Using horizontal heel displacement to identify heel strike instants in normal gait

Area of Science:

• Biomechanics
• Gait Analysis
• Kinesiology

Background:

• Heel strike instants are critical for gait analysis but difficult to detect accurately without force plates.
• Existing methods for kinematic heel strike instant (kHSI) detection have limitations.

Purpose of the Study:

• To introduce and validate two novel techniques for kHSI detection using maximal resultant horizontal heel displacement (HHD).
• To compare the accuracy of the proposed HHD techniques against established methods and a force plate threshold.

Main Methods:

• Two new HHD techniques were developed, calculating displacement from stance ankle/heel to the swing heel.
• Techniques were validated against a 10N force plate threshold in 54 healthy adults walking at normal and fast speeds.
• True and absolute errors were calculated for 8678 kHSI events.

Main Results:

• The novel HHD techniques, particularly using the stance ankle as a reference, achieved low true (3.2ms) and absolute (5.7ms) errors.
• These new methods significantly outperformed previously established techniques (p<0.0001).
• Gait speed significantly affected kHSI detection across all evaluated methods (p<0.0001).

Conclusions:

• Novel kinematic heel strike instant detection methods based on horizontal heel displacement offer improved accuracy.
• Referencing the stance ankle for HHD calculations provides superior results compared to other methods.
• Gait speed influences kHSI detection, necessitating condition-specific identification for accurate gait analysis.