Validation of Pelvis and Trunk Range of Motion as Assessed Using Inertial Measurement Units

Area of Science:

• Biomechanics
• Human Movement Analysis
• Wearable Technology

Background:

• Trunk and pelvis range of motion (ROM) is crucial for daily activities.
• Aging and neuromusculoskeletal disorders can limit ROM.
• Inertial measurement units (IMUs) are emerging tools for motion assessment.

Purpose of the Study:

• To evaluate the accuracy and reliability of IMU-based trunk and pelvis ROM measurements during gait.
• To compare IMU system (Opal APDM 6 sensor, Mobility Lab 4 software) performance against a gold-standard optoelectric motion capture system.

Main Methods:

• Thirteen healthy young adults participated in the study.
• Trunk and pelvis ROM were measured using IMUs and an optoelectric system during steady-state gait.
• A head-to-head comparison used IMUs mounted on the sternum and sacrum.

Main Results:

• IMU measurements for trunk ROM were within 5-7 degrees of the motion capture system across all planes.
• Pelvis ROM measurements using IMUs were within 10 degrees of the gold standard.
• IMU measurements showed good agreement (within 5-10 degrees) with the triad marker comparison.
• Greater variability was observed in pelvis transverse plane ROM measurements.

Conclusions:

• IMUs and associated software provide valid and reliable measurements of trunk and pelvis ROM in healthy individuals.
• This technology presents a viable option for future clinical and research applications in mobility assessment.