A new approach to measure stability during quiet standing

Area of Science:

• Biomechanics
• Human Physiology
• Rehabilitation Science

Background:

• Standing balance is a complex process involving multiple physiological systems.
• Previous studies predominantly analyzed stability using one-minute force plate data.
• Prolonged standing is common in daily activities, yet its stability dynamics remain under-investigated.

Purpose of the Study:

• To investigate postural stability during prolonged quiet standing for five minutes.
• To determine if one-minute assessments accurately reflect overall standing balance.
• To identify optimal periods for stability assessment during extended standing.

Main Methods:

• Forty healthy subjects (students and staff) participated.
• Participants stood on a Kistler force plate for five minutes.
• Center of Pressure (COP) sway was measured in both anterior-posterior and medial-lateral planes.

Main Results:

• One-minute COP sway analysis is not recommended for evaluating standing stability.
• Significant differences in COP excursions were observed across the five-minute trial.
• Peak subject stability occurred during the third and fourth minutes of standing.

Conclusions:

• Initial one-minute COP sway data does not reliably represent overall standing stability.
• Assessing the ability to recover from instability is crucial for a comprehensive stability evaluation.
• Five-minute standing trials provide a more accurate measure of postural control than shorter durations.