Relationship Between Achilles Tendon Thickness, Foot Structure, And Gait Parameters In Healthy Young Adults

PURPOSE: To investigate the associations between Achilles tendon thickness, foot structural characteristics, and spatiotemporal gait parameters in healthy young adults. METHODS: Twenty healthy adults (9 females; age 23.05 ± 3.32 years; height 177.44 ± 12.47 cm) volunteered after providing consent. Achilles tendon thickness was measured via ultrasound imaging at the malleolar level during bilateral stance. Foot structure was assessed via arch index (0.332 ± 0.028) and arch height compliance (0.419 ± 0.159 cm). Gait parameters were collected using a 4.88-meter instrumented walkway during 20 walking trials at self-selected speed, including single support percentage (35.17 ± 1.19%), normalized stride width (0.052 ± 0.015), and normalized stance center of pressure (0.157 ± 0.007). Pearson correlations examined relationships between variables (α = 0.05). RESULTS: Achilles tendon thickness (0.438 ± 0.071 cm) showed a significant negative correlation with normalized stance COP (r = -0.515, p = 0.020). Arch compliance demonstrated a moderate negative correlation with the arch index (r = -0.392, p = 0.087). Normalized stride width was significantly correlated with a single support percentage (r = -0.496, p = 0.026). Achilles thickness showed no significant correlations with arch parameters (r = -0.051 to 0.076, p > 0.05). CONCLUSIONS: The significant relationship between Achilles thickness and stance COP suggests that tendon morphology may influence dynamic foot function during gait. The moderate negative correlation between arch compliance and arch index indicates potential mechanical coupling between static and dynamic foot structure characteristics. These findings provide novel insights into the relationship between ankle-foot morphology and locomotor function, with implications for understanding foot biomechanics in athletic populations.