Accuracy of Base of Support Using an Inertial Sensor Based Motion Capture System

Area of Science:

• Biomechanics
• Human Movement Analysis
• Wearable Sensor Technology

Background:

• Miniature inertial sensors are increasingly used for human balance and gait analysis.
• Base of Support (BOS) and its interaction with the Center of Mass are critical metrics in these fields.

Purpose of the Study:

• To evaluate the accuracy of the Xsens MVN BIOMECH system for measuring static Base of Support (BOS).
• To examine how task complexity, specifically knee flexion, affects the accuracy of BOS measurements.

Main Methods:

• Eleven healthy young males performed eleven experimental tasks.
• Static BOS measurements were taken using the Xsens MVN BIOMECH system and compared to ground truth.
• Accuracy was assessed across varying levels of knee flexion and task complexity.

Main Results:

• Considerable errors were observed in BOS area estimation ( -12.6% to +64.6%) using the Xsens MVN system.
• Foot separation distance errors were significant, particularly during knee flexion.
• BOS area estimation was smaller than ground truth without knee flexion and larger with knee flexion, increasing with knee flexion angles.

Conclusions:

• The Xsens MVN BIOMECH system exhibits significant errors in estimating BOS area and foot separation, especially with knee flexion.
• Knee flexion and initial system estimation errors are primary contributors to BOS estimation inaccuracies.
• Users should exercise caution when employing Xsens MVN BIOMECH for BOS and foot position measurements, particularly in tasks involving knee flexion.