Propulsive joint powers track with sensor-derived angular velocity: A potential tool for lab-less gait retraining

Area of Science:

• Biomechanics
• Gerontology
• Wearable Technology

Background:

• Reduced propulsive joint powers, especially at the ankle, are common in older adults compared to younger individuals.
• Current methods for assessing joint powers necessitate specialized laboratory equipment like motion capture and force treadmills.
• There is a need for portable, reliable measures to track changes in joint powers outside of a clinical setting.

Purpose of the Study:

• To investigate the correlation between kinematic data from inertial measurement units (IMUs) and propulsive joint powers calculated via inverse dynamics.
• To assess the feasibility of using wearable sensors for monitoring joint power changes during walking.

Main Methods:

• Simultaneously collected motion capture, force plate, and IMU data from young and older adults walking at various speeds.
• Calculated hip, knee, and ankle joint powers using inverse dynamics, focusing on propulsive peaks in late stance.
• Processed IMU gyroscope data to determine segment and joint angular velocities, correlating these with joint powers.

Main Results:

• Significant correlations were found between hip joint power and hip/thigh angular velocities (r=0.80-0.83).
• Strong correlations were observed between ankle joint power and ankle/shank/foot angular velocities (r=0.77-0.89).
• Correlation strengths were consistent across age groups and between segment/joint angular velocities.

Conclusions:

• Kinematic data from IMUs strongly correlate with propulsive joint powers during walking.
• Wearable IMU sensors offer a viable and portable method for tracking longitudinal changes in joint powers.
• This approach facilitates the translation of gait interventions from laboratory settings to real-world applications.