The effect of bracing availability on one-hand isometric force exertion capability

Area of Science:

• Biomechanics
• Ergonomics
• Human Factors Engineering

Background:

• Environmental obstructions can limit worker postures but also offer bracing opportunities.
• Reaction forces from bracing can enhance force exertion and are crucial for biomechanical analysis.

Purpose of the Study:

• To quantify the effects of kinematic constraints and bracing on isometric hand force.
• To determine the impact of bracing on maximal force exertion in manual tasks.

Main Methods:

• Laboratory study involving 22 male and female participants.
• Analysis of one-hand maximal push, pull, and lift tasks with and without bracing.
• Quantification of isometric hand force and force direction with available bracing surfaces.

Main Results:

• Bracing surfaces at the thighs and non-task hand enabled an average 43% increase in task hand force.
• Significant deviations in task hand force direction were observed with bracing at various hand locations.

Conclusions:

• Bracing significantly enhances isometric hand force capability in kinematically constrained tasks.
• Understanding bracing effects is critical for accurate ergonomic and biomechanical assessments of manual labor.
• Force direction changes due to bracing have important implications for manual task analysis.