On the filtering of intersegmental loads during running

Area of Science:

• Biomechanics
• Kinetics
• Data Processing

Background:

• Traditional inverse dynamics analysis often uses data smoothing that introduces artifacts in joint moments during impulsive activities.
• These artifacts, resembling impacts, can obscure true joint loading patterns, particularly in activities like running.

Purpose of the Study:

• To present and validate a novel processing technique for inverse dynamics analysis.
• To demonstrate how this technique mitigates impact artifacts in joint moments and preserves joint reaction forces.

Main Methods:

• Performing inverse dynamics analysis on raw kinematic and force platform data.
• Subsequent smoothing of joint reaction forces and moments based on the frequency content of the distal reaction force.
• Validation using forward dynamics simulations and experimental data from 10 subjects running at various speeds.

Main Results:

• The proposed technique effectively avoids impact artifacts in joint moments.
• Minimal attenuation of joint reaction forces was observed with the new method.
• Artifacts from traditional filtering were systematic, speed-dependent, and most prominent at the hip.

Conclusions:

• Processing raw data and subsequently smoothing intersegmental loads is a superior method for inverse dynamics analysis.
• This approach enhances the accuracy of joint moment calculations, especially during dynamic activities.
• The findings have significant implications for accurately assessing joint loading in biomechanical research.