Does the Heel's Dissipative Energetic Behavior Affect Its Thermodynamic Responses During Walking?

Area of Science:

• Biomechanics
• Human Locomotion
• Thermodynamics

Background:

• Terrestrial locomotion, like human walking, involves energy dissipation during ground impact.
• The heel performs net-negative work during collisions, but the energy dissipation mechanism remains unclear.
• Understanding heel energy dissipation is crucial for insights into foot thermoregulation and potential complications.

Purpose of the Study:

• To investigate the relationship between energy dissipation and thermal responses in the human heel during walking.
• To determine if increased collisional forces in the heel correlate with temperature changes.
• To explore the implications for foot thermoregulation and tissue integrity.

Main Methods:

• Twenty healthy adults walked overground and on a treadmill at a constant speed.
• Added mass (+0%, +15%, +30% body mass) was applied via a vest to increase heel collisional forces.
• Heel work was estimated using deformable segment analysis, and heel temperature was measured before and after treadmill trials.

Main Results:

• Walking with +30% added mass significantly increased heel temperature change (p=0.009) and net-negative work (p=0.005).
• No significant correlation was found between the heel's net-negative work and temperature changes (p=0.277).
• Findings suggest that heat dissipation mechanisms, not solely direct correlation with negative work, regulate heel temperature.

Conclusions:

• The human heel exhibits dynamic thermoregulatory capacity, preventing excessive temperature rise during locomotion.
• Energy dissipation during heel impact does not directly correlate with temperature increase, indicating complex heat management.
• Further research should explore mechanical and physiological factors influencing heel thermodynamic responses.