Reframing Whole-Body Angular Momentum: Exploring the Impact of Low-Pass Filtered Dynamic Local Reference Frames...

Area of Science:

• Biomechanics
• Human Movement Analysis

Background:

• Accurate whole-body angular momentum (WBAM) estimation is crucial for understanding human locomotion.
• Local reference frames aligned with anatomical axes can improve WBAM calculations, especially during complex movements like turning.
• Existing methods may be affected by oscillations in pelvis or center of mass velocity (vCoM) frames.

Purpose of the Study:

• To investigate the impact of different global and local reference frames on WBAM distribution across anatomical axes.
• To compare WBAM component distribution in straight-line walking and turning tasks using pre- and post-filtered local frames.
• To determine the effectiveness of low-pass filtering in standardizing WBAM estimates across various reference frames.

Main Methods:

• Comparison of WBAM component distribution across anteroposterior (AP) and mediolateral (ML) axes.
• Utilized global reference frames and local frames defined by pelvis heading, horizontal vCoM, and average angular velocity (Aω).
• Applied low-pass filtering to local reference frames to mitigate transverse plane oscillations.

Main Results:

• Reference frame choice significantly affected AP and ML WBAM distribution in all tasks.
• The vCoM-oriented local frame showed distinct AP/ML WBAM compared to pelvis and Aω frames before filtering.
• Significant differences in WBAM distribution vanished after applying low-pass filtering to local reference frames.

Conclusions:

• Low-pass filtered local reference frames are essential for precise WBAM estimation in both straight-line and turning activities.
• Pelvis- and vCoM-oriented frames are more practical than Aω-oriented frames for future applications using reduced sensor sets.
• Filtered local frames enhance the applicability of anatomical axes-dependent biomechanical parameters.