A method for quantifying directional strength and motor control of the trunk

Area of Science:

• Biomechanics
• Motor Control
• Rehabilitation Engineering

Background:

• Trunk motor control is crucial for daily activities and rehabilitation.
• Accurate measurement of trunk forces is essential for assessing motor control deficits.

Purpose of the Study:

• To introduce and validate a novel apparatus for measuring trunk motor control.
• To assess the accuracy and reproducibility of the new measurement system.

Main Methods:

• Developed a new apparatus to exert and measure quasi-isometric trunk forces in any horizontal direction.
• Utilized a novel transducing system for trunk force measurement and three force plates for reaction force measurement.
• Tested 24 healthy subjects exerting maximal forces in eight directions, with and without pelvis fixation.

Main Results:

• The apparatus demonstrated high accuracy, with a small mean bias (-3.0 N for magnitude, 0.72 degrees for direction).
• The system detected significant effects of movement direction and pelvis fixation on maximal force.
• Measurements were reproducible across different sessions, indicating reliability.

Conclusions:

• The new device enables accurate measurement of static and dynamic trunk forces in multiple directions while seated.
• The system provides reproducible data suitable for longitudinal studies and quantifying motor control deficits/recovery.
• This method is valuable for assessing trunk motor control in neurological conditions.