Postural stability measures: what to measure and for how long

Area of Science:

• Biomechanics
• Human Movement Science
• Clinical Measurement

Background:

• Postural stability assessment is crucial for identifying sensorimotor deficits.
• Force plate analysis offers objective postural stability measurements.
• Understanding the repeatability of these measurements is essential for clinical validity.

Purpose of the Study:

• To assess the repeatability of force plate postural stability measurements.
• To investigate the influence of test duration, vision, and stance conditions on reliability.
• To determine optimal parameters for reliable postural stability assessment.

Main Methods:

• Evaluated common force plate parameters across five test durations.
• Included two vision conditions (eyes open/closed) and two stance conditions (feet together/apart).
• Analyzed test-retest reliability for all parameters under varying conditions.

Main Results:

• All investigated force plate parameters demonstrated reliable measurements.
• Optimal test-retest reliability was achieved with 20-s and 30-s trial periods.
• Centre of pressure measures increased with duration, while ground reaction forces and velocity slightly decreased.

Conclusions:

• Force plate measures of center of pressure and ground reaction forces are clinically useful for detecting and quantifying postural deficiencies.
• Test duration significantly impacts the reliability and validity of postural stability measures.
• These findings support the clinical application of force plate analysis in assessing sensorimotor function.