This study investigates the dynamic breast response of nine representative breast types by finite element method, focusing on the effects of breast volume, running speed, and nipple spatial configuration. The simulation revealed that greater breast volume and higher speed significantly increased displacement and acceleration (p < 0.001). The volume and speed were key predictors of breast motion in both Y- and Z-directions, while nipple position type modulated lateral dynamics. Notably, middle-type breasts exhibited greater lateral stability. These findings offer biomechanical insights into breast movement, and provide basis for the design of sports bras tailored to different breast morphologies.

Compression leggings act as external bio-functional supports that enhance postural stability and gait performance. This study developed a subject-specific three-dimensional Finite Element (FE) model of the female lower body to investigate the biomechanical interactions between compression leggings and underlying tissues, focusing on interface pressure, soft tissue deformation, and intramuscular stress. A distinctive and comprehensive methodology reconstructed anatomically accurate geometries from high-resolution Magnetic Resonance Imaging data to segment nine major muscle groups. Region-specific hyperelastic properties were assigned from in vivo indentation tests, and orthotropic fabric properties were characterised through uniaxial tension and shear testing. FE simulations revealed non-uniform responses: interface pressure decreased from the calf to the low hip before increasing at the high hip, with higher anterior pressures linked to anatomical curvature. Tissue deformation peaked at the high hip and was minimal at the calf, while muscle stress reflected tissue stiffness and pressure, with the highest values in the calf anterior. These findings inform biomechanics-oriented design strategies, where gradient compression and fabrics with varied elasticity, anisotropic stretch, or engineered knits are optimised to align with local tissue properties and curvature. Model predictions agreed with experimental measurements (errors: 15.4

Arch morphology significantly affects plantar pressure distribution and load-bearing balance, and appropriate insole support can improve plantar load distribution. This study developed insoles for high- and lowarched feet by varying the medial-lateral arch height difference. Finite element analysis was performed to evaluate peak plantar pressure and plantar contact area. The optimal designs were identified as (-10, 5 mm) for high-arched feet and (-10, 0 mm) for low-arched feet. These findings provide a preliminary basis for the parametric design of arch-specific insoles and personalized orthotic insole design under static standing conditions.

This study aimed to investigate the effects of different saddle height setting methods and fatigue on lower limb kinematics during indoor cycling in recreational cyclists. Twelve recreational male cyclists completed indoor cycling randomly using three saddle height setting methods-trochanteric length method (TLM), LeMond method (LMM) and knee angle method (KAM)-performed a fatigue protocol. Sagittal-plane ankle, knee and hip kinematic data were collected. Extracted ankle, knee and hip angles at top dead center (TDC), bottom dead center (BDC) and range of motion (ROM) for data analysis. A two-way repeated-measures ANOVA was conducted to examine the main effects of saddle height, fatigue and their interaction. This study found that saddle height setting methods significantly influenced ankle and knee kinematics. Compared with KAM and LMM, TLM resulted in greater ankle (p = 0.01) and knee (p = 0.01) ROM, as well as reduced knee flexion at TDC (p = 0.01) and reduced knee extension at BDC (p = 0.01). Fatigue significantly reduced ankle (p = 0.02) and hip (p = 0.01) angles at TDC but did not affect knee kinematics. A significant saddle height & times; fatigue interaction was observed only for hip range of motion (p = 0.04), with a post-fatigue increase occurring exclusively under LMM condition. Saddle height setting methods substantially influence lower-limb kinematics during cycling, while fatigue induces joint-specific adaptations. Recreational cyclists should consider that different setting methods produce distinct effective heights that influence joint responses to fatigue.

Objective This study proposes an AI-enhanced modular material selection approach for designing diabetic insoles. By customizing materials for forefoot and heel modules, the method enables personalized support and pressure redistribution, resulting in cost-effective insoles. Background Diabetic foot ulcers occur as a result of elevated plantar pressure and poor foot sensation. To mitigate this risk, developing insoles that redistribute plantar pressure can significantly lower the likelihood of ulcer formation. Method The insole was fabricated using cost-effective silicone molding, with functional personalization achieved via an AI-enhanced approach that selected optimal, interchangeable cushioning materials for forefoot and heel modules of each patient. The design integrates a ¾-length porous silicone upper layer with regionally optimized materials. Laboratory wear trials involving 23 diabetic patients compared the offloading performance of the hybrid insole (AIO) against barefoot, a PORON® Medical 4708 insole (PUR), and a cork-EVA insole (EVA). Results AIO demonstrated a 37.6% reduction in peak plantar pressure compared to barefoot condition while increasing contact area by 36.0% across the plantar surface. It significantly outperformed the commercial insole (EVA) and matched a therapeutic insole (PUR) overall, with superior regional offloading at the heel. Conclusion This study enhances diabetic foot care by combining efficiency of silicone molding with functionally personalized, modular design to achieve superior pressure redistribution. It establishes a paradigm of “modular personalization” for diabetic insoles, leveraging AI for patient-specific material selection within a standardized, biomechanically optimized geometry. Application The findings offer practical insights for clinicians and manufacturers seeking scalable, patient-specific solutions for preventing diabetic foot ulcers.

Compression textiles have been widely applied in medical, sportswear, and daily usage, with single-jersey structures produced by circular knitting dominating the market due to their thinness and light weight. However, the presence of seams may compromise compression performance and wearer comfort. This study investigates the effects of yarn type, number of yarns, and loop length on pressure, stretchability, and thermal comfort of seamless punch-lace knitted fabrics and explores their potential application in compression textiles. The results show that yarn number is the dominant factor influencing fabric stiffness, stretchability, and pressure. Fabrics with increased yarn content demonstrate higher maximum load and compression pressure. Smaller loop lengths and additional reinforcing yarns improve dimensional stability and resistance to extension. Air permeability decreases with increasing yarn number due to increased fabric thickness and reduced porosity, while thermal conductivity increases and is positively associated with ventilation resistance, indicating a trade-off between heat transfer and breathability. Surface friction and roughness are significantly affected by yarn number, yarn type, and loop length, whereas water vapour permeability shows no significant relationship with the investigated variables. Overall, seamless punch-lace knitted fabrics demonstrate strong potential for compression applications, although careful design is required to balance breathability and thermal comfort.

The current study investigated the impact of facial three-dimensional shape geometry and respirator-face interface mechanics on the fit of N95 respirators in 21 Hong Kong Chinese adults. Three-dimensional facial scanning, quantitative fit testing of four N95 respirators (3M 1860, 1870+, 9105, and 9502+), and facial dimensions extraction using Geomagic Wrap were conducted in this study. The seven fit test exercises were performed in the current investigation, while finite element analysis (FEA) was used for studying respirator-face contact mechanics in a stratified subset of 14 participants wearing 3M 1870+ geometry. Among all evaluated models, 3M 1870+ had the highest pass rate. Pearson correlation analysis showed only nominal, uncorrected associations between the fit factor and nose length (r = 0.574, p = 0.007) as well as neck circumference (r = 0.434, p = 0.050). None of the anthropometric correlations remained statistically significant after Bonferroni correction for multiple comparisons (n = 38) (adjusted alpha level = 0.00132). Threshold post hoc observations of the bitragion coronal arc, neck circumference, nose height and nose length should therefore be considered as hypothesis generation and not as screening criteria. Fit factors decreased in dynamic movements, especially when bending. FEA-predicted contact area correlated strongly with experimental fit factor (r = 0.974, 95% CI: 0.918 to 0.992, p < 0.001), thus confirming the association of simulation and fit performance measurement but not serving as independent validation of the model. These preliminary results could be helpful for future respirator fit studies and respirator design for Hong Kong Chinese adults.

This study aimed to investigate the impact of different types of compression legwear on knee biomechanics, and lower limb inter-joint coordination during depth jumps. Twelve healthy male participants were randomly assigned to wear compression shorts (CS), compression tights (CT), and sports shorts (control: CC). The participants perform depth jumps from a platform of 40 cm in height, thus landing on their dominant side (DS) and non-dominant side (NS). The lower limbs kinematics and kinetics are simultaneously recorded by using a motion capture system and force plates. During initial contact phase, the CT group shows larger peak knee flexion angles (PI = 0.033) and sagittal knee range of motion (ROM) (PIII = 0.010) but smaller horizontal ROM of the knee (PIII = 0.016) than the CC group. During stabilization phase, the CS group exhibits significantly higher peak knee flexion (PII = 0.025) and sagittal knee ROM (PII = 0.001). While the peak vertical ground reaction force (vGRF) is not obtained by the type of legwear (P > 0.05), significant phase- and direction-specific differences emerge in the knee moments, with the CS group showing larger extension moments in landings on the DS (PI < 0.001, PII = 0.005) but smaller abduction moments than the CC/CT in landings on the NS (PII = 0.004). An inter-joint coordination analysis indicates that the CT group has the highest knee-ankle (P < 0.001) and knee-hip coordination (P < 0.001) during landing on the NS, whereas the CC group shows excellent knee-hip coordination on the DS (P < 0.001). Compression legwear exerts pressure on the lower limbs during various phases of jumping, thereby altering the biomechanical characteristics of the knee joint and the synergistic mechanisms of the lower limbs. CT improve knee-ankle coordination and mediolateral stability, while CS enhance sagittal-plane control during bilateral landings.

Sports bras knitted with high-Young’s modulus materials are effective in reducing the range of breast movement (ROM), but also increase the contact pressure to the body, leading to discomfort or even body injury. Elasticity distribution was found to be a factor influencing both pressure and ROM, however, the mechanism has yet to be studied, limiting its application in the sports bra industry. This study aimed to investigate the quantitative relationships between Young’s modulus of different parts (C, S f , S b , B, U) and the performance metrics of sports bras in pressure and ROM for the optimization of both performance. A finite element (FE) model was developed to simulate the dynamic peak pressure at four test points and ROM for sports bras with different elasticity distributions during exercise. Based on which, a regression model was formed and the sensitivity factors (φ) were ranked through 2 5 full factorial analysis. The results revealed that the influence of Young’s modulus of each part varied with the pressure test points and the directions of ROM. Notably, the effect on pressure varied based on the placement of the test point relative to the part of sports bra. P 1 , P 2 , and P 4 were greatly influenced by Young’s modulus of the part covering the test point and the parts nearby, whereas P 3 was mainly influenced by U. The effect on ROM predominantly depended on S f , C, and U rather than S b and B. Therefore, the elasticity distribution design with relatively low S b and B, relatively high S f and U, and appropriate C was recommended to optimize both performances. These findings provide novel information for optimizing pressure comfort and breast support performance of sports bras, which is hoped to sever as a valuable reference for sports bra industry.

This study presents an advanced dynamic finite element (FE) model of multiple components of the breast to examine the biomechanical impact of different types of physical activities and activity intensity on the breast tissues. Using 4D scanning and motion capture technologies, dynamic data are collected during different activities. The accuracy of the FE model is verified based on relative mean absolute error (RMAE), and optimal material parameters are identified by using a validated stepwise grid search method. The comparative analysis reveals that jumping rope generates the highest stress on the breast components, followed by high knee skipping but running exerts the least amount of stress. A positive correlation between activity intensity and stress is observed for running and jumping rope, while high knee skipping shows a peak in stress after a certain threshold. The magnitude of the stress distribution and effect of activity intensity on the stress experienced by the breast internal components are in ascending order: the glandular tissues, pectoralis major muscles, adipose tissues, and Cooper’s ligaments, thus highlighting the different biomechanical response of these breast components to dynamic stress. The insights from this study have significant implications for sports bra design, rehabilitation protocols, and exercise customisation with the aim to reduce the risk of injury during breast motion.

Lattice structures have been widely studied in various fields due to their lightweight and high-energy absorption capabilities. In this study, we propose the use of lattice structures in the design of sports protective equipment for contact sports athletes. A total of six specimens were additively manufactured either with a bending-dominated rhombic dodecahedron (RD) structure or stretch-dominated re-entrant (RE) structure. Elastic resin was used to investigate the specimens’ compressive strength and energy absorption, impact reduction, and flexural properties in comparison with those of conventional foam and rigid polyethylene (PU). Despite having a lower relative density, the RE structure exhibits greater stiffness, showing up to 40% greater hardness and averaging 30.5% higher bending rigidity compared with the RD structure. However, it unexpectedly shows less stability and strength under uniaxial loading, which is 3 to 6 times weaker when compared with the non-auxetic RD structure. Although conventional PU has higher loading than 3D-printed lattices, the lattice shows excellent bendability, which is only 1.5 to 3 times stiffer than that of foam. The 3D-printed lattice in this study shows an optimal improvement of 43% in terms of impact absorption compared with foam and a 2.3% improvement compared with PU. Amongst the six different unit cell dimensions and structures studied, the RD lattice with a cell size of 5 mm is the most promising candidate; it has superior elasticity, compressive strength, and impact resistance performance whether it is under low- or high-impact conditions. The findings of this study provide a basis for the development of 3D-printed lattice sports protective chest equipment, which is more comfortable and offers improved protection for contact sports players.

This study aimed to investigate the biomechanical variations among different types of foot arches. Plantar pressure and foot bone stress of three arch types under bipedal standing, single foot standing and running mid-stance were investigated by simulation. Compared with the normal foot, the stress in the hind foot area of high arch foot increased significantly, while the contact area of the low arch foot increased. Bone stress in high arch increased more significantly when changed from bipedal standing to single foot standing or running. The results support the link between abnormal arches and foot pain, providing design basis for orthopedic insoles.

Bracing is a widely used conservative treatment for adolescent idiopathic scoliosis (AIS) patients, yet there is no consensus on the optimal amount of force applied. Although a number of different sensors have been developed to continuously monitor the applied pressure and force, they have several limitations, including inadequate overall force distribution and displacement. They also cause discomfort with limited wearability. In this study, body pressure mapping knitwear (BPMK) integrated with fourteen silicone-embedded fiber Bragg grating (FBG) sensors is developed to monitor immediate and overall changes in force during the bracing treatment. A wear trial of the BPMK is conducted by using a validated soft AIS mannequin, and prediction equations have been formulated for the FBG sensors at individual locations. The findings indicate that the measured forces are in good agreement with those obtained from clinical studies, with peak forces around the padding regions reaching approximately 2N. This was further validated by using finite element (FE) models. When comparing X-ray images, the estimated differences in Cobb angles were found to be 0.6° for the thoracic region and 2.1° for the lumbar region. This model is expected to provide valuable insights into optimal force application, thus minimizing the risk of injury and enhancing bracing compliance and efficacy. Ultimately, this innovative approach provides clinicians with data-driven insights for safer and more effective bracing applications, thus improving the quality of life of AIS patients.

Arch structure is a crucial interface between the human body and the ground during landing tasks, but the biomechanical effects of arch support stiffness remain insufficiently explored. This study examines the effects of arch supports with different stiffnesses on lower-limb biomechanics during landing. Twelve male participants (six normal arches, six flat feet) performed a single-leg drop landing from a 45 cm height under four arch support conditions: no arch support pad (NAP), soft-stiffness arch support pad (SAP), medium-stiffness arch support pad (MAP), and high-stiffness arch support pad (HAP). Dominant lower-limb joint angles and moments in the sagittal plane and vertical ground reaction force (vGRF)-related parameters—time to peak vGRF, peak vGRF, and max loading rate—were recorded using a motion capture system and force plate. Data were analyzed using one-way repeated measures analysis of variance (ANOVA). Arch pad stiffness significantly affected ankle and knee kinematics. The NAP condition exhibited significantly higher ankle plantarflexion at initial contact (p ≤ 0.01), as well as larger range of motion (ROM) of the knee (p = 0.03) and hip (p < 0.01), compared to the use of a SAP or MAP. The use of a HAP resulted in a significantly lower peak ankle dorsiflexion moment and larger peak knee flexion angle than the other conditions (p ≤ 0.04). The peak knee extension moment was the highest when using a NAP, and was significantly higher than that shown with the use of a MAP or HAP (p ≤ 0.02). No significant differences were observed in hip joint moments or vGRF-related parameters across conditions (p ≥ 0.52). These results indicate that hard-stiffness arch support pads modulate lower-limb mechanics during landing, potentially enhancing shock absorption and reducing knee loading.

In the early stage of bra pattern making, the gore size is an important design feature to provide different effects such as enhancing the shape of the breasts and the depth of the cleavage, as well as affecting the fitting issue. However, the shaping effects in controlling the breast shape of the gore size have not been investigated in previous studies. This study proposes a finite element method (FEM) to simulate the effect of gore dimensions on breast shape in a wired-bra. A biomechanical model based on accurate geometries and mechanical properties of humans is first built. Then, the sub-model of a bra with different gore design scenarios interacts with the sub-model of the human body. A factorial analysis has been conducted that the effects of lengths of the upper gore and lower gore on the breast geometry are systematically investigated based on the numerical contact models. The length of the upper gore positively contributes to the gathering of the breasts and a deeper cleavage. While the length of the lower gore has a negative relationship with the lifting effect of the breasts and the position of the bra underwire. Reduced lower gore length would lead to a poor fit of the underwire against the breast roots. The method proposed in this paper can be used by bra designers to predict the breast deformation, and thus reducing the time required for the designing of pattern making at the early stages.

This study explores the biomechanical impact of an elliptical leaf spring (ELS) foot on individuals with unilateral below-knee amputation. The ELS-foot, constructed with carbon fiber leaf springs and an ethylene-vinyl acetate rocker bottom sole, aims to balance energy storge and dissipation for effective cushioning and energy management. Six participants were recruited and visited the laboratory twice within a 3-to-5-day interval. The ELS-foot is compared with their own prosthesis through various mobility and balance tests, including the Timed Up and Go test, Four Square Step Test, 10 m walk test, Berg Balance Test, eyes-closed standing test, Tandem Test, jumping and walking test, and a subjective evaluation. Passive-reflective markers are placed on the participants according to the plug-in full body model. An eight-camera motion capture system synced with two force plates mounted under a walkway is used for the gait analysis. The results show that participants move faster during the Four Square Step Test and demonstrate better balance during the eyes-closed standing test and Tandem Test and jump higher with the ELS-foot. The unique ELS-foot design mechanism and rocker bottom sole facilitates better energy transfer and stability, thus enhancing the postural stability. These findings offer valuable insights for future prosthetic technology advancements.

Background: Compression garments (CG) may influence countermovement jump (CMJ) performance by altering hip and knee biomechanics, but existing evidence remains controversial. This study aimed to compare the effects of compression tights (CTs), compression shorts (CSs), and control shorts (CCs) on CMJ performance and lower-limb biomechanics. Methods: Nine physically active men from a university were recruited to perform CMJ while wearing CTs, CSs, and CCs in a randomized sequence for a within-subjects repeated-measures design. A Vicon 3D motion capture system and an AMTI 3D force plate were used to collect biomechanical data. Visual3D software was used to calculate the joint angle, moment, and force of the lower limbs. Results: Statistical parametric mapping analysis with repeated measures analysis of variance (ANOVA) revealed that during the propulsion phase of the CMJ, wearing CSs significantly reduced the hip flexion angle compared to wearing CCs (25-36%); meanwhile, wearing CTs significantly reduced the knee extension and flexion moment (34-35%) and decreased the hip extension moment during the propulsion phase (36-37%). In addition, CTs significantly reduced the hip abduction angle during the flight phase (37-39%), and CSs significantly reduced the hip anterior force during the landing phase (59-60%). Conclusions: Compression legwear significantly affected the hip and knee biomechanics in propulsion, but these differences were not sufficient to improve the CMJ height. Due to the improvement in hip biomechanics in the flight and landing phases, there may be potential benefits for movement transitions and landing performance in CMJ.

The development of adaptive and comfortable sports bras is essential for adolescents, who experience rapid changes in body morphology during growth. Traditional bras, often made with molded polyurethane bra pads, frequently fail to accommodate these variations, leading to discomfort and poor fit. This study investigates the design of a flexible-fit bra utilizing advanced knitting technology and bio-based materials, including organic cotton and renewable acetate, to enhance comfort and adaptability. The bra, crafted from bio-based yarns, offers stretchability, breathability, and fit, allowing it to adapt to various breast shapes and sizes. Such a bra design is particularly suitable for adolescents undergoing rapid growth. This study includes assessments of material properties and user feedback to evaluate the effectiveness of the design and identify areas for improvement. Positive results were reported from both material tests and subjective evaluations, confirming the effectiveness of the design. The seamless knitting minimizes irritation, while the inlay spacer fabric absorbs impact, and the pointelle structure improves moisture management. Adjustable components enhance adaptability and ensure a flexible fit. This study highlights the potential of knitted biomaterials for creating adaptive intimate apparel, offering a scalable solution for size-inclusive fashion.

Compression stockings have long been manufactured in a single color without patterns, but enhancing their aesthetic appeal through knitted designs can improve user compliance. This study explores the potential of punch lace knitted structures to create patterns in compression textiles by seamless knitting technology while maintaining sufficient pressure. The effects of yarn material, number of yarns used, and knitted patterns on pressure and thermal comfort will be studied. The fabric pressure was evaluated using pressure sensors with a leg mannequin, while the thermal properties were measured according to the textile standard. This study found that the pressure and thermal conductivity of fabric are significantly influenced by the number of yarn and yarn materials, but not the knitted pattern. Cupro/cotton/polyurethane yarn (A) exhibits the strongest positive impact on pressure, increasing by 2.03 mmHg with the addition of one end of yarn A while polyamide/lycra yarn (C) exhibits a higher thermal conductivity than yarn A. For air permeability, the number of yarn and knitted patterns significantly affects the ventilation resistance. Pattern B with an additional needle in a float stitch shows 0.023 kPa·s/m lower resistance than pattern A. The findings from this study can be widely used in health, medical, and sports applications.