Comparative Analysis of Inertial Sensor to Optical Motion Capture System Performance in Push-Pull Exertion Postures

Area of Science:

• Biomechanics
• Human Factors Engineering
• Wearable Technology

Background:

• Posture kinematics are crucial for understanding biomechanical load during physical tasks.
• Inertial sensors (IS) offer a portable alternative to optical motion capture (MC) for assessing posture.
• The accuracy of IS in dynamic, high-demand tasks requires further investigation.

Purpose of the Study:

• To investigate the impact of physical task demand on posture kinematics during a two-handed force exertion task.
• To evaluate the performance of inertial sensors (IS) compared to optical motion capture (MC) under varying task demands.
• To examine potential interactions between IS performance and physical task demand.

Main Methods:

• Laboratory experiment involving 15 male participants performing a two-handed isometric horizontal force exertion task.
• Physical task demand manipulated via vertical handle height, target force magnitude, and force direction.
• Posture kinematics, specifically torso flexion angle, measured using both IS and an optical motion capture (MC) system.

Main Results:

• Lower handle heights and higher target force magnitudes significantly increased torso and pelvic flexion.
• IS-derived torso flexion angle estimates showed no significant difference compared to MC.
• Root mean squared error (RMSE) between IS and MC increased with target force intensity.

Conclusions:

• IS provide reliable estimates of torso flexion kinematics in a two-handed force exertion task.
• Increased physical task demand, particularly higher forces, can amplify measurement error in IS.
• Findings highlight the importance of considering task demand when using IS for biomechanical assessments.