Abstract: This study investigated acute effects of 10 km running on the foot morphology and plantar pressure distribution of male amateur runners. Three-dimensional foot scanning and plantar pressure analyses were performed for 15 participants before and after 10 km running. Results show that after running, foot dorsal height significantly decreased ((67.53±4.06)mm vs (65.33±3.99) mm, p=0.006) and forefoot width increased ((98.73±3.75)mm vs (99.94±3.73) mm, p=0.024) with no change in foot length/metatarsal parameters (p＞0.05). The structure parameters of foot arch exhibited 7.5% reduction in navicular height ((46.43±4.43)mm vs (42.97±5.50)mm, p＜0.001), 3.8% decline in arch height index ((36.05±2.55) vs (34.67±2.65), p=0.003), and 34.9% increase in navicular height difference ((4.31±1.49)mm vs (5.81±2.22)mm, p=0.048). Plantar pressure redistribution showed 24% elevation at medial first metatarsal region (6.68% vs 8.28%, p=0.017), 21% reduction at lateral fifth metatarsal region (6.09% vs 4.81%, p=0.008), and unchanged loading in other regions (p＞0.05). Morphological alterations correlated with foot pronation tendency. These findings indicate that arch collapse and forefoot expansion after long-distance running may exacerbate abnormal biomechanical loading. We propose redesigning long-distance running shoes with enhanced midfoot containment systems and forefoot width allowance to mitigate injury risks and improve comfort.