The within-day and between-day reliability of using sacral accelerations to quantify balance performance

Area of Science:

• Biomechanics
• Kinesiology
• Wearable Technology

Background:

• Balance is crucial for daily activities and injury prevention.
• Objective balance assessment is needed for clinical and research settings.
• Wearable accelerometers offer a portable solution for balance analysis.

Purpose of the Study:

• To assess the reliability of a sacral mounted accelerometer for balance performance.
• To compare different balance metrics derived from accelerometer data.
• To determine the within-day and between-day reliability of these metrics.

Main Methods:

• Experimental, cross-sectional study with 30 healthy volunteers.
• Participants performed static balance tasks (double leg, tandem, single leg stance) with eyes open/closed.
• Acceleration data converted to path length (PL), jerk, and root mean square (RMS).

Main Results:

• Path length (PL) demonstrated excellent within-day (ICC=0.78) and good between-day (ICC=0.61) reliability.
• Minimal detectable change for PL was small (within-day 6.7%, between-day 6.1%).
• PL showed the highest discriminatory value across the tested balance tasks.

Conclusions:

• Sacral mounted accelerometers provide reliable balance performance measures.
• Path length (PL) is the preferred metric due to superior reliability, discrimination, and sensitivity.
• This technology can be utilized for objective balance assessment in various populations.