Postural stabilization by gripping a stick with different force levels.

Area of Science:

• Biomechanics
• Human Motor Control
• Applied Physiology

Background:

• Hand contact with a stationary surface is known to reduce postural sway.
• A mobile support offers a more practical, real-life application for studying stability.
• Grip force is a key variable in understanding the stabilizing effect of external objects.

Purpose of the Study:

• To investigate the effect of gripping a mobile stick on postural stability.
• To determine if grip force level influences the stabilizing effect.
• To assess the applicability of this phenomenon in real-life balance challenges.

Main Methods:

• 18 healthy individuals participated in the study.
• Participants stood in quiet stance, semi-tandem stance, and with eyes closed.
• Postural sway was measured using center of pressure (COP) path length and velocity while gripping a stick with varying forces (1-9N and self-selected).

Main Results:

• Gripping the stick significantly reduced COP path length (up to 23%) and velocity (up to 25%).
• Postural stability improved across all tested grip force levels, including self-selected force.
• The stabilizing effect was observed regardless of the mechanical insufficiency of the applied force.

Conclusions:

• Gripping an external portable object, like a stick, enhances postural stability.
• The benefit to stability is present even with low or self-selected grip forces.
• This finding has practical implications for preventing balance loss in daily life situations.