Steadiness in one-legged stance: development of a reliable force-platform testing procedure

Area of Science:

• Biomechanics
• Kinesiology
• Human Movement Science

Background:

• Postural steadiness assessment is crucial for evaluating unilateral injuries and disorders.
• Existing test protocols require demonstrated feasibility and reliability for clinical application.

Purpose of the Study:

• To develop and validate a feasible and reliable testing protocol for measuring postural steadiness in a one-legged stance.
• To investigate the within-session retest reliability of the developed protocol in healthy young adults.

Main Methods:

• Developed a force platform-based testing protocol for one-legged stance, with eyes open and closed.
• Collected performance data using standard deviation of orthogonal force components and center of pressure (CP) coordinates.
• Employed strategies to minimize data loss due to balance loss during trials.

Main Results:

• The developed protocol demonstrated substantially improved retest reliability compared to earlier methods.
• Force-based performance scores exhibited higher retest reliability than CP-based scores, a statistically significant finding in some stances.
• Factor analysis indicated that force measures are superior predictors of one-legged stance steadiness.

Conclusions:

• The validated force platform protocol offers a reliable and feasible method for assessing postural steadiness in a one-legged stance.
• This protocol supports the development of clinical and experimental trials using a repeated-measures design with the nonaffected leg as a control.
• Force measures are recommended over CP measures for evaluating postural steadiness due to superior reliability and predictive power.