Low-frequency accelerations over-estimate impact-related shock during walking

Area of Science:

• Biomechanics
• Gait Analysis
• Signal Processing

Background:

• Gait analysis often overlooks the low-frequency component of acceleration signals.
• This oversight can lead to overestimating impact shock and drawing incorrect conclusions.

Purpose of the Study:

• To investigate the significance of the low-frequency component in gait.
• To compare impact shock quantification in barefoot (BF) versus shod (SHOD) walking.

Main Methods:

• Twenty-seven participants completed walking trials in BF and SHOD conditions.
• Acceleration signals from shank and spine were analyzed in time and frequency domains.
• Power spectrum density (PSD) was used to quantify active (low-frequency) and impact-related components.

Main Results:

• Peak positive accelerations (PPA) were higher in BF walking.
• When the low-frequency component was considered, no significant difference in impact-related PSD was found between BF and SHOD conditions.
• Active PSD was significantly higher in BF walking due to kinematic differences.

Conclusions:

• The low-frequency component of gait acceleration signals is influenced by knee and ankle coordination.
• Frequency-domain analysis, after subtracting the low-frequency component, offers a more accurate quantification of impact-related shock.
• This approach is crucial for reliable gait impact assessment.