A mechanical protocol to replicate impact in walking footwear.

Area of Science:

• Biomechanics
• Sports Engineering
• Materials Science

Background:

• Standard impact testing for footwear often uses protocols designed for running, which may not accurately reflect the forces experienced during walking.
• Existing methods may apply excessive energy to walking footwear, potentially leading to inaccurate material property assessments.

Purpose of the Study:

• To modify the ASTM F1614 (Procedure A) mechanical testing protocol to better simulate walking gait.
• To investigate the impact characteristics of different footwear styles during walking.
• To develop a gait-specific mechanical testing protocol for walking footwear.

Main Methods:

• Collected kinematic and kinetic data from participants walking in four footwear types: trainer, oxford shoe, flip-flop, and triple-density sandal.
• Quantified heel velocity and effective mass at ground impact during walking.
• Adapted the ASTM protocol by adjusting mass and drop height based on captured walking data.

Main Results:

• Kinematic data revealed distinct impact characteristics across footwear styles, with faster heel velocities observed in flip-flops and sandals.
• Adapted mechanical protocols, tailored to specific footwear, yielded significantly lower peak force and accelerometer values compared to the standard ASTM protocol.
• The adapted protocol showed a mean difference of 12.7% for peak acceleration and 25.2% for peak force compared to human walking data.

Conclusions:

• Altered mechanical test protocols can more accurately replicate lower limb loading during walking.
• Footwear material testing should be specific to gait style (e.g., running vs. walking) and footwear type.
• This research highlights the need for specialized testing to ensure optimal shock absorption and performance in walking footwear.