Long-distance running induces dynamic arch collapse, leading to abnormal plantar pressure distribution and increased injury risk. This study systematically investigated the effects of 3D-printed arch support insert parameters on biomechanical and subjective outcomes in marathon runners. Forty male runners with normal arches (arch index 0.21 – 0.26) participated in a comprehensive testing protocol. Twenty-four insert variants combining six support heights (3 – 18 mm) and four infill densities (20 – 26%) were fabricated using thermoplastic polyurethane (TPU). Dynamic plantar pressure across ten foot regions, arch morphology (Chippaux-Smirak IndexCSI), and subjective ratings were collected during 5-km running tests at marathon pace using a Footscan pressure plate system (200 Hz sampling frequency). Statistical analysis employed repeated-measures ANOVA with Bonferroni correction (α = 0.05). demonstrated that support heights of 9 – 15 mm significantly reduced peak plantar pressure (PPP) in high-risk regions (hallux, first-second metatarsals, lateral heel) by 8–18% ( P < 0.05) while functionally increasing midfoot loading by 5–8% ( P < 0.05), achieving effective pressure redistribution. The 18 mm height group was excluded due to significant discomfort (VAS pain ≥ 50 mm) and lateral foot over-loading (midfoot pressure increase rate −8.95%). Infill densities of 22 – 26% demonstrated significantly superior pressure-reducing efficacy compared to 20% density ( P < 0.05), attributed to optimal energy absorption characteristics under repetitive impact loading. The CSI showed no significant changes across conditions ( P = 0.574), indicating that functional inserts optimize pressure distribution without altering foot morphology in short-term use. The optimal parameter combination of 9 – 15 mm support height with 22 – 26% infill density effectively balances biomechanical protection and wearing comfort. This study provides quantitative evidence for developing personalized functional footwear capable of preventing running-related injuries in marathon athletes.
Dong et al. (Sun,) studied this question.