Protocol for the omnidirectional assessment of manual strength

Area of Science:

• Biomechanics
• Human Factors Engineering
• Ergonomics

Background:

• Assessing three-dimensional (3D) manual strength is crucial for understanding human capabilities in various environments.
• Existing methods often lack comprehensive assessment across all force directions and heights.
• Standardized protocols are needed for reliable and valid strength measurements.

Purpose of the Study:

• To present and validate a novel protocol for assessing manual strength in three dimensions.
• To determine the reliability and validity of the proposed assessment method.
• To investigate the influence of hand height on 3D manual strength patterns.

Main Methods:

• Developed a protocol for maximal one-handed exertions across the entire sphere of force application.
• Tested the protocol on four male subjects at two hand heights (1.0 m and 1.75 m) and a fixed foot distance (0.5 m).
• Utilized multiple testing sessions with controlled data collection periods and rest intervals to ensure reliability.

Main Results:

• The protocol demonstrated high reliability for measuring 3D forces, with a correlation coefficient (r) of 0.96 at 1.0 m hand height.
• The methodology proved suitable for assessing 3D manual strength at both 1.0 m and 1.75 m hand heights.
• Distinct force patterns were observed at different hand heights, emphasizing the significant effect of height on manual strength.

Conclusions:

• The presented protocol offers a reliable and valid method for assessing 3D manual strength.
• The findings underscore the importance of hand height in modulating human strength output in all directions.
• This methodology provides a foundation for future clinical and scientific research on human strength capabilities.