Running-related injury prevention through innate impact-moderating behavior

Area of Science:

• Biomechanics
• Human Locomotion
• Foot Anatomy

Background:

• The plantar surface of the foot is crucial for shock absorption during locomotion.
• Understanding localized deformation and pain perception is key to foot protection.
• The Robbins and Hanna hypothesis proposes a link between localized discomfort and protective behaviors.

Purpose of the Study:

• To experimentally test the Robbins and Hanna hypothesis regarding plantar surface sensitivity.
• To quantify the relationship between localized load, pain, and deformation depth on the foot.
• To investigate the mechanisms of protective behavior in intrinsic foot shock absorption.

Main Methods:

• Utilized a penetrometer to apply controlled loads to various plantar surface locations.
• Measured the magnitude of load required to elicit pain and the resulting depth of deformation.
• Analyzed deformation patterns in relation to trabecular tethering of the epithelial membrane.

Main Results:

• Significant variation in pain thresholds across different plantar regions (P < 0.005).
• Higher pain incidence at the first metatarsal-phalangeal joint (66%) compared to the heelpad (6%) and distal first digit (32%) under specific loads.
• Observed distinct deformation patterns consistent with varying degrees of trabecular tethering.

Conclusions:

• The experimental findings support the Robbins and Hanna hypothesis.
• Plantar sensory feedback mechanisms play a vital role in protecting bony structures and ensuring safe locomotion.
• Localized deformation and pain sensitivity are integral to the foot's intrinsic shock absorption capabilities.