Dynamic Changes of Longitudinal Arch Work Are Related to Energy Expenditure During Long-Distance Running

The medial longitudinal arch of the foot plays a role in energy storage and release during running; however, the relationship between its dynamic mechanical behavior and energy expenditure remains poorly understood. This study aimed to investigate the association between changes in the mechanical work of the longitudinal arch and the energy expenditure during prolonged running.

16 male athletes or sports enthusiasts participated in a 60-min treadmill running trial at a constant speed of 10 km/h. Biomechanical data were obtained using force-instrumented treadmill and a motion capture system to compute the positive and negative work of the longitudinal arch. Metabolic data, including oxygen consumption (VO₂), carbon dioxide production (VCO₂), and heart rate (HR), were simultaneously measured with a Cortex cardiopulmonary function tester.

Positive arch work and metabolic variables increased rapidly during the first 10 min and then stabilized, with inflection points consistently observed at the 10-min mark (p < 0.001). In contrast, no significant main effect of time was found for negative arch work (p = 0.058). Both positive and negative arch work showed significant positive correlations with energy expenditure (positive work: r = 0.588, p = 0.017; negative work: r = 0.514, p = 0.042), indicating that the dynamic function of the longitudinal arch is linked to metabolic demand, especially when adapting to exercise intensity.

These findings highlight the critical mechanical role of the foot's longitudinal arch and surrounding soft tissues in regulating energy expenditure during running. Strengthening the longitudinal arch and implementing timely stretching may help improve running efficiency by optimizing energy utilization.