Exploring the role of heel pad thickness in lower limb biomechanics and plantar pressure during running.

Abstract

Background: While the plantar fat pad is known for its role in shock absorption and plantar force distribution during weight-bearing activities, its impact on running biomechanics is not well understood.

Research question: Does plantar fat pad thickness affect lower limb biomechanics and plantar pressure distribution during running in healthy adults?

Methods: This cross-sectional observational study involved fourteen participants (18-50 years) who ran at their preferred speed on a 10-meter walkway while lower limb kinematics and ground reaction forces were recorded using a motion capture system. Plantar pressure and force on the right foot were measured using a pressure platform. Magnetic Resonance Imaging of the right foot was performed with participants in a supine position with the ankle in a neutral position to assess plantar fat pad thickness. The collected measures included fat pad thickness, peak plantar pressure, peak plantar force, and lower limb joint kinetics and kinematics during running.

Results: Correlation analysis revealed a moderate negative correlation (R²=0.446) between heel fat pad thickness and peak plantarflexion torque during the stance phase of running. Additionally, a thicker plantar fat pad was associated with increased peak plantar pressure (R²=0.422) and peak force (R²=0.031, R²=0.432) under the mid-forefoot region.

Significance: A thicker heel fat pad was found to reduce peak plantarflexion torque, while a thicker overall plantar fat pad was associated with increased peak plantar pressure and force under the mid-forefoot. These results suggest that variations in plantar fat pad thickness may influence ankle biomechanics and plantar pressure distribution, potentially affecting running mechanics.