Biomechanical Correlates between Foot Arch Morphology and Sports Injury Risks: a Multifactorial Analysis of 1078 University Students

Biomechanical Correlates between Foot Arch Morphology and Sports Injury Risks: a Multifactorial Analysis of 1078 University Students | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Article Biomechanical Correlates between Foot Arch Morphology and Sports Injury Risks: a Multifactorial Analysis of 1078 University Students Zhiyi Xu, Yu Lin, Yiquan Chen, Liyuan Yu, Xiangdong Wang, Jinhui Yan This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-7090359/v1 This work is licensed under a CC BY 4.0 License Status: Published Journal Publication published 05 Feb, 2026 Read the published version in Scientific Reports → Version 1 posted 14 You are reading this latest preprint version Abstract Objective: This study aimed to investigate the relationship between foot arch structure and lower limb biomechanical parameters and to quantify the effects of arch morphology on postural stability, plantar pressure distribution, foot elasticity, and related structural deformities. Methods: A cross-sectional study was conducted involving 1078 university students (569 males and 509 females; mean age = 20.18 ± 1.43 years). The iFEET Neo 3D system was used to measure arch height, hallux valgus angle, and calcaneal angle, whereas the iGAIT MAX 3D system assessed plantar pressure distribution, center of gravity displacement, mediolateral pressure center deviation, arch elasticity index (AEI), and pressure recovery rate (PRR). A Kistler force platform (Model 9286B) was used to calculate the coordination asymmetry index (CAI) and the Hurst exponent of the center of pressure trajectory. Multivariate linear regression and mixed-effects models were employed to examine the associations between foot arch type and the measured biomechanical parameters. Results: Arch height demonstrated significant association with multiple biomechanical indicators. Individuals with high arches exhibited a marked increase in hallux valgus angle ( B = 35.303, P < 0.001), and each 1 mm decrease in arch height was associated with a 2.45° increase in calcaneal eversion ( B = –2.447, R ² = 0.828) and a considerable increase in CAI. A 1 mm increase in bilateral arch height difference corresponded to a 10.7 mm shift in the center of gravity and a 1.58 mm mediolateral displacement in the pressure center ( P < 0.001). Reduced arch height was associated with a marked decline in foot elastic function; specifically, AEI decreased by 62.4 points in the flatfoot++ group (95% confidence interval: –63.379, –61.363), accompanied by a corresponding reduction in PRR. The Hurst exponent deviated significantly from 0.5 in individuals with abnormal foot structures, indicating decreased dynamic postural stability. Conclusion: Abnormal foot arch morphology is closely associated with the impaired biomechanical function of the foot, including reduced postural stability, diminished energy storage and return capacity, and angular deformities. These findings provide a quantitative foundation for injury risk identification and functional foot assessment, and support the integration of arch structure screening into student health management programs. Health sciences/Anatomy Health sciences/Diseases Health sciences/Health care Health sciences/Medical research Health sciences/Risk factors Foot arch morphology Sports injury Biomechanics Hallux valgus Calcaneal Angle Index Postural stability Plantar pressure Hurst index Figures Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 INTRODUCTION The morphology of the foot arch (hereafter referred to as “arch,” specifically indicating the medial longitudinal arch) is a key biomechanical feature of the foot and has profound implications for lower limb function and the risk of sports injuries¹⁻³. Arch types are typically classified into three categories: flatfoot, normal arch, and high arch. Flatfoot—characterized by a collapsed medial longitudinal arch—has been identified as a potential risk factor for lower limb injuries⁴. Individuals with flatfoot exhibit marked hindfoot eversion during the stance phase of gait (flatfoot: − 1.6° ± 5.1°, normal arch: 6.7° ± 3.5°, high arch: 13.6° ± 4.6°), and that peak eversion occurs earlier in the gait cycle². These changes may be attributed to the reduced efficacy of the plantar fascia mechanism, thereby compromising dynamic foot stability. Additionally, increased navicular drop (mean difference, 1.9 mm; 95% confidence interval [CI], 0.54–1.84 mm) has been significantly associated with a heightened risk of medial tibial stress syndrome (MTSS; P < 0.001), suggesting that abnormal pressure distribution in flatfoot contributes to sports-related injuries⁴. Dysfunction of the posterior tibial tendon may further exacerbate this risk, as its loss of function leads to posterior displacement of the center of pressure and increased medial forefoot loading, which promote the progression of flatfoot deformity⁵. The biomechanical implications of arch abnormalities extend beyond the foot, influencing skeletal alignment and force transmission throughout the kinetic chain. Excessive foot pronation has been shown to significantly increase tibial internal rotation, hip internal rotation, and anterior pelvic tilt ( P < 0.001), thereby elevating the risk of lower back pain and lower limb injuries⁶. This association is particularly pronounced in females, among whom foot pronation has been linked to a elevated risk of lower back pain (odds ratio, 1.48; 95% CI, 1.07–2.05, P = 0.018)³. These findings suggest that abnormalities in arch structure amplifies the risk of sports injuries by altering force transmission patterns in the lower extremities and trunk. Moreover, individuals with obesity have been found to exhibit significantly greater arch height and plantar fascia thickness than those with normal body weight ( P < 0.01). These morphological differences are accompanied by reduced ankle evertor strength and impaired balance, which contribute to abnormal foot loading and heightened susceptibility to injuries⁷. University students represent a population frequently experience high physical demands because of their regular participation in sports and physical activities, which impose substantial biomechanical stress on the feet. Considerably, arch morphology may exert a considerable influence on athletic performance and injury risk in this group⁸⁻¹⁰. Although previous studies have explored the biomechanical characteristics of arch morphology and their relationships with specific injuries, comprehensive analyses that address arch morphology distribution, biomechanical traits, and multiple injury risk factors in university students remain limited. Current studies often focus on a single foot type or isolated injury, lacking in-depth investigation of multifactorial interactions³ , ⁴ , ¹¹ , ¹². To address this gap, the present study analyzed arch screening data from 1078 university students using a multifactorial statistical approach. The objective was to systematically investigate the biomechanical characteristics of different arch types and their associations with sports injury risks. The findings are intended to contribute to the scientific foundation for injury prevention and management strategies in student populations. METHODS Study Design​ ​ This cross-sectional study aimed to investigate the biomechanical characteristics of arch morphology and its association with the risk of sports injuries. A total of 1078 university students underwent arch screening, which included the assessment of static biomechanical parameters, such as arch height, hallux valgus angle, and heel tilt angle. In addition, plantar pressure distribution was analyzed using a multifactorial statistical approach. The study was conducted at the Sports Biomechanics Laboratory of Jimei University from October to December 2024. Ethical approval was obtained from the Institutional Review Board of Jimei University, and all participants provided written informed consent. Participants​​ A total of 1078 university students were enrolled in the study. Demographic characteristics are shown in Fig. 1 . The inclusion criteria for participant enrolment were as follows: (1) absence of any history of lower limb fracture or surgery; (2) absence of serious foot or lower limb injuries in the past six months; and (3) ability to complete static foot assessments. Exclusion criteria included: (1) presence of neurological conditions affecting foot measurements and (2) inability to complete testing procedures required for the study. Data Collection and Measurements​ Arch Morphological Features​ ​ Arch morphology, hallux valgus angle, and calcaneal inclination angle were measured using the iFEET Neo 3D foot scanner (iSUN3D, China). This device employs high-precision 3D scanning technology (± 5 mm accuracy; point cloud density, 28/cm²) to capture three-dimensional foot data under static weight-bearing conditions. Key parameters included medial arch height (mm), hallux valgus angle (°), and calcaneal inclination angle (°). Arch types were classified based on predefined height thresholds, while hallux valgus and calcaneal angle categories followed manufacturer-defined standards. During scanning, participants stood barefoot on a glass platform in anatomical neutral posture for 10 s, ensuring that both feet were positioned within the measurement zone (400 mm × 400 mm × 150 mm). All measurements were independently performed by two certified podiatrists. The process demonstrated excellent inter-rater reliability (intraclass correlation coefficient > 0.95). Plantar Pressure Analysis​​ Plantar pressure distribution was assessed using the iGAIT MAX 3D pressure platform (iSUN3D, China; 400 Hz sampling frequency). The system integrates piezoresistive sensors (four gold-plated sensors/cm²; 2.5 DPI resolution; maximum pressure of 150 N/cm²) to quantify center of gravity displacement, mediolateral pressure center deviation, arch elasticity index (AEI), and pressure recovery rate (PRR). Participants completed three 10-second static standing trials on the pressure plate while maintaining natural posture. Data from repeated trials were averaged to minimize intra-subject variability. Postural Stability Assessment​ ​ Coordination Asymmetry Index (CAI) and Hurst exponent were derived from force plate data (Kistler 9286B, Switzerland; 100 Hz sampling frequency). Participants stood barefoot at the force plate center for 15 seconds during data acquisition. Biomechanical Parameter Calculations​ CAI. The \(\:\text{C}\text{A}\text{I}\) evaluates bilateral symmetry of the center of pressure (COP) during static standing, calculated as: \(\:\text{C}\text{A}\text{I}=\frac{|{\text{C}\text{O}\text{P}}_{L}－{\text{C}\text{O}\text{P}}_{R}|}{{(\text{C}\text{O}\text{P}}_{L}+{\text{C}\text{O}\text{P}}_{R})/2}\times\:100\%\) (Eq. 1) where \(\:{\text{C}\text{O}\text{P}}_{L}\) and \(\:{\text{C}\text{O}\text{P}}_{R}\) denote left and right foot pressure center coordinates derived from spatial centroids or moment-based calculations. Elevated \(\:\text{C}\text{A}\text{I}\) values indicate elevated weight-bearing asymmetry and compromised postural stability. Hurst Exponent. The Hurst exponent ( \(\:H\) ) characterizes long-range correlations in COP time-series data through Rescaled Range ( \(\:R/S\) ) analysis. \(\:R/S\left(n\right)=\frac{R\left(n\right)}{S\left(n\right)}\propto\:{n}^{H}\) (Eq. 2) where \(\:\text{n}\) represents time-series length, \(\:R\left(n\right)\) the range of cumulative deviations, and \(\:S\left(n\right)\) the standard deviation (SD). The exponent \(\:\text{H}\) is obtained as the slope of the linear regression between \(\:\text{l}\text{o}\text{g}(R/S)\) and \(\:\text{l}\text{o}\text{g}\left(n\right)\) . An \(\:H\) value of 0.5 indicates uncorrelated random walk dynamics, \(\:H\) >0.5 indicates persistent trends, and \(\:H\) < 0.5 reflects anti-persistent behavior. Analysis utilized a stabilized 10-second window from the mid-portion of vertical pressure data to exclude transient postural adjustments. Environmental Controls ​​ All tests were conducted in a climate-controlled laboratory (22–24°C, 40–60% humidity) to standardize environmental influences on biomechanical measurements. Statistical Analysis​ ​ Data analysis was conducted using SPSS 29.0 (IBM Corp., USA). Descriptive statistics were first applied to characterize bilateral arch height, hallux valgus angle, and calcaneal inclination angle, and results were expressed as mean ± SD for continuous variables and frequency distributions for categorical measures. Missing data (< 5%) were addressed through mean imputation to preserve dataset integrity. To systematically examine associations between arch morphology and biomechanical parameters, a series of regression models were constructed. For the analysis of continuous variables, four simple linear regression models were developed, using unilateral arch height (mm) as the independent variable predicting ipsilateral hallux valgus angle (°) or calcaneal inclination angle (°). Two additional models evaluated bilateral arch height differences (mm) as predictors of sagittal plane center-of-gravity displacement and coronal plane mediolateral pressure center deviation. Categorical analyses employed dummy-coded arch types (reference: normal arch = 0; flatfoot = 1; flatfoot + = 2; flatfoot++ = 3; high-arched = 4) across eight multivariate linear regression models. Four models predicted ipsilateral hallux valgus angles and calcaneal inclination angles, while the remaining four assessed AEIs and PRR. For CAI and Hurst exponent analyses, two mixed-effects models incorporated both categorical predictors (arch type concordance: 0 = concordant, 1 = discordant) and continuous variables (bilateral arch height differences). All models utilized the Enter method and included sex as a covariate to conrol for potential confounding effects. Multicollinearity diagnostics confirmed acceptable variance inflation factors ( VIF < 3.128). Model performance was evaluated using multiple metrics, including R ², adjusted R ², standard error, F-statistics, unstandardized coefficients ( B ), standardized coefficients (Beta), 95% CI, and significance levels ( P values). A priori power analysis conducted in G*Power 3.1 determined a minimum sample size of 146 for multivariate linear regression (effect size f² = 0.15, α = 0.05, power = 0.90, 6 predictors). The final cohort ( N = 1078) provided 7.4-fold excess power, ensuring the robust detection of clinically meaningful effects. All hypothesis tests employed two-tailed evaluation with significance threshold set at P value of < 0.05. RESULTS Morphological Characteristics of the Arch Descriptive statistics were used to analyze arch height, hallux valgus angle, and heel valgus angle by laterality and sex (Fig. 2 ). The distribution of left arch types was as follows: high arch 4.2% (male, 4.6%; female: 3.7%), normal arch 31.9% (male, 35.9%; female, 27.5%), flatfoot 21.1% (male, 19.7%; female, 22.6%), flatfoot + 21.2% (male, 17.2%; female, 25.5%), and flatfoot + + 21.7% (male, 22.7%; female, 20.6%). For the right foot, the proportions were as follows: high arch, 4.7%; normal arch, 34.9%; flatfoot, 22.9%; flatfoot+, 17.9%; and flatfoot++, 19.6%. Regarding hallux valgus, 56.2% of left feet and 64.1% of right feet exhibited valgus deformity (15° < X ≤ 30°). A higher prevalence was observed in females for the right foot (66.4% vs. 62.0% in males). For the heel valgus, 34.2% of left feet and 41.6% of right feet were classified as standard, and females showed a higher incidence of left heel valgus (30.3% vs. 23.2% in males). The consistency rate of arch types between left and right feet was 55.9% (male, 57.3%; female, 54.4%), and the average arch height difference was 1.15 ± 1.00 mm (male, 1.18 ± 1.02 mm; female, 1.12 ± 0.98 mm). The consistency rate for hallux valgus was 64.0%, and the average angle difference was 6.38 ± 6.16° (male, 6.56° ± 6.19°; female, 6.17° ± 6.13°). The consistency rate for heel valgus was 54.6%, with an average angle difference of 4.12° ± 3.51° (male, 4.14° ± 3.50°; female, 4.11° ± 3.53°). Hallux Valgus Angle​ ​ Arch morphology showed significant laterality-specific biomechanical regulation of hallux valgus (Supplementary Table 1). In the left foot continuous model, arch height was negatively correlated with hallux valgus angle in a nonlinear fashion ( B = − 1.105, 95% CI [− 1.324, − 0.886], P = 0.001). Each millimeter increase in arch height decreased the valgus angle by 1.1°, although the model’s explanatory power was limited ( R ² = 8.4%). The categorical model revealed effect size exponentially increased with the degree of morphological deformation: the effect sizes for flatfoot ( B = 14.928), flatfoot+ ( B = 15.664), flatfoot++ ( B = 18.080), and high arch ( B = 35.303) showed a 2.36-fold gradient ( P < 0.001), and the model accounted for 76.2% of the variation. A similar trend was observed for the right foot, although the effect size was considerably reduced, and the high arch effect ( B = 11.129) was only 31.5% of the left foot's effect ( P < 0.001). Additionally, the upper limit of the 95% CI for the left high arch (36.875°) exceeded the lower limit for the right foot (8.833°), suggesting that anatomical asymmetry induced unilateral compensatory mechanisms (Fig. 3 ). Heel Valgus Angle Changes in arch structure elicited bidirectional regulation of heel 3D biomechanics (Supplementary Table 1). In the left foot continuous model, arch height showed a strong negative correlation with heel valgus angle ( B = − 2.447, P < 0.001), accounting for 82.8% of the variance, which indicated that a 1 mm decrease in arch height led to a 2.45° increase in heel valgus. The categorical model demonstrated a graded response in biomechanical effects due to morphological deformation: flatfoot ( B = 5.582), flatfoot+ ( B = 8.943), and flatfoot++ ( B = 15.412) exhibited a 2.76-fold difference in effect size ( P < 0.001), whereas high arch showed a correction of 8.66° inversion ( B = − 8.659, P < 0.001). The analysis of the right foot revealed similar trends, but showed a 12.3% reduction in effect size. The effect for flatfoot++ ( B = 13.272) surpassed the left foot’s normal arch baseline. Additionally, the SD value of the change in heel valgus angle for the left foot (3.01°) was significantly higher than that for the right foot (2.76°), and the largest laterality difference was observed in flatfoot++ (Δ B = 2.14°, 95% CI [1.89, 2.39]; Fig. 3 ). Arch Height Difference and Stability Asymmetry in bilateral arches considerably affected postural stability, exhibiting a dose-response relationship (Supplementary Table 2). Regression analysis showed that for every 1 mm increase in arch height difference, center of mass displacement increased by 10.725 mm (95% CI [10.067, 11.383]) and the left–right pressure center misalignment increased by 1.58 mm (95% CI [1.476, 1.684]), with a strength ratio of 6.8:1 ( β = 0.698 vs. 0.672). These finding suggests that sagittal plane stability is easily influenced by arch asymmetry. Bivariate visualization further revealed that when arch height difference exceeded 3.2 mm, 95% of individuals experienced pressure misalignment exceeding the 5 mm clinical risk threshold. Arch height differences of ≥ 5 mm elicited a 18.6% nonlinear increase in center of mass displacement. The difference in the width of the CI between the two models (1.32 mm vs. 0.21 mm) reflected strong compensatory interference in the sagittal plane, providing dual criteria for personalized orthotics based on spatial sensitivity and mechanical determinism (Fig. 4 ). Arch Elasticity Index (AEI) Arch morphological deformities led to a systematic reduction in energy storage function (Supplementary Table 3). In the left foot categorical model, flatfoot + + reduced AEI by 62.371 (95% CI [− 63.379, − 61.363]), which corresponded to 38.7% of the energy storage function of a normal arch ( P < 0.001). Right foot analysis showed a similar trend, but the high arch effect was diminished by 9.8% ( B = − 37.356 vs. −41.859). The pyramid chart revealed that left foot deformation caused considerable elastic damage. The laterality difference for flatfoot + + reached 0.48 SD values (Cohen's d = 0.48), and 95% CI (− 0.52, − 0.44) entirely deviated from zero (Fig. 5 ). The effect size gradient across all deformity types followed a distinct pattern. Flatfoot++ ( d = 2.01) demonstrated the greatest biomechanical impact, followed by flatfoot+ ( d = 1.35), high arch (d = 0.98), and flatfoot (d = 0.62). Pressure Recovery Rate (PRR)​​ Arch structural integrity is crucial for shock absorption (Supplementary Table 3). In the left foot, flatfoot + + reduced PRR by 0.513 (95% CI [− 0.518, − 0.507]), indicating that only 51.3% of the normal arch function remained ( P < 0.001). Right foot analysis showed that flatfoot+ ( B = − 0.308) and high arch ( B = − 0.312) had comparable effect sizes, suggesting that lateral arch damage led to equivalent functional loss. The absolute effect size for left foot PRR damage (mean Δ = 0.307) was considerably higher than that for the right foot (Δ = 0.291; Fig. 5 ). Temporal analysis revealed that the half-life of the left foot pressure recovery curve increased by 23.6% ( P < 0.001). Coordination Asymmetry Index (CAI)​​ Arch abnormalities induced compensatory imbalance in bilateral pressure distribution (Supplementary Table 4). Left foot flatfoot + + increased CAI by 0.302 ( P < 0.001), equivalent to 3.2 SD of normal arch pressure asymmetry. Right foot high arch had the strongest effect ( B = 0.341, P < 0.001), with its 95% CI (0.277, 0.406) fully covering the left foot flatfoot + + range [0.251, 0.353]. The effect size of bilateral arch type differences ( B = 0.41, P < 0.001) was 15.8 times that of the height difference ( B = 0.026), accounting for 59.6% of the model’s explanatory power. Additionally, the asymmetry effect for left foot deformities (mean B = 0.212) was significantly higher than for the right foot ( B = 0.170), and the effect strength of type differences increased logarithmically with the degree of deformity ( R ² = 0.872; Fig. 6 ). Hurst Exponent​​ Changes in arch structure remodeled the long-term stability of pressure distribution (Supplementary Table 4). Left foot flatfoot + + decreased the Hurst index by 0.21 (95% CI [− 0.233, − 0.188]), indicating a 37.2% reduction in long-term correlation of pressure time series ( P < 0.001). In contrast, right foot high arch produced a positive modulation of 0.133 ( P < 0.001), with the effect direction being mirror-symmetric to that of the left foot ( r = − 0.786, P = 0.002). The bilateral arch height difference was negatively correlated with the Hurst index ( B = − 0.023, P < 0.001), attenuating 38.7% of the positive effects of type differences. Furthermore, the stability damage for left foot deformities was pronounced. The laterality difference (ΔB) for flatfoot + + was 0.09 (95% CI [0.07, 0.11]), and the effect size gradient following a power law distribution ( R ² = 0.943; Fig. 6 ). DISCUSSION​ Mechanisms of Arch Variations in Forefoot Bony Deformities This study identified a considerably modulatory effect of that arch structure on hallux valgus angle, especially in the left foot. Regression analysis revealed that for each 1 mm decrease in left arch height was associated with a 1.105° increase in hallux valgus angle ( B = − 1.105, P = 0.001). This finding is highly consistent with the strong correlation proposed by Eustace et al. 13 between medial longitudinal arch angle and the first metatarsal rotation ( r = 0.93). The classification models showed that the hallux valgus angle in the left foot flatfoot + + group reached 18.08°, which significantly higher than that observed in the normal arch group ( P < 0.001). This result corroborates the pathological mechanism through which arch collapse leads to first metatarsal internal rotation (pronation) and subsequent axis deviation of the first metatarsal 13,14 . Notably, the high-arch group exhibited an abnormal increase in the left foot hallux valgus angle to 35.303°, which markedly exceeded that of the flatfoot + + group. This finding aligns with that of Steadman et al. 14 , where high-arched feet adopt a compensatory pronation mechanism. In such cases, forefoot load is concentrated on the first and second metatarsal heads. Pressure concentration is exacerbated in females because of their smaller shoe sizes, leading to increased medial pressure peaks and structural deformities 4 . The “U-shaped curve” observed in this study (flatfoot and high arch worsen hallux valgus) underscores the need to reframe clinical management strategies. Rather than adopting a “flatfoot-centric” approach, clinical assessment ann intervention should incorporate the biomechanical evaluation of high-arched feet. The relationship in the right foot was weak (continuous model B = − 0.483, P = 0.001) possibly because of the enhanced muscular compensation ability of the dominant foot. Data showed that the hallux valgus angle in the right foot high-arch group (11.129°) was significantly lower than that in the left foot (35.303°), and gender differences were small (male 7.9% vs. female 6.5%). These results corroborates the hypothesis of Yang et al. 15 , which suggests that muscle control on the dominant side serves as a buffering mechanism against deformation. Mechanisms of Arch Variations on Rearfoot Tilt The strong correlation between arch collapse and rearfoot eversion was especially prominent in the left foot. The continuous model showed that a 1 mm decrease in arch height resulted in 2.45° increase in rearfoot eversion ( B = − 2.447, P < 0.001). This result aligns with Eustace’s model 13 on the synergistic motion theory of calcaneal eversion, where the collapse of the medial longitudinal arch causes internal rotation at the subtalar joint and ultimately leads to an exponential increase in calcaneal eversion angle (with flatfoot + + group rearfoot eversion reaching 15.412°). The anatomical mechanism can be explained as follows: Arch collapse results in loss of tension in the posterior tibial and spring ligament complex, causing the calcaneus to evert because of the loss of medial support 16 . Meanwhile, a change in the plantar fascia pull direction further exacerbates rearfoot line deviation 17 . By contrast, the high arch group exhibited an inverse mechanism, and the left foot calcaneal inversion angle reached − 8.659° ( P < 0.001). This change may be to an increase in plantar fascia angle (PFA). Jiang et al. 17 suggests that an increase in PFA in high-arched feet leads to a lateral shift in the calcaneal load-bearing zone (particularly at the base of the fifth metatarsal), causing stress concentration on the lateral column and forcing the calcaneus to invert to maintain balance. Changes in the right foot were small (continuous model B = − 2.252 vs. left foot − 2.447). In the classification model, the rearfoot eversion in the flatfoot + + group still reached 13.272°, suggesting differences in bilateral compensation mechanisms. Impact of Arch Asymmetry on Postural Control and Neurological Regulation This study found a considerable relationship between arch asymmetry and postural stability. Regression analysis showed a 1 mm increase in the difference in arch height between the left and right feet elicits a 10.725 mm shift in the center of gravity ( B = 10.725, P < 0.001), and the mediolateral center of pressure deviation increased by 1.58 mm ( B = 1.58, P < 0.001). These findings are consistent with those of Mandal et al. 18 , who concluded that arch differences disrupt proprioceptive input by causing asymmetric pressure distribution and amplify errors in spinal cord and cerebellar postural regulation. The finite element model of Peng 19 further confirms this mechanism. Arch differences alter the synergistic activation pattern of the posterior tibial and fibular longus muscles, thus reducing the efficiency of the lower limb kinetic chain and increasing the central nervous system’s burden for postural control. Gu et al. 20 clinically validated this mechanism. After correcting arch differences with Scarf osteotomy combined with subtalar joint stabilization, follow-up after one year showed considerable improvements in HVA, IMA, Meary’s angle, calcaneal tilt angle, and talocalcaneal angle ( P < 0.001). This finding suggests that restoring bilateral mechanical balance through arch reconstruction can enhance neuromuscular regulation efficiency. Regulation of Elastic Energy Storage Systems by Arch Variations This study found a considerable effect of abnormal arch morphology on the foot’s elastic energy storage function. In the left foot flatfoot + + group, the AEI decreased by 62.371 units ( B = − 62.371, P < 0.001), and the PRR decreased by 0.513 units ( B = − 0.513, P < 0.001), indicating that arch collapse disrupts energy metabolism through dual mechanisms: (1) Plantar Fascia Dysfunction: The overstretched plantar fascia loses pre-tension capacity because of excessive elongation 21 , leading to a considerable decline in elastic potential energy storage. This mechanism aligns with that described by Cifuentes-De la Portilla et al. 22 , who demonstrated that arch collapse reduces proximal plantar fascial stress while amplifying distal strain. (2) Compensatory Tendon Overload: Posterior tibial tendon hyperactivation concentrates pressure on the medial forefoot, further impairing energy return efficiency during push-off 5 . High-arched individuals exhibited a significant decrease in AEI (left foot B = − 41.859, P < 0.001), which is related to the lack of shock absorption in rigid arches. The kinematic data of Kruger et al. 2 showed that high-arched individuals have peak rearfoot inversion angles of 13.6° ± 4.6°, which limits the deformability of the arch, and shock forces are directly transmitted through the calcaneus to the knee joint. These data aligns with the findings of Ledoux et al. 1 , who demonstrated increased pressure peaks at the metatarsal heads in high-arched individuals with diabetic foot. Impact of Arch Asymmetry on Gait Coordination and Dynamic Stability Arch asymmetry considerably influences gait coordination and dynamic stability. A one-level increase in the difference in arch type between the left and right feet led to 0.41 increase in CAI ( B = 0.41, P < 0.001). In addition, the Hurst exponent decreased by 0.019 units ( B = − 0.019, P = 0.007), indicating that arch differences lead to disordered gait pressure distribution and increased randomness. In the left foot flatfoot + + group, CAI reached 0.302 ( P < 0.001), suggesting an imbalance in pressure distribution between the medial forefoot and lateral rearfoot. This finding corresponds to the conclusions of Imhauser et al. 5 , whose in vitro model demonstrated that posterior tibial tendon dysfunction leads to a posterior shift in the pressure center, forcing abnormal loading on the medial forefoot and disrupting the sequential transmission of gait forces. The decrease in the Hurst exponent (left foot flatfoot + + group B = − 0.21, P < 0.001) reflects the increased compensatory burden on the central nervous system, which must adjust through high-frequency muscle activation to maintain balance. This finding aligns with that of Menz et al. 3 , who proposed the “foot dysfunction–spinal compensation” hypothesis stating that foot dysfunction potentially leads to an increased risk of knee valgus and low back pain in the long term 4 . By contrast, the high-arched group exhibited an abnormal increase in the Hurst exponent (right foot B = 0.133, P < 0.001), indicating gait rhythm stiffening and reduced dynamic adaptability, further supporting the conclusion of Kruger et al. 2 regarding the deterioration of kinematic stability in high-arched individuals. Sports Practice and Clinical Rehabilitation Implications​ ​ The identified associations between arch abnormalities and multifactorial biomechanical dysfunction underscore critical applications in sports training and clinical rehabilitation. Athletic Training Considerations ​​ Incorporating arch morphology screening (height, symmetry, and elasticity index) into pre-participation assessments facilitates targeted injury prevention. For flatfoot individuals, evidence-based interventions should emphasize intrinsic foot muscle strengthening through short-foot exercises. Cheng et al. 23 reported considerably improvement navicular drop test outcomes after six-week regimens. High-arched individuals require prioritized ankle mobility training and footwear with enhanced midfoot cushioning to alleviate lateral column stress concentrations. This recommendation is consistent with the observations of Kruger et al. 2 regarding compensatory hindfoot inversion mechanics. Clinical Rehabilitation Strategies ​​ Personalized orthotic prescriptions must integrate dynamic pressure mapping, particularly for cases with bilateral height disparities of > 3.2 mm and CAI of > 0.3. Gu et al. 20 combined Scarf osteotomy and subtalar arthroereisis protocol to achieve significant mechanical normalization ( P < 0.001). Although artificial intelligence–driven orthosis design shows promise, overreliance on static parameters risks suboptimal load redistribution 24 . Hence, clinicians should monitor neuromechanical sequelae: Menz et al. 3 linked foot dysfunction to 48% increase in low-back pain risk in females (OR = 1.48). Winkelmann et al. 4 associated 1.9 mm navicular drop increases with 23% increase in MTSS incidence. Integrating plantar sensory augmentation and cortical feedback mechanisms may counteract arch-mediated postural degradation, especially in older cohorts and those with neurological disorders, who are prone to falls. Limitations and Future Directions​ ​ This study advances understanding of arch biomechanics, but several limitations warrant consideration. The exclusive focus on 18–25-year-old university students restricts generalizability across developmental stages and aging populations, underscoring the need for the recruitment adolescents and older adults to capture lifespan-related arch adaptations. Methodologically, reliance on static parameters overlooks dynamic functional responses. This gap should be addressed through the multimodal integration of 3D gait analysis, force plate kinetics, and surface electromyography into the formulation of map load redistribution patterns during locomotion 25,26 . Although cross-sectional associations are robust, causation remains inferential. The longitudinal tracking of arch deterioration trajectories and randomized controlled trials assessing orthotic or surgical interventions would strengthen mechanistic claims. The observed left-foot predominance in structural alterations highlights the need for neurophysiological exploration through functional MRI and transcranial magnetic stimulation to unravel central sensorimotor compensation mechanisms in dominant limbs. Collectively, these directions may transform static morphological descriptions into dynamic and clinically actionable models of foot function. CONCLUSION This study, grounded in a large sample size, comprehensive biomechanical metrics, and robust statistical modeling, systematically elucidates the complex relationships between foot arch morphology and key functional parameters of the foot and lower limb. Our findings reveal that reduced and elevated arch heights can cause structural deformities, such as forefoot malalignment and calcaneal eversion, through distinct mechanisms. Additionally, bilateral arch asymmetry considerably impairs postural control and proprioceptive feedback, elevating the risk of postural instability. Abnormal arch morphology markedly diminishes the foot’s elastic energy storage capacity, compromising gait efficiency and altering plantar responses to ground reaction forces. These insights not only advance the theoretical understanding of the biomechanical coupling between arch structure and foot function but also provide critical parameters for injury prevention, sports screening, rehabilitation design, and the development of intelligent intervention systems. We advocate for the broader adoption of foot arch assessments across diverse age groups and pathological populations and their integration into dynamic monitoring and longitudinal follow-up strategies. Such efforts will facilitate a shift from static structural analyses to dynamic functional optimization, offering data-driven support and technological foundations for precision sports medicine and smart rehabilitation. Declarations Ethics Approval and Consent to Participate This study was approved by the Ethics Committee of the School of Physical Education, Jimei University, and conducted in accordance with the principles of the Declaration of Helsinki. Written informed consent was obtained from all 1078 university student participants from Jimei University prior to enrollment. Consent for Publication Not applicable. This manuscript does not contain personally identifiable data, images, or videos from any individual. Availability of Data and Materials Data is provided within the manuscript or supplementary information files. Competing Interests The authors declare no competing financial or non-financial interests. The funders had no role in study design, implementation, or manuscript preparation. Funding This work was supported by the National Social Science Fund of China [Grant Number 23TYB00862]. Author Contributions Conceptualization: X.W., J.Y.; Methodology: Z.X., Y.L., Y.C.; Investigation: Z.X., Y.L., L.Y.; Data Curation: Y.C., L.Y.; Writing—Original Draft: Z.X., Y.L.; Writing—Review & Editing: Z.X., Y.L., X.W., J.Y.; Resources: X.W., J.Y.; Supervision: X.W., J.Y. Acknowledgements We sincerely thank the 1078 university students from Jimei University for their participation and all research collaborators for their invaluable contributions. Special recognition is given to the students whose dedication was fundamental to this study's success. Clinical Trial Number Clinical trial number: not applicable. References Ledoux WR, Shofer JB, Ahroni JH, Smith DG, Sangeorzan BJ, Boyko EJ. Biomechanical differences among pes cavus, neutrally aligned, and pes planus feet in subjects with diabetes. Foot Ankle Int . 2003;24(11):845-850. doi:10.1177/107110070302401107 Kruger KM, Graf A, Flanagan A, et al. Segmental foot and ankle kinematic differences between rectus, planus, and cavus foot types. J Biomech . 2019;94:180-186. doi:10.1016/j.jbiomech.2019.07.032 Menz HB, Dufour AB, Riskowski JL, et al. Foot posture, foot function and low back pain: the Framingham Foot Study. Rheumatology (Oxford) . 2013;52(12):2275-2282. doi:10.1093/rheumatology/ket298 Winkelmann ZK, Anderson D, Games KE, et al. Risk factors for medial tibial stress syndrome in active individuals: an evidence-based review. J Athl Train . 2016;51(12):1049-1052. doi:10.4085/1062-6050-51.12.13 Imhauser CW, Siegler S, Abidi NA, et al. The effect of posterior tibialis tendon dysfunction on the plantar pressure characteristics and the kinematics of the arch and the hindfoot. Clin Biomech (Bristol) . 2004;19(2):161-169. doi:10.1016/j.clinbiomech.2003.10.007 Khamis S, Yizhar Z. Effect of feet hyperpronation on pelvic alignment in a standing position. Gait Posture . 2007;25(1):127-134. doi:10.1016/j.gaitpost.2006.02.005 Park SY, Park DJ. Comparison of foot structure, function, plantar pressure and balance ability according to the body mass index of young adults. Osong Public Health Res Perspect . 2019;10(2):102-107. doi:10.24171/j.phrp.2019.10.2.09 Zhang QL, Song SX, Dong J. Characteristics of plantar pressure distribution parameters in healthy college students. Chin J Sch Health . 2007;(9):814-816. Kong DG, Gao H, Wang L. Comparison of plantar pressure and gait characteristics between male college students with flatfoot and normal arches. Chin J Sch Health . 2013;34(6):680-685. doi:10.16835/j.cnki.1000-9817.2013.06.015 Kim EK, Kim JS. The effects of short foot exercises and arch support insoles on improvement in the medial longitudinal arch and dynamic balance of flexible flatfoot patients. J Phys Ther Sci . 2016;28(12):3136-3139. doi:10.1589/jpts.28.3136 Mei QC, Xiang LL, Sun D, et al. Increased knee medial contact force after long-distance running due to "foot valgus": a musculoskeletal modeling and machine learning prediction study. J Sports Sci . 2019;39(9):51-59. doi:10.16469/j.css.201909006 Mao XK, Zhang QX, Lu AM, et al. Kinetic characteristics of high-arched feet during running stance phase. J Phys Educ . 2017;24(2):122-127. doi:10.16237/j.cnki.cn44-1404/g8.20170121.002 Eustace S, Byrne JO, Beausang O, et al. Hallux valgus, first metatarsal pronation and collapse of the medial longitudinal arch—a radiological correlation. Skeletal Radiol . 1994;23(3):191-194. doi:10.1007/BF00197458 Steadman J, Barg A, Saltzman CL. First metatarsal rotation in hallux valgus deformity. Foot Ankle Int . 2021;42(4):510-522. doi:10.1177/1071100721997149 Yang F, Wu C, Wang J, et al. Subtalar arthroereisis for simultaneous treatment of flexible pes planus during surgical correction of hallux valgus. Eur J Med Res . 2025;30(1):44. doi:10.1186/s40001-025-02299-8 Wong YS. Influence of the abductor hallucis muscle on the medial arch of the foot: a kinematic and anatomical cadaver study. Foot Ankle Int . 2007;28(5):617-620. doi:10.3113/FAI.2007.0617 Jiang Z, Zhang Q, Ren L, et al. Non-invasive and quantitive analysis of flatfoot based on ultrasound. Front Bioeng Biotechnol . 2022;10:961462. doi:10.3389/fbioe.2022.961462 Mandal S, Mandal P, Basu R. Study of variations in the medial longitudinal arch leading to development of adult acquired flat foot. Int J Med Pharm Sci . 2013;5(3):12-18. Peng Y. Biomechanical study of adult acquired flatfoot for intervention. J Biomech Eng . 2022;144(7):071006. doi:10.1115/1.4054156 Gu W, Fu S, Wang C, et al. Outcomes of simultaneous correction of adult hallux valgus and flexible pes planus deformities. Orthopedics . 2025;48(1):37-43. doi:10.3928/01477447-20241213-03 Yamamoto H, Muneta T, Asahina S, et al. Forefoot pressures during walking in feet afflicted with hallux valgus. Clin Orthop Relat Res . 1996;(323):247-253. Cifuentes-De la Portilla C, Larrainzar-Garijo R, Bayod J. Biomechanical stress analysis of the main soft tissues associated with the development of adult acquired flatfoot deformity. Clin Biomech (Bristol) . 2019;61:163-171. doi:10.1016/j.clinbiomech.2018.12.009 Cheng J, Han D, Qu J, et al. Effects of short foot training on foot posture in patients with flatfeet: a systematic review and meta-analysis. J Back Musculoskelet Rehabil . 2024;37(3):839-851. doi:10.3233/BMR-230226 Hoang NTT, Chen S, Chou LW. The impact of foot orthoses and exercises on pain and navicular drop for adult flatfoot: a network meta-analysis. Int J Environ Res Public Health . 2021;18(15):8063. doi:10.3390/ijerph18158063 Bai XT, Huo HF. Biomechanical evaluation of foot and ankle function: constructing static and dynamic assessment indicators. Chin J Tissue Eng Res . 2021;25(17):2747-2754. Liu J, Deng M, Wang W, et al. A foot structure study of new arch flexibility grading system based on three-dimensional arch volume. Chin J Traumatol . 2023;26(5):329-333. doi:10.1016/j.cjtee.2023.09.002 Additional Declarations No competing interests reported. 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2","display":"","copyAsset":false,"role":"figure","size":853787,"visible":true,"origin":"","legend":"\u003cp\u003eArch Morphological Characteristics of Participants\u003c/p\u003e","description":"","filename":"2.png","url":"https://assets-eu.researchsquare.com/files/rs-7090359/v1/e353a33102754081d719295b.png"},{"id":86847237,"identity":"185c25db-413e-4b85-8e29-a09ea4535ea5","added_by":"auto","created_at":"2025-07-16 09:05:45","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":209039,"visible":true,"origin":"","legend":"\u003cp\u003eMultivariate Regression Analysis of Arch Morphology Effects on Bilateral Hallux Valgus and Calcaneal Inclination Angles​\u003c/p\u003e","description":"","filename":"3.png","url":"https://assets-eu.researchsquare.com/files/rs-7090359/v1/6fba30aaec393952de35d54b.png"},{"id":86845921,"identity":"c7983157-35f8-4c03-bafa-93d72da29a48","added_by":"auto","created_at":"2025-07-16 08:49:45","extension":"png","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":25494,"visible":true,"origin":"","legend":"\u003cp\u003eBilateral Arch Asymmetry Effects on Postural Stability: Multivariate Regression Analysis​​\u003c/p\u003e","description":"","filename":"4.png","url":"https://assets-eu.researchsquare.com/files/rs-7090359/v1/945aff81f37cb99f431bb98f.png"},{"id":86845925,"identity":"c642bc10-410f-48ff-b05b-9e3dc55d5abf","added_by":"auto","created_at":"2025-07-16 08:49:45","extension":"png","order_by":5,"title":"Figure 5","display":"","copyAsset":false,"role":"figure","size":140713,"visible":true,"origin":"","legend":"\u003cp\u003eArch Morphology Effects on AEI and PRR: Multivariate Regression Analysis (Bilateral)​​\u003c/p\u003e","description":"","filename":"5.png","url":"https://assets-eu.researchsquare.com/files/rs-7090359/v1/35868ce0ccc2aa4564df9682.png"},{"id":86845928,"identity":"5f745b95-6b6b-4fe4-9f0b-11fe8c635696","added_by":"auto","created_at":"2025-07-16 08:49:45","extension":"png","order_by":6,"title":"Figure 6","display":"","copyAsset":false,"role":"figure","size":132864,"visible":true,"origin":"","legend":"\u003cp\u003eArch Morphology Effects on CAI and Hurst Index: Multivariate Regression Analysis​​\u003c/p\u003e","description":"","filename":"6.png","url":"https://assets-eu.researchsquare.com/files/rs-7090359/v1/2085b96d2719888d1d93d7fc.png"},{"id":102234019,"identity":"d3b567eb-c49e-4627-8326-1d7a6a904bb0","added_by":"auto","created_at":"2026-02-09 16:04:02","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":2255084,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-7090359/v1/34c6b76f-53fd-4e43-9833-755fb6aea7a0.pdf"},{"id":86846896,"identity":"e1bf29da-e9ae-464e-b532-116fcf5994a7","added_by":"auto","created_at":"2025-07-16 08:57:45","extension":"docx","order_by":1,"title":"","display":"","copyAsset":false,"role":"supplement","size":39028,"visible":true,"origin":"","legend":"","description":"","filename":"SUPPLEMENT.docx","url":"https://assets-eu.researchsquare.com/files/rs-7090359/v1/5bce765cc8bff17b12729738.docx"}],"financialInterests":"No competing interests reported.","formattedTitle":"Biomechanical Correlates between Foot Arch Morphology and Sports Injury Risks: a Multifactorial Analysis of 1078 University Students","fulltext":[{"header":"INTRODUCTION","content":"\u003cp\u003eThe morphology of the foot arch (hereafter referred to as “arch,” specifically indicating the medial longitudinal arch) is a key biomechanical feature of the foot and has profound implications for lower limb function and the risk of sports injuries¹⁻³. Arch types are typically classified into three categories: flatfoot, normal arch, and high arch. Flatfoot—characterized by a collapsed medial longitudinal arch—has been identified as a potential risk factor for lower limb injuries⁴. Individuals with flatfoot exhibit marked hindfoot eversion during the stance phase of gait (flatfoot: − 1.6° ± 5.1°, normal arch: 6.7° ± 3.5°, high arch: 13.6° ± 4.6°), and that peak eversion occurs earlier in the gait cycle². These changes may be attributed to the reduced efficacy of the plantar fascia mechanism, thereby compromising dynamic foot stability. Additionally, increased navicular drop (mean difference, 1.9 mm; 95% confidence interval [CI], 0.54–1.84 mm) has been significantly associated with a heightened risk of medial tibial stress syndrome (MTSS; \u003cem\u003eP\u003c/em\u003e \u0026lt; 0.001), suggesting that abnormal pressure distribution in flatfoot contributes to sports-related injuries⁴. Dysfunction of the posterior tibial tendon may further exacerbate this risk, as its loss of function leads to posterior displacement of the center of pressure and increased medial forefoot loading, which promote the progression of flatfoot deformity⁵.\u003c/p\u003e\u003cp\u003eThe biomechanical implications of arch abnormalities extend beyond the foot, influencing skeletal alignment and force transmission throughout the kinetic chain. Excessive foot pronation has been shown to significantly increase tibial internal rotation, hip internal rotation, and anterior pelvic tilt (\u003cem\u003eP\u003c/em\u003e \u0026lt; 0.001), thereby elevating the risk of lower back pain and lower limb injuries⁶. This association is particularly pronounced in females, among whom foot pronation has been linked to a elevated risk of lower back pain (odds ratio, 1.48; 95% CI, 1.07–2.05, \u003cem\u003eP\u003c/em\u003e = 0.018)³. These findings suggest that abnormalities in arch structure amplifies the risk of sports injuries by altering force transmission patterns in the lower extremities and trunk. Moreover, individuals with obesity have been found to exhibit significantly greater arch height and plantar fascia thickness than those with normal body weight (\u003cem\u003eP\u003c/em\u003e \u0026lt; 0.01). These morphological differences are accompanied by reduced ankle evertor strength and impaired balance, which contribute to abnormal foot loading and heightened susceptibility to injuries⁷.\u003c/p\u003e\u003cp\u003eUniversity students represent a population frequently experience high physical demands because of their regular participation in sports and physical activities, which impose substantial biomechanical stress on the feet. Considerably, arch morphology may exert a considerable influence on athletic performance and injury risk in this group⁸⁻¹⁰. Although previous studies have explored the biomechanical characteristics of arch morphology and their relationships with specific injuries, comprehensive analyses that address arch morphology distribution, biomechanical traits, and multiple injury risk factors in university students remain limited. Current studies often focus on a single foot type or isolated injury, lacking in-depth investigation of multifactorial interactions³\u003csup\u003e,\u003c/sup\u003e⁴\u003csup\u003e,\u003c/sup\u003e¹¹\u003csup\u003e,\u003c/sup\u003e¹².\u003c/p\u003e\u003cp\u003eTo address this gap, the present study analyzed arch screening data from 1078 university students using a multifactorial statistical approach. The objective was to systematically investigate the biomechanical characteristics of different arch types and their associations with sports injury risks. The findings are intended to contribute to the scientific foundation for injury prevention and management strategies in student populations.\u003c/p\u003e"},{"header":"METHODS","content":"\u003cp\u003e\u003cb\u003eStudy Design​\u003c/b\u003e​\u003c/p\u003e\u003cp\u003eThis cross-sectional study aimed to investigate the biomechanical characteristics of arch morphology and its association with the risk of sports injuries. A total of 1078 university students underwent arch screening, which included the assessment of static biomechanical parameters, such as arch height, hallux valgus angle, and heel tilt angle. In addition, plantar pressure distribution was analyzed using a multifactorial statistical approach. The study was conducted at the Sports Biomechanics Laboratory of Jimei University from October to December 2024. Ethical approval was obtained from the Institutional Review Board of Jimei University, and all participants provided written informed consent.\u003c/p\u003e\u003cp\u003e\u003cb\u003eParticipants​​\u003c/b\u003e\u003c/p\u003e\u003cp\u003eA total of 1078 university students were enrolled in the study. Demographic characteristics are shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e. The inclusion criteria for participant enrolment were as follows: (1) absence of any history of lower limb fracture or surgery; (2) absence of serious foot or lower limb injuries in the past six months; and (3) ability to complete static foot assessments. Exclusion criteria included: (1) presence of neurological conditions affecting foot measurements and (2) inability to complete testing procedures required for the study.\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003e\u003cb\u003eData Collection and Measurements​\u003c/b\u003e\u003c/p\u003e\u003cp\u003e\u003cem\u003eArch Morphological Features​\u003c/em\u003e\u003cb\u003e​\u003c/b\u003e\u003c/p\u003e\u003cp\u003eArch morphology, hallux valgus angle, and calcaneal inclination angle were measured using the iFEET Neo 3D foot scanner (iSUN3D, China). This device employs high-precision 3D scanning technology (± 5 mm accuracy; point cloud density, 28/cm²) to capture three-dimensional foot data under static weight-bearing conditions. Key parameters included medial arch height (mm), hallux valgus angle (°), and calcaneal inclination angle (°). Arch types were classified based on predefined height thresholds, while hallux valgus and calcaneal angle categories followed manufacturer-defined standards. During scanning, participants stood barefoot on a glass platform in anatomical neutral posture for 10 s, ensuring that both feet were positioned within the measurement zone (400 mm × 400 mm × 150 mm). All measurements were independently performed by two certified podiatrists. The process demonstrated excellent inter-rater reliability (intraclass correlation coefficient \u0026gt; 0.95).\u003c/p\u003e\u003cp\u003e\u003cem\u003ePlantar Pressure Analysis​​\u003c/em\u003e\u003c/p\u003e\u003cp\u003ePlantar pressure distribution was assessed using the iGAIT MAX 3D pressure platform (iSUN3D, China; 400 Hz sampling frequency). The system integrates piezoresistive sensors (four gold-plated sensors/cm²; 2.5 DPI resolution; maximum pressure of 150 N/cm²) to quantify center of gravity displacement, mediolateral pressure center deviation, arch elasticity index (AEI), and pressure recovery rate (PRR). Participants completed three 10-second static standing trials on the pressure plate while maintaining natural posture. Data from repeated trials were averaged to minimize intra-subject variability.\u003c/p\u003e\u003cp\u003e\u003cem\u003ePostural Stability Assessment​\u003c/em\u003e​\u003c/p\u003e\u003cp\u003eCoordination Asymmetry Index (CAI) and Hurst exponent were derived from force plate data (Kistler 9286B, Switzerland; 100 Hz sampling frequency). Participants stood barefoot at the force plate center for 15 seconds during data acquisition.\u003c/p\u003e\u003cp\u003e\u003cem\u003eBiomechanical Parameter Calculations​\u003c/em\u003e\u003c/p\u003e\u003cp\u003e\u003cb\u003eCAI.\u003c/b\u003e The \u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\(\\:\\text{C}\\text{A}\\text{I}\\)\u003c/span\u003e\u003c/span\u003e evaluates bilateral symmetry of the center of pressure (COP) during static standing, calculated as:\u003c/p\u003e\u003cp\u003e\u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\(\\:\\text{C}\\text{A}\\text{I}=\\frac{|{\\text{C}\\text{O}\\text{P}}_{L}－{\\text{C}\\text{O}\\text{P}}_{R}|}{{(\\text{C}\\text{O}\\text{P}}_{L}+{\\text{C}\\text{O}\\text{P}}_{R})/2}\\times\\:100\\%\\)\u003c/span\u003e\u003c/span\u003e (Eq.\u0026nbsp;1)\u003c/p\u003e\u003cp\u003ewhere \u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\(\\:{\\text{C}\\text{O}\\text{P}}_{L}\\)\u003c/span\u003e\u003c/span\u003e and \u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\(\\:{\\text{C}\\text{O}\\text{P}}_{R}\\)\u003c/span\u003e\u003c/span\u003e denote left and right foot pressure center coordinates derived from spatial centroids or moment-based calculations. Elevated \u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\(\\:\\text{C}\\text{A}\\text{I}\\)\u003c/span\u003e\u003c/span\u003e values indicate elevated weight-bearing asymmetry and compromised postural stability.\u003c/p\u003e\u003cp\u003e\u003cb\u003eHurst Exponent.\u003c/b\u003e The Hurst exponent (\u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\(\\:H\\)\u003c/span\u003e\u003c/span\u003e) characterizes long-range correlations in COP time-series data through Rescaled Range (\u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\(\\:R/S\\)\u003c/span\u003e\u003c/span\u003e) analysis.\u003c/p\u003e\u003cp\u003e\u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\(\\:R/S\\left(n\\right)=\\frac{R\\left(n\\right)}{S\\left(n\\right)}\\propto\\:{n}^{H}\\)\u003c/span\u003e\u003c/span\u003e (Eq.\u0026nbsp;2)\u003c/p\u003e\u003cp\u003ewhere \u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\(\\:\\text{n}\\)\u003c/span\u003e\u003c/span\u003e represents time-series length, \u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\(\\:R\\left(n\\right)\\)\u003c/span\u003e\u003c/span\u003e the range of cumulative deviations, and \u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\(\\:S\\left(n\\right)\\)\u003c/span\u003e\u003c/span\u003e the standard deviation (SD). The exponent \u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\(\\:\\text{H}\\)\u003c/span\u003e\u003c/span\u003e is obtained as the slope of the linear regression between \u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\(\\:\\text{l}\\text{o}\\text{g}(R/S)\\)\u003c/span\u003e\u003c/span\u003e and \u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\(\\:\\text{l}\\text{o}\\text{g}\\left(n\\right)\\)\u003c/span\u003e\u003c/span\u003e. An \u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\(\\:H\\)\u003c/span\u003e\u003c/span\u003e value of 0.5 indicates uncorrelated random walk dynamics, \u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\(\\:H\\)\u003c/span\u003e\u003c/span\u003e \u0026gt;0.5 indicates persistent trends, and \u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\(\\:H\\)\u003c/span\u003e\u003c/span\u003e \u0026lt; 0.5 reflects anti-persistent behavior. Analysis utilized a stabilized 10-second window from the mid-portion of vertical pressure data to exclude transient postural adjustments.\u003c/p\u003e\u003cp\u003e\u003cem\u003eEnvironmental Controls\u003c/em\u003e​​\u003c/p\u003e\u003cp\u003eAll tests were conducted in a climate-controlled laboratory (22–24°C, 40–60% humidity) to standardize environmental influences on biomechanical measurements.\u003c/p\u003e\u003cp\u003e\u003cb\u003eStatistical Analysis​\u003c/b\u003e​\u003c/p\u003e\u003cp\u003eData analysis was conducted using SPSS 29.0 (IBM Corp., USA). Descriptive statistics were first applied to characterize bilateral arch height, hallux valgus angle, and calcaneal inclination angle, and results were expressed as mean ± SD for continuous variables and frequency distributions for categorical measures. Missing data (\u0026lt; 5%) were addressed through mean imputation to preserve dataset integrity.\u003c/p\u003e\u003cp\u003eTo systematically examine associations between arch morphology and biomechanical parameters, a series of regression models were constructed. For the analysis of continuous variables, four simple linear regression models were developed, using unilateral arch height (mm) as the independent variable predicting ipsilateral hallux valgus angle (°) or calcaneal inclination angle (°). Two additional models evaluated bilateral arch height differences (mm) as predictors of sagittal plane center-of-gravity displacement and coronal plane mediolateral pressure center deviation.\u003c/p\u003e\u003cp\u003eCategorical analyses employed dummy-coded arch types (reference: normal arch = 0; flatfoot = 1; flatfoot + = 2; flatfoot++ = 3; high-arched = 4) across eight multivariate linear regression models. Four models predicted ipsilateral hallux valgus angles and calcaneal inclination angles, while the remaining four assessed AEIs and PRR. For CAI and Hurst exponent analyses, two mixed-effects models incorporated both categorical predictors (arch type concordance: 0 = concordant, 1 = discordant) and continuous variables (bilateral arch height differences).\u003c/p\u003e\u003cp\u003eAll models utilized the Enter method and included sex as a covariate to conrol for potential confounding effects. Multicollinearity diagnostics confirmed acceptable variance inflation factors (\u003cem\u003eVIF\u003c/em\u003e \u0026lt; 3.128). Model performance was evaluated using multiple metrics, including \u003cem\u003eR\u003c/em\u003e², adjusted \u003cem\u003eR\u003c/em\u003e², standard error, F-statistics, unstandardized coefficients (\u003cem\u003eB\u003c/em\u003e), standardized coefficients (Beta), 95% CI, and significance levels (\u003cem\u003eP\u003c/em\u003e values).\u003c/p\u003e\u003cp\u003eA priori power analysis conducted in G*Power 3.1 determined a minimum sample size of 146 for multivariate linear regression (effect size \u003cem\u003ef²\u003c/em\u003e = 0.15, \u003cem\u003eα\u003c/em\u003e = 0.05, power = 0.90, 6 predictors). The final cohort (\u003cem\u003eN\u003c/em\u003e = 1078) provided 7.4-fold excess power, ensuring the robust detection of clinically meaningful effects. All hypothesis tests employed two-tailed evaluation with significance threshold set at \u003cem\u003eP\u003c/em\u003e value of \u0026lt; 0.05.\u003c/p\u003e"},{"header":"RESULTS","content":"\u003cp\u003e\u003cb\u003eMorphological Characteristics of the Arch\u003c/b\u003e\u003c/p\u003e\u003cp\u003eDescriptive statistics were used to analyze arch height, hallux valgus angle, and heel valgus angle by laterality and sex (Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e). The distribution of left arch types was as follows: high arch 4.2% (male, 4.6%; female: 3.7%), normal arch 31.9% (male, 35.9%; female, 27.5%), flatfoot 21.1% (male, 19.7%; female, 22.6%), flatfoot\u0026thinsp;+\u0026thinsp;21.2% (male, 17.2%; female, 25.5%), and flatfoot\u0026thinsp;+\u0026thinsp;+\u0026thinsp;21.7% (male, 22.7%; female, 20.6%). For the right foot, the proportions were as follows: high arch, 4.7%; normal arch, 34.9%; flatfoot, 22.9%; flatfoot+, 17.9%; and flatfoot++, 19.6%. Regarding hallux valgus, 56.2% of left feet and 64.1% of right feet exhibited valgus deformity (15\u0026deg; \u0026lt; X\u0026thinsp;\u0026le;\u0026thinsp;30\u0026deg;). A higher prevalence was observed in females for the right foot (66.4% vs. 62.0% in males). For the heel valgus, 34.2% of left feet and 41.6% of right feet were classified as standard, and females showed a higher incidence of left heel valgus (30.3% vs. 23.2% in males). The consistency rate of arch types between left and right feet was 55.9% (male, 57.3%; female, 54.4%), and the average arch height difference was 1.15\u0026thinsp;\u0026plusmn;\u0026thinsp;1.00 mm (male, 1.18\u0026thinsp;\u0026plusmn;\u0026thinsp;1.02 mm; female, 1.12\u0026thinsp;\u0026plusmn;\u0026thinsp;0.98 mm). The consistency rate for hallux valgus was 64.0%, and the average angle difference was 6.38\u0026thinsp;\u0026plusmn;\u0026thinsp;6.16\u0026deg; (male, 6.56\u0026deg; \u0026plusmn; 6.19\u0026deg;; female, 6.17\u0026deg; \u0026plusmn; 6.13\u0026deg;). The consistency rate for heel valgus was 54.6%, with an average angle difference of 4.12\u0026deg; \u0026plusmn; 3.51\u0026deg; (male, 4.14\u0026deg; \u0026plusmn; 3.50\u0026deg;; female, 4.11\u0026deg; \u0026plusmn; 3.53\u0026deg;).\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003e\u003cb\u003eHallux Valgus Angle​\u003c/b\u003e​\u003c/p\u003e\u003cp\u003eArch morphology showed significant laterality-specific biomechanical regulation of hallux valgus (Supplementary Table\u0026nbsp;1). In the left foot continuous model, arch height was negatively correlated with hallux valgus angle in a nonlinear fashion (\u003cem\u003eB\u003c/em\u003e\u0026thinsp;=\u0026thinsp;\u0026minus;\u0026thinsp;1.105, 95% CI [\u0026minus;\u0026thinsp;1.324, \u0026minus;\u0026thinsp;0.886], \u003cem\u003eP\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.001). Each millimeter increase in arch height decreased the valgus angle by 1.1\u0026deg;, although the model\u0026rsquo;s explanatory power was limited (\u003cem\u003eR\u003c/em\u003e\u0026sup2; = 8.4%). The categorical model revealed effect size exponentially increased with the degree of morphological deformation: the effect sizes for flatfoot (\u003cem\u003eB\u003c/em\u003e\u0026thinsp;=\u0026thinsp;14.928), flatfoot+ (\u003cem\u003eB\u003c/em\u003e\u0026thinsp;=\u0026thinsp;15.664), flatfoot++ (\u003cem\u003eB\u003c/em\u003e\u0026thinsp;=\u0026thinsp;18.080), and high arch (\u003cem\u003eB\u003c/em\u003e\u0026thinsp;=\u0026thinsp;35.303) showed a 2.36-fold gradient (\u003cem\u003eP\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.001), and the model accounted for 76.2% of the variation. A similar trend was observed for the right foot, although the effect size was considerably reduced, and the high arch effect (\u003cem\u003eB\u003c/em\u003e\u0026thinsp;=\u0026thinsp;11.129) was only 31.5% of the left foot's effect (\u003cem\u003eP\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.001). Additionally, the upper limit of the 95% CI for the left high arch (36.875\u0026deg;) exceeded the lower limit for the right foot (8.833\u0026deg;), suggesting that anatomical asymmetry induced unilateral compensatory mechanisms (Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003e).\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003e\u003cb\u003eHeel Valgus Angle\u003c/b\u003e\u003c/p\u003e\u003cp\u003eChanges in arch structure elicited bidirectional regulation of heel 3D biomechanics (Supplementary Table\u0026nbsp;1). In the left foot continuous model, arch height showed a strong negative correlation with heel valgus angle (\u003cem\u003eB\u003c/em\u003e\u0026thinsp;=\u0026thinsp;\u0026minus;\u0026thinsp;2.447, \u003cem\u003eP\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.001), accounting for 82.8% of the variance, which indicated that a 1 mm decrease in arch height led to a 2.45\u0026deg; increase in heel valgus. The categorical model demonstrated a graded response in biomechanical effects due to morphological deformation: flatfoot (\u003cem\u003eB\u003c/em\u003e\u0026thinsp;=\u0026thinsp;5.582), flatfoot+ (\u003cem\u003eB\u003c/em\u003e\u0026thinsp;=\u0026thinsp;8.943), and flatfoot++ (\u003cem\u003eB\u003c/em\u003e\u0026thinsp;=\u0026thinsp;15.412) exhibited a 2.76-fold difference in effect size (\u003cem\u003eP\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.001), whereas high arch showed a correction of 8.66\u0026deg; inversion (\u003cem\u003eB\u003c/em\u003e\u0026thinsp;=\u0026thinsp;\u0026minus;\u0026thinsp;8.659, \u003cem\u003eP\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.001). The analysis of the right foot revealed similar trends, but showed a 12.3% reduction in effect size. The effect for flatfoot++ (\u003cem\u003eB\u003c/em\u003e\u0026thinsp;=\u0026thinsp;13.272) surpassed the left foot\u0026rsquo;s normal arch baseline. Additionally, the SD value of the change in heel valgus angle for the left foot (3.01\u0026deg;) was significantly higher than that for the right foot (2.76\u0026deg;), and the largest laterality difference was observed in flatfoot++ (Δ\u003cem\u003eB\u003c/em\u003e\u0026thinsp;=\u0026thinsp;2.14\u0026deg;, 95% CI [1.89, 2.39]; Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003e).\u003c/p\u003e\u003cp\u003e\u003cb\u003eArch Height Difference and Stability\u003c/b\u003e\u003c/p\u003e\u003cp\u003eAsymmetry in bilateral arches considerably affected postural stability, exhibiting a dose-response relationship (Supplementary Table\u0026nbsp;2). Regression analysis showed that for every 1 mm increase in arch height difference, center of mass displacement increased by 10.725 mm (95% CI [10.067, 11.383]) and the left\u0026ndash;right pressure center misalignment increased by 1.58 mm (95% CI [1.476, 1.684]), with a strength ratio of 6.8:1 (\u003cem\u003eβ\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.698 vs. 0.672). These finding suggests that sagittal plane stability is easily influenced by arch asymmetry. Bivariate visualization further revealed that when arch height difference exceeded 3.2 mm, 95% of individuals experienced pressure misalignment exceeding the 5 mm clinical risk threshold. Arch height differences of \u0026ge;\u0026thinsp;5 mm elicited a 18.6% nonlinear increase in center of mass displacement. The difference in the width of the CI between the two models (1.32 mm vs. 0.21 mm) reflected strong compensatory interference in the sagittal plane, providing dual criteria for personalized orthotics based on spatial sensitivity and mechanical determinism (Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003e).\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003e\u003cb\u003eArch Elasticity Index (AEI)\u003c/b\u003e\u003c/p\u003e\u003cp\u003eArch morphological deformities led to a systematic reduction in energy storage function (Supplementary Table\u0026nbsp;3). In the left foot categorical model, flatfoot\u0026thinsp;+\u0026thinsp;+\u0026thinsp;reduced AEI by 62.371 (95% CI [\u0026minus;\u0026thinsp;63.379, \u0026minus;\u0026thinsp;61.363]), which corresponded to 38.7% of the energy storage function of a normal arch (\u003cem\u003eP\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.001). Right foot analysis showed a similar trend, but the high arch effect was diminished by 9.8% (\u003cem\u003eB\u003c/em\u003e\u0026thinsp;=\u0026thinsp;\u0026minus;\u0026thinsp;37.356 vs. \u0026minus;41.859). The pyramid chart revealed that left foot deformation caused considerable elastic damage. The laterality difference for flatfoot\u0026thinsp;+\u0026thinsp;+\u0026thinsp;reached 0.48 SD values (Cohen's \u003cem\u003ed\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.48), and 95% CI (\u0026minus;\u0026thinsp;0.52, \u0026minus;\u0026thinsp;0.44) entirely deviated from zero (Fig.\u0026nbsp;\u003cspan refid=\"Fig5\" class=\"InternalRef\"\u003e5\u003c/span\u003e). The effect size gradient across all deformity types followed a distinct pattern. Flatfoot++ (\u003cem\u003ed\u003c/em\u003e\u0026thinsp;=\u0026thinsp;2.01) demonstrated the greatest biomechanical impact, followed by flatfoot+ (\u003cem\u003ed\u003c/em\u003e\u0026thinsp;=\u0026thinsp;1.35), high arch (d\u0026thinsp;=\u0026thinsp;0.98), and flatfoot (d\u0026thinsp;=\u0026thinsp;0.62).\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003e\u003cb\u003ePressure Recovery Rate (PRR)​​\u003c/b\u003e\u003c/p\u003e\u003cp\u003eArch structural integrity is crucial for shock absorption (Supplementary Table\u0026nbsp;3). In the left foot, flatfoot\u0026thinsp;+\u0026thinsp;+\u0026thinsp;reduced PRR by 0.513 (95% CI [\u0026minus;\u0026thinsp;0.518, \u0026minus;\u0026thinsp;0.507]), indicating that only 51.3% of the normal arch function remained (\u003cem\u003eP\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.001). Right foot analysis showed that flatfoot+ (\u003cem\u003eB\u003c/em\u003e\u0026thinsp;=\u0026thinsp;\u0026minus;\u0026thinsp;0.308) and high arch (\u003cem\u003eB\u003c/em\u003e\u0026thinsp;=\u0026thinsp;\u0026minus;\u0026thinsp;0.312) had comparable effect sizes, suggesting that lateral arch damage led to equivalent functional loss. The absolute effect size for left foot PRR damage (mean Δ\u0026thinsp;=\u0026thinsp;0.307) was considerably higher than that for the right foot (Δ\u0026thinsp;=\u0026thinsp;0.291; Fig.\u0026nbsp;\u003cspan refid=\"Fig5\" class=\"InternalRef\"\u003e5\u003c/span\u003e). Temporal analysis revealed that the half-life of the left foot pressure recovery curve increased by 23.6% (\u003cem\u003eP\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.001).\u003c/p\u003e\u003cp\u003e\u003cb\u003eCoordination Asymmetry Index (CAI)​​\u003c/b\u003e\u003c/p\u003e\u003cp\u003eArch abnormalities induced compensatory imbalance in bilateral pressure distribution (Supplementary Table\u0026nbsp;4). Left foot flatfoot\u0026thinsp;+\u0026thinsp;+\u0026thinsp;increased CAI by 0.302 (\u003cem\u003eP\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.001), equivalent to 3.2 SD of normal arch pressure asymmetry. Right foot high arch had the strongest effect (\u003cem\u003eB\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.341, \u003cem\u003eP\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.001), with its 95% CI (0.277, 0.406) fully covering the left foot flatfoot\u0026thinsp;+\u0026thinsp;+\u0026thinsp;range [0.251, 0.353]. The effect size of bilateral arch type differences (\u003cem\u003eB\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.41, \u003cem\u003eP\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.001) was 15.8 times that of the height difference (\u003cem\u003eB\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.026), accounting for 59.6% of the model\u0026rsquo;s explanatory power. Additionally, the asymmetry effect for left foot deformities (mean \u003cem\u003eB\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.212) was significantly higher than for the right foot (\u003cem\u003eB\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.170), and the effect strength of type differences increased logarithmically with the degree of deformity (\u003cem\u003eR\u003c/em\u003e\u0026sup2; = 0.872; Fig.\u0026nbsp;\u003cspan refid=\"Fig6\" class=\"InternalRef\"\u003e6\u003c/span\u003e).\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003e\u003cb\u003eHurst Exponent​​\u003c/b\u003e\u003c/p\u003e\u003cp\u003eChanges in arch structure remodeled the long-term stability of pressure distribution (Supplementary Table\u0026nbsp;4). Left foot flatfoot\u0026thinsp;+\u0026thinsp;+\u0026thinsp;decreased the Hurst index by 0.21 (95% CI [\u0026minus;\u0026thinsp;0.233, \u0026minus;\u0026thinsp;0.188]), indicating a 37.2% reduction in long-term correlation of pressure time series (\u003cem\u003eP\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.001). In contrast, right foot high arch produced a positive modulation of 0.133 (\u003cem\u003eP\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.001), with the effect direction being mirror-symmetric to that of the left foot (\u003cem\u003er\u003c/em\u003e\u0026thinsp;=\u0026thinsp;\u0026minus;\u0026thinsp;0.786, \u003cem\u003eP\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.002). The bilateral arch height difference was negatively correlated with the Hurst index (\u003cem\u003eB\u003c/em\u003e\u0026thinsp;=\u0026thinsp;\u0026minus;\u0026thinsp;0.023, \u003cem\u003eP\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.001), attenuating 38.7% of the positive effects of type differences. Furthermore, the stability damage for left foot deformities was pronounced. The laterality difference (ΔB) for flatfoot\u0026thinsp;+\u0026thinsp;+\u0026thinsp;was 0.09 (95% CI [0.07, 0.11]), and the effect size gradient following a power law distribution (\u003cem\u003eR\u003c/em\u003e\u0026sup2; = 0.943; Fig.\u0026nbsp;\u003cspan refid=\"Fig6\" class=\"InternalRef\"\u003e6\u003c/span\u003e).\u003c/p\u003e"},{"header":"DISCUSSION​","content":"\u003cp\u003e\u003cb\u003eMechanisms of Arch Variations in Forefoot Bony Deformities\u003c/b\u003e\u003c/p\u003e\u003cp\u003eThis study identified a considerably modulatory effect of that arch structure on hallux valgus angle, especially in the left foot. Regression analysis revealed that for each 1 mm decrease in left arch height was associated with a 1.105\u0026deg; increase in hallux valgus angle (\u003cem\u003eB\u003c/em\u003e\u0026thinsp;=\u0026thinsp;\u0026minus;\u0026thinsp;1.105, \u003cem\u003eP\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.001). This finding is highly consistent with the strong correlation proposed by Eustace et al.\u003csup\u003e13\u003c/sup\u003e between medial longitudinal arch angle and the first metatarsal rotation (\u003cem\u003er\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.93). The classification models showed that the hallux valgus angle in the left foot flatfoot\u0026thinsp;+\u0026thinsp;+\u0026thinsp;group reached 18.08\u0026deg;, which significantly higher than that observed in the normal arch group (\u003cem\u003eP\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.001). This result corroborates the pathological mechanism through which arch collapse leads to first metatarsal internal rotation (pronation) and subsequent axis deviation of the first metatarsal\u003csup\u003e13,14\u003c/sup\u003e.\u003c/p\u003e\u003cp\u003eNotably, the high-arch group exhibited an abnormal increase in the left foot hallux valgus angle to 35.303\u0026deg;, which markedly exceeded that of the flatfoot\u0026thinsp;+\u0026thinsp;+\u0026thinsp;group. This finding aligns with that of Steadman et al.\u003csup\u003e14\u003c/sup\u003e, where high-arched feet adopt a compensatory pronation mechanism. In such cases, forefoot load is concentrated on the first and second metatarsal heads. Pressure concentration is exacerbated in females because of their smaller shoe sizes, leading to increased medial pressure peaks and structural deformities\u003csup\u003e4\u003c/sup\u003e. The \u0026ldquo;U-shaped curve\u0026rdquo; observed in this study (flatfoot and high arch worsen hallux valgus) underscores the need to reframe clinical management strategies. Rather than adopting a \u0026ldquo;flatfoot-centric\u0026rdquo; approach, clinical assessment ann intervention should incorporate the biomechanical evaluation of high-arched feet.\u003c/p\u003e\u003cp\u003eThe relationship in the right foot was weak (continuous model \u003cem\u003eB\u003c/em\u003e\u0026thinsp;=\u0026thinsp;\u0026minus;\u0026thinsp;0.483, \u003cem\u003eP\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.001) possibly because of the enhanced muscular compensation ability of the dominant foot. Data showed that the hallux valgus angle in the right foot high-arch group (11.129\u0026deg;) was significantly lower than that in the left foot (35.303\u0026deg;), and gender differences were small (male 7.9% vs. female 6.5%). These results corroborates the hypothesis of Yang et al.\u003csup\u003e15\u003c/sup\u003e, which suggests that muscle control on the dominant side serves as a buffering mechanism against deformation.\u003c/p\u003e\u003cp\u003e\u003cb\u003eMechanisms of Arch Variations on Rearfoot Tilt\u003c/b\u003e\u003c/p\u003e\u003cp\u003eThe strong correlation between arch collapse and rearfoot eversion was especially prominent in the left foot. The continuous model showed that a 1 mm decrease in arch height resulted in 2.45\u0026deg; increase in rearfoot eversion (\u003cem\u003eB\u003c/em\u003e\u0026thinsp;=\u0026thinsp;\u0026minus;\u0026thinsp;2.447, \u003cem\u003eP\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.001). This result aligns with Eustace\u0026rsquo;s model\u003csup\u003e13\u003c/sup\u003e on the synergistic motion theory of calcaneal eversion, where the collapse of the medial longitudinal arch causes internal rotation at the subtalar joint and ultimately leads to an exponential increase in calcaneal eversion angle (with flatfoot\u0026thinsp;+\u0026thinsp;+\u0026thinsp;group rearfoot eversion reaching 15.412\u0026deg;). The anatomical mechanism can be explained as follows: Arch collapse results in loss of tension in the posterior tibial and spring ligament complex, causing the calcaneus to evert because of the loss of medial support\u003csup\u003e16\u003c/sup\u003e. Meanwhile, a change in the plantar fascia pull direction further exacerbates rearfoot line deviation\u003csup\u003e17\u003c/sup\u003e.\u003c/p\u003e\u003cp\u003eBy contrast, the high arch group exhibited an inverse mechanism, and the left foot calcaneal inversion angle reached \u0026minus;\u0026thinsp;8.659\u0026deg; (\u003cem\u003eP\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.001). This change may be to an increase in plantar fascia angle (PFA). Jiang et al.\u003csup\u003e17\u003c/sup\u003e suggests that an increase in PFA in high-arched feet leads to a lateral shift in the calcaneal load-bearing zone (particularly at the base of the fifth metatarsal), causing stress concentration on the lateral column and forcing the calcaneus to invert to maintain balance. Changes in the right foot were small (continuous model \u003cem\u003eB\u003c/em\u003e\u0026thinsp;=\u0026thinsp;\u0026minus;\u0026thinsp;2.252 vs. left foot \u0026minus;\u0026thinsp;2.447). In the classification model, the rearfoot eversion in the flatfoot\u0026thinsp;+\u0026thinsp;+\u0026thinsp;group still reached 13.272\u0026deg;, suggesting differences in bilateral compensation mechanisms.\u003c/p\u003e\u003cp\u003e\u003cb\u003eImpact of Arch Asymmetry on Postural Control and Neurological Regulation\u003c/b\u003e\u003c/p\u003e\u003cp\u003eThis study found a considerable relationship between arch asymmetry and postural stability. Regression analysis showed a 1 mm increase in the difference in arch height between the left and right feet elicits a 10.725 mm shift in the center of gravity (\u003cem\u003eB\u003c/em\u003e\u0026thinsp;=\u0026thinsp;10.725, \u003cem\u003eP\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.001), and the mediolateral center of pressure deviation increased by 1.58 mm (\u003cem\u003eB\u003c/em\u003e\u0026thinsp;=\u0026thinsp;1.58, \u003cem\u003eP\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.001). These findings are consistent with those of Mandal et al.\u003csup\u003e18\u003c/sup\u003e, who concluded that arch differences disrupt proprioceptive input by causing asymmetric pressure distribution and amplify errors in spinal cord and cerebellar postural regulation. The finite element model of Peng\u003csup\u003e19\u003c/sup\u003e further confirms this mechanism. Arch differences alter the synergistic activation pattern of the posterior tibial and fibular longus muscles, thus reducing the efficiency of the lower limb kinetic chain and increasing the central nervous system\u0026rsquo;s burden for postural control.\u003c/p\u003e\u003cp\u003eGu et al.\u003csup\u003e20\u003c/sup\u003e clinically validated this mechanism. After correcting arch differences with Scarf osteotomy combined with subtalar joint stabilization, follow-up after one year showed considerable improvements in HVA, IMA, Meary\u0026rsquo;s angle, calcaneal tilt angle, and talocalcaneal angle (\u003cem\u003eP\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.001). This finding suggests that restoring bilateral mechanical balance through arch reconstruction can enhance neuromuscular regulation efficiency.\u003c/p\u003e\u003cp\u003e\u003cb\u003eRegulation of Elastic Energy Storage Systems by Arch Variations\u003c/b\u003e\u003c/p\u003e\u003cp\u003eThis study found a considerable effect of abnormal arch morphology on the foot\u0026rsquo;s elastic energy storage function. In the left foot flatfoot\u0026thinsp;+\u0026thinsp;+\u0026thinsp;group, the AEI decreased by 62.371 units (\u003cem\u003eB\u003c/em\u003e\u0026thinsp;=\u0026thinsp;\u0026minus;\u0026thinsp;62.371, \u003cem\u003eP\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.001), and the PRR decreased by 0.513 units (\u003cem\u003eB\u003c/em\u003e\u0026thinsp;=\u0026thinsp;\u0026minus;\u0026thinsp;0.513, \u003cem\u003eP\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.001), indicating that arch collapse disrupts energy metabolism through dual mechanisms: (1) Plantar Fascia Dysfunction: The overstretched plantar fascia loses pre-tension capacity because of excessive elongation\u003csup\u003e21\u003c/sup\u003e, leading to a considerable decline in elastic potential energy storage. This mechanism aligns with that described by Cifuentes-De la Portilla et al.\u003csup\u003e22\u003c/sup\u003e, who demonstrated that arch collapse reduces proximal plantar fascial stress while amplifying distal strain. (2) Compensatory Tendon Overload: Posterior tibial tendon hyperactivation concentrates pressure on the medial forefoot, further impairing energy return efficiency during push-off\u003csup\u003e5\u003c/sup\u003e.\u003c/p\u003e\u003cp\u003eHigh-arched individuals exhibited a significant decrease in AEI (left foot \u003cem\u003eB\u003c/em\u003e\u0026thinsp;=\u0026thinsp;\u0026minus;\u0026thinsp;41.859, \u003cem\u003eP\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.001), which is related to the lack of shock absorption in rigid arches. The kinematic data of Kruger et al.\u003csup\u003e2\u003c/sup\u003e showed that high-arched individuals have peak rearfoot inversion angles of 13.6\u0026deg; \u0026plusmn; 4.6\u0026deg;, which limits the deformability of the arch, and shock forces are directly transmitted through the calcaneus to the knee joint. These data aligns with the findings of Ledoux et al.\u003csup\u003e1\u003c/sup\u003e, who demonstrated increased pressure peaks at the metatarsal heads in high-arched individuals with diabetic foot.\u003c/p\u003e\u003cp\u003e\u003cb\u003eImpact of Arch Asymmetry on Gait Coordination and Dynamic Stability\u003c/b\u003e\u003c/p\u003e\u003cp\u003eArch asymmetry considerably influences gait coordination and dynamic stability. A one-level increase in the difference in arch type between the left and right feet led to 0.41 increase in CAI (\u003cem\u003eB\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.41, \u003cem\u003eP\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.001). In addition, the Hurst exponent decreased by 0.019 units (\u003cem\u003eB\u003c/em\u003e\u0026thinsp;=\u0026thinsp;\u0026minus;\u0026thinsp;0.019, \u003cem\u003eP\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.007), indicating that arch differences lead to disordered gait pressure distribution and increased randomness. In the left foot flatfoot\u0026thinsp;+\u0026thinsp;+\u0026thinsp;group, CAI reached 0.302 (\u003cem\u003eP\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.001), suggesting an imbalance in pressure distribution between the medial forefoot and lateral rearfoot. This finding corresponds to the conclusions of Imhauser et al.\u003csup\u003e5\u003c/sup\u003e, whose in vitro model demonstrated that posterior tibial tendon dysfunction leads to a posterior shift in the pressure center, forcing abnormal loading on the medial forefoot and disrupting the sequential transmission of gait forces. The decrease in the Hurst exponent (left foot flatfoot\u0026thinsp;+\u0026thinsp;+\u0026thinsp;group \u003cem\u003eB\u003c/em\u003e\u0026thinsp;=\u0026thinsp;\u0026minus;\u0026thinsp;0.21, \u003cem\u003eP\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.001) reflects the increased compensatory burden on the central nervous system, which must adjust through high-frequency muscle activation to maintain balance. This finding aligns with that of Menz et al.\u003csup\u003e3\u003c/sup\u003e, who proposed the \u0026ldquo;foot dysfunction\u0026ndash;spinal compensation\u0026rdquo; hypothesis stating that foot dysfunction potentially leads to an increased risk of knee valgus and low back pain in the long term\u003csup\u003e4\u003c/sup\u003e. By contrast, the high-arched group exhibited an abnormal increase in the Hurst exponent (right foot \u003cem\u003eB\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.133, \u003cem\u003eP\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.001), indicating gait rhythm stiffening and reduced dynamic adaptability, further supporting the conclusion of Kruger et al.\u003csup\u003e2\u003c/sup\u003e regarding the deterioration of kinematic stability in high-arched individuals.\u003c/p\u003e\u003cp\u003e\u003cb\u003eSports Practice and Clinical Rehabilitation Implications​\u003c/b\u003e​\u003c/p\u003e\u003cp\u003eThe identified associations between arch abnormalities and multifactorial biomechanical dysfunction underscore critical applications in sports training and clinical rehabilitation.\u003c/p\u003e\u003cp\u003e\u003cem\u003eAthletic Training Considerations\u003c/em\u003e​​\u003c/p\u003e\u003cp\u003eIncorporating arch morphology screening (height, symmetry, and elasticity index) into pre-participation assessments facilitates targeted injury prevention. For flatfoot individuals, evidence-based interventions should emphasize intrinsic foot muscle strengthening through short-foot exercises. Cheng et al.\u003csup\u003e23\u003c/sup\u003e reported considerably improvement navicular drop test outcomes after six-week regimens. High-arched individuals require prioritized ankle mobility training and footwear with enhanced midfoot cushioning to alleviate lateral column stress concentrations. This recommendation is consistent with the observations of Kruger et al.\u003csup\u003e2\u003c/sup\u003e regarding compensatory hindfoot inversion mechanics.\u003c/p\u003e\u003cp\u003e\u003cem\u003eClinical Rehabilitation Strategies\u003c/em\u003e​​\u003c/p\u003e\u003cp\u003ePersonalized orthotic prescriptions must integrate dynamic pressure mapping, particularly for cases with bilateral height disparities of \u0026gt;\u0026thinsp;3.2 mm and CAI of \u0026gt;\u0026thinsp;0.3. Gu et al.\u003csup\u003e20\u003c/sup\u003e combined Scarf osteotomy and subtalar arthroereisis protocol to achieve significant mechanical normalization (\u003cem\u003eP\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.001). Although artificial intelligence\u0026ndash;driven orthosis design shows promise, overreliance on static parameters risks suboptimal load redistribution\u003csup\u003e24\u003c/sup\u003e. Hence, clinicians should monitor neuromechanical sequelae: Menz et al.\u003csup\u003e3\u003c/sup\u003e linked foot dysfunction to 48% increase in low-back pain risk in females (OR\u0026thinsp;=\u0026thinsp;1.48). Winkelmann et al.\u003csup\u003e4\u003c/sup\u003e associated 1.9 mm navicular drop increases with 23% increase in MTSS incidence. Integrating plantar sensory augmentation and cortical feedback mechanisms may counteract arch-mediated postural degradation, especially in older cohorts and those with neurological disorders, who are prone to falls.\u003c/p\u003e\u003cp\u003e\u003cb\u003eLimitations and Future Directions​\u003c/b\u003e​\u003c/p\u003e\u003cp\u003eThis study advances understanding of arch biomechanics, but several limitations warrant consideration. The exclusive focus on 18\u0026ndash;25-year-old university students restricts generalizability across developmental stages and aging populations, underscoring the need for the recruitment adolescents and older adults to capture lifespan-related arch adaptations. Methodologically, reliance on static parameters overlooks dynamic functional responses. This gap should be addressed through the multimodal integration of 3D gait analysis, force plate kinetics, and surface electromyography into the formulation of map load redistribution patterns during locomotion\u003csup\u003e25,26\u003c/sup\u003e. Although cross-sectional associations are robust, causation remains inferential. The longitudinal tracking of arch deterioration trajectories and randomized controlled trials assessing orthotic or surgical interventions would strengthen mechanistic claims. The observed left-foot predominance in structural alterations highlights the need for neurophysiological exploration through functional MRI and transcranial magnetic stimulation to unravel central sensorimotor compensation mechanisms in dominant limbs. Collectively, these directions may transform static morphological descriptions into dynamic and clinically actionable models of foot function.\u003c/p\u003e"},{"header":"CONCLUSION","content":"\u003cp\u003eThis study, grounded in a large sample size, comprehensive biomechanical metrics, and robust statistical modeling, systematically elucidates the complex relationships between foot arch morphology and key functional parameters of the foot and lower limb. Our findings reveal that reduced and elevated arch heights can cause structural deformities, such as forefoot malalignment and calcaneal eversion, through distinct mechanisms. Additionally, bilateral arch asymmetry considerably impairs postural control and proprioceptive feedback, elevating the risk of postural instability. Abnormal arch morphology markedly diminishes the foot\u0026rsquo;s elastic energy storage capacity, compromising gait efficiency and altering plantar responses to ground reaction forces. These insights not only advance the theoretical understanding of the biomechanical coupling between arch structure and foot function but also provide critical parameters for injury prevention, sports screening, rehabilitation design, and the development of intelligent intervention systems. We advocate for the broader adoption of foot arch assessments across diverse age groups and pathological populations and their integration into dynamic monitoring and longitudinal follow-up strategies. Such efforts will facilitate a shift from static structural analyses to dynamic functional optimization, offering data-driven support and technological foundations for precision sports medicine and smart rehabilitation.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eEthics Approval and Consent to Participate\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThis study was approved by the Ethics Committee of the School of Physical Education, Jimei University, and conducted in accordance with the principles of the Declaration of Helsinki. Written informed consent was obtained from all 1078 university student participants from Jimei University prior to enrollment.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConsent for Publication\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eNot applicable. This manuscript does not contain personally identifiable data, images, or videos from any individual.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAvailability of Data and Materials\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eData is provided within the manuscript or supplementary information files.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eCompeting Interests\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe authors declare no competing financial or non-financial interests. The funders had no role in study design, implementation, or manuscript preparation.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eFunding\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThis work was supported by the National Social Science Fund of China [Grant Number 23TYB00862].\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAuthor Contributions\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eConceptualization: X.W., J.Y.; Methodology: Z.X., Y.L., Y.C.; Investigation: Z.X., Y.L., L.Y.; Data Curation: Y.C., L.Y.; Writing—Original Draft: Z.X., Y.L.; Writing—Review \u0026amp; Editing: Z.X., Y.L., X.W., J.Y.; Resources: X.W., J.Y.; Supervision: X.W., J.Y.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAcknowledgements\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eWe sincerely thank the 1078 university students from Jimei University for their participation and all research collaborators for their invaluable contributions. Special recognition is given to the students whose dedication was fundamental to this study's success.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eClinical Trial Number\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eClinical trial number: not applicable.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n\u003cli\u003eLedoux WR, Shofer JB, Ahroni JH, Smith DG, Sangeorzan BJ, Boyko EJ. Biomechanical differences among pes cavus, neutrally aligned, and pes planus feet in subjects with diabetes. \u003cem\u003eFoot Ankle Int\u003c/em\u003e. 2003;24(11):845-850. doi:10.1177/107110070302401107\u003c/li\u003e\n\u003cli\u003eKruger KM, Graf A, Flanagan A, et al. Segmental foot and ankle kinematic differences between rectus, planus, and cavus foot types. \u003cem\u003eJ Biomech\u003c/em\u003e. 2019;94:180-186. doi:10.1016/j.jbiomech.2019.07.032\u003c/li\u003e\n\u003cli\u003eMenz HB, Dufour AB, Riskowski JL, et al. 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Kinetic characteristics of high-arched feet during running stance phase. \u003cem\u003eJ Phys Educ\u003c/em\u003e. 2017;24(2):122-127. doi:10.16237/j.cnki.cn44-1404/g8.20170121.002\u003c/li\u003e\n\u003cli\u003eEustace S, Byrne JO, Beausang O, et al. Hallux valgus, first metatarsal pronation and collapse of the medial longitudinal arch\u0026mdash;a radiological correlation. \u003cem\u003eSkeletal Radiol\u003c/em\u003e. 1994;23(3):191-194. doi:10.1007/BF00197458\u003c/li\u003e\n\u003cli\u003eSteadman J, Barg A, Saltzman CL. First metatarsal rotation in hallux valgus deformity. \u003cem\u003eFoot Ankle Int\u003c/em\u003e. 2021;42(4):510-522. doi:10.1177/1071100721997149\u003c/li\u003e\n\u003cli\u003eYang F, Wu C, Wang J, et al. Subtalar arthroereisis for simultaneous treatment of flexible pes planus during surgical correction of hallux valgus. \u003cem\u003eEur J Med Res\u003c/em\u003e. 2025;30(1):44. doi:10.1186/s40001-025-02299-8\u003c/li\u003e\n\u003cli\u003eWong YS. Influence of the abductor hallucis muscle on the medial arch of the foot: a kinematic and anatomical cadaver study.\u003cem\u003e Foot Ankle Int\u003c/em\u003e. 2007;28(5):617-620. doi:10.3113/FAI.2007.0617\u003c/li\u003e\n\u003cli\u003eJiang Z, Zhang Q, Ren L, et al. Non-invasive and quantitive analysis of flatfoot based on ultrasound. \u003cem\u003eFront Bioeng Biotechnol\u003c/em\u003e. 2022;10:961462. doi:10.3389/fbioe.2022.961462\u003c/li\u003e\n\u003cli\u003eMandal S, Mandal P, Basu R. Study of variations in the medial longitudinal arch leading to development of adult acquired flat foot. \u003cem\u003eInt J Med Pharm Sci\u003c/em\u003e. 2013;5(3):12-18.\u003c/li\u003e\n\u003cli\u003ePeng Y. Biomechanical study of adult acquired flatfoot for intervention. \u003cem\u003eJ Biomech Eng\u003c/em\u003e. 2022;144(7):071006. doi:10.1115/1.4054156\u003c/li\u003e\n\u003cli\u003eGu W, Fu S, Wang C, et al. Outcomes of simultaneous correction of adult hallux valgus and flexible pes planus deformities. \u003cem\u003eOrthopedics\u003c/em\u003e. 2025;48(1):37-43. doi:10.3928/01477447-20241213-03\u003c/li\u003e\n\u003cli\u003eYamamoto H, Muneta T, Asahina S, et al. Forefoot pressures during walking in feet afflicted with hallux valgus. \u003cem\u003eClin Orthop Relat Res\u003c/em\u003e. 1996;(323):247-253.\u003c/li\u003e\n\u003cli\u003eCifuentes-De la Portilla C, Larrainzar-Garijo R, Bayod J. Biomechanical stress analysis of the main soft tissues associated with the development of adult acquired flatfoot deformity. \u003cem\u003eClin Biomech (Bristol)\u003c/em\u003e. 2019;61:163-171. doi:10.1016/j.clinbiomech.2018.12.009\u003c/li\u003e\n\u003cli\u003eCheng J, Han D, Qu J, et al. Effects of short foot training on foot posture in patients with flatfeet: a systematic review and meta-analysis. \u003cem\u003eJ Back Musculoskelet Rehabil\u003c/em\u003e. 2024;37(3):839-851. doi:10.3233/BMR-230226\u003c/li\u003e\n\u003cli\u003eHoang NTT, Chen S, Chou LW. The impact of foot orthoses and exercises on pain and navicular drop for adult flatfoot: a network meta-analysis. \u003cem\u003eInt J Environ Res Public Health\u003c/em\u003e. 2021;18(15):8063. doi:10.3390/ijerph18158063\u003c/li\u003e\n\u003cli\u003eBai XT, Huo HF. Biomechanical evaluation of foot and ankle function: constructing static and dynamic assessment indicators. \u003cem\u003eChin J Tissue Eng Res\u003c/em\u003e. 2021;25(17):2747-2754.\u003c/li\u003e\n\u003cli\u003eLiu J, Deng M, Wang W, et al. A foot structure study of new arch flexibility grading system based on three-dimensional arch volume. \u003cem\u003eChin J Traumatol\u003c/em\u003e. 2023;26(5):329-333. doi:10.1016/j.cjtee.2023.09.002\u003c/li\u003e\n\u003c/ol\u003e\n\u003cp\u003e\u0026nbsp;\u003c/p\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":true,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"scientific-reports","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"scirep","sideBox":"Learn more about [Scientific Reports](http://www.nature.com/srep/)","snPcode":"","submissionUrl":"","title":"Scientific Reports","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"stoa","reportingPortfolio":"Scientific Reports","inReviewEnabled":true,"inReviewRevisionsEnabled":true},"keywords":"Foot arch morphology, Sports injury, Biomechanics, Hallux valgus, Calcaneal Angle Index, Postural stability, Plantar pressure, Hurst index","lastPublishedDoi":"10.21203/rs.3.rs-7090359/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-7090359/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003e\u003cstrong\u003eObjective:\u003c/strong\u003e This study aimed to investigate the relationship between foot arch structure and lower limb biomechanical parameters and to quantify the effects of arch morphology on postural stability, plantar pressure distribution, foot elasticity, and related structural deformities.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eMethods:\u003c/strong\u003e A cross-sectional study was conducted involving 1078 university students (569 males and 509 females; mean age = 20.18 ± 1.43 years). The iFEET Neo 3D system was used to measure arch height, hallux valgus angle, and calcaneal angle, whereas the iGAIT MAX 3D system assessed plantar pressure distribution, center of gravity displacement, mediolateral pressure center deviation, arch elasticity index (AEI), and pressure recovery rate (PRR). A Kistler force platform (Model 9286B) was used to calculate the coordination asymmetry index (CAI) and the Hurst exponent of the center of pressure trajectory. Multivariate linear regression and mixed-effects models were employed to examine the associations between foot arch type and the measured biomechanical parameters.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eResults: \u003c/strong\u003eArch height demonstrated significant association with multiple biomechanical indicators. Individuals with high arches exhibited a marked increase in hallux valgus angle (\u003cem\u003eB \u003c/em\u003e= 35.303, \u003cem\u003eP \u003c/em\u003e\u0026lt; 0.001), and each 1 mm decrease in arch height was associated with a 2.45° increase in calcaneal eversion (\u003cem\u003eB\u003c/em\u003e = –2.447, \u003cem\u003eR\u003c/em\u003e² = 0.828) and a considerable increase in CAI. A 1 mm increase in bilateral arch height difference corresponded to a 10.7 mm shift in the center of gravity and a 1.58 mm mediolateral displacement in the pressure center (\u003cem\u003eP\u003c/em\u003e \u0026lt; 0.001). Reduced arch height was associated with a marked decline in foot elastic function; specifically, AEI decreased by 62.4 points in the flatfoot++ group (95% confidence interval: –63.379, –61.363), accompanied by a corresponding reduction in PRR. The Hurst exponent deviated significantly from 0.5 in individuals with abnormal foot structures, indicating decreased dynamic postural stability.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConclusion:\u003c/strong\u003e Abnormal foot arch morphology is closely associated with the impaired biomechanical function of the foot, including reduced postural stability, diminished energy storage and return capacity, and angular deformities. These findings provide a quantitative foundation for injury risk identification and functional foot assessment, and support the integration of arch structure screening into student health management programs.\u003c/p\u003e","manuscriptTitle":"Biomechanical Correlates between Foot Arch Morphology and Sports Injury Risks: a Multifactorial Analysis of 1078 University Students","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-07-16 08:49:40","doi":"10.21203/rs.3.rs-7090359/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"decision","content":"Revision requested","date":"2025-12-11T07:28:20+00:00","index":"","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-12-08T13:06:46+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"181493815208430182390001379204555312948","date":"2025-12-04T13:57:14+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"6334939337236825594878590968457393611","date":"2025-12-04T12:24:59+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"88049110138858372891925807510833055910","date":"2025-10-03T13:18:58+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-07-21T08:23:32+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"298316482374737383356905070222179106562","date":"2025-07-19T14:30:52+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"200047141010491558277140995974281560910","date":"2025-07-16T12:20:47+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"148720968773092058659626414769326419207","date":"2025-07-15T09:41:30+00:00","index":"hide","fulltext":""},{"type":"reviewersInvited","content":"","date":"2025-07-14T11:47:29+00:00","index":"","fulltext":""},{"type":"editorInvited","content":"","date":"2025-07-14T09:58:57+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2025-07-11T06:47:29+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2025-07-11T02:55:21+00:00","index":"","fulltext":""},{"type":"submitted","content":"Scientific Reports","date":"2025-07-10T07:51:14+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"scientific-reports","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"scirep","sideBox":"Learn more about [Scientific Reports](http://www.nature.com/srep/)","snPcode":"","submissionUrl":"","title":"Scientific Reports","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"stoa","reportingPortfolio":"Scientific Reports","inReviewEnabled":true,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"380f178c-9329-426d-949a-2229eae6d5c4","owner":[],"postedDate":"July 16th, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"published-in-journal","subjectAreas":[{"id":51555709,"name":"Health sciences/Anatomy"},{"id":51555710,"name":"Health sciences/Diseases"},{"id":51555711,"name":"Health sciences/Health care"},{"id":51555712,"name":"Health sciences/Medical research"},{"id":51555713,"name":"Health sciences/Risk factors"}],"tags":[],"updatedAt":"2026-02-09T16:01:04+00:00","versionOfRecord":{"articleIdentity":"rs-7090359","link":"https://doi.org/10.1038/s41598-026-38118-1","journal":{"identity":"scientific-reports","isVorOnly":false,"title":"Scientific Reports"},"publishedOn":"2026-02-05 15:57:42","publishedOnDateReadable":"February 5th, 2026"},"versionCreatedAt":"2025-07-16 08:49:40","video":"","vorDoi":"10.1038/s41598-026-38118-1","vorDoiUrl":"https://doi.org/10.1038/s41598-026-38118-1","workflowStages":[]},"version":"v1","identity":"rs-7090359","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-7090359","identity":"rs-7090359","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}