with restricted vertical clearance.

Conclusions:

• Optimizing horizontal clearance (minimum 450 mm) is essential for enhancing manual task efficiency.
• Managing vertical clearance is important for mitigating ergonomic risks in constrained workspaces.
• Findings inform the design of more efficient and safer work environments.