Stiffness Effects in Rocker-Soled Shoes: Biomechanical Implications

Area of Science:

• Biomechanics
• Footwear Design
• Human Gait Analysis

Background:

• Rocker-soled shoes are designed to alter gait mechanics and reduce stress.
• Understanding the impact of sole material and design on plantar forces is crucial for footwear innovation.

Purpose of the Study:

• To investigate the effects of two rocker sole designs (soft vs. dense material) on plantar forces and spatio-temporal gait variables.
• To compare rocker-soled shoes with barefoot and flat-soled shoe conditions during walking and jogging.

Main Methods:

• Gait parameters of eleven subjects were recorded while walking and jogging.
• Plantar forces and spatio-temporal variables were measured across different footwear conditions: barefoot, flat-soled shoes, soft-material rocker shoes, and dense-material rocker shoes.

Main Results:

• Rocker shoes, particularly those with softer soles, significantly reduced plantar forces during walking compared to barefoot and flat shoes.
• During jogging, plantar forces generally increased across all shoe types compared to barefoot, with softer rocker soles showing higher forces than denser ones.
• The rolling mechanism of rocker soles and increased ankle rotation contribute to force reduction by converting vertical to rotational kinetic energy.

Conclusions:

• Rocker-soled shoe designs can effectively reduce plantar force through specific rolling mechanisms and material stiffness.
• Locomotion speed and sole stiffness are key factors influencing the effectiveness of rocker shoes in managing plantar forces and shock absorption.
• Optimizing rocker shoe design requires balancing force reduction benefits with shock absorption capabilities at various speeds.