Prediction of Dynamic Plantar Pressure from Insole Intervention for Diabetic Patients Based on Patch-based Multilayer Perceptron with Localization Embedding

Li-ying Zhang, Ze-qi Ma, Kit-lun Yick, Pui-ling Li, Joanne Yip, Sun-pui Ng, and Qi-long Liu👋

IEEE Access, 2024-07-10

Assessing plantar pressure is crucial for fabricating diabetic insoles and preventing diabetic foot ulcers (DFUs), which are caused by increased plantar pressure. However, the commonly used methods for assessing plantar pressure distribution involve professional sensor-based equipment and expertise, which are costly and time-consuming. Given the qualitative association between ink footprint images and plantar pressure, this study proposes using the footprint images to predict the quantitative values of dynamic plantar pressure in barefoot and 4 different insole conditions (including Nora Lunalastik EVA, Nora Lunalight A fresh, Pe-Lite, and PORON Medical 4708) based on a multilayer perceptron (MLP) neural network model. To provide more precise insole material recommendations for specific foot regions for better plantar pressure distribution, the plantar of the foot is divided into 5 regions: the toes, metatarsal heads, medial midfoot, lateral midfoot, and heel. Patch-based MLP with localization embedding is introduced to learn the correspondence between ink density and plantar pressure information. Ground-truth data collected from 52 diabetes patients is constructed as a dataset named diabetes-footprint-to-pressure and used to train and validate the model. The mean absolute error (MAE) of the models for the barefoot and 4 insole conditions is 5.51% (33.06 kPa), 3.99% (23.94 kPa), 4.85% (29.10 kPa), 4.25% (25.50 kPa), and 3.57% (21.42 kPa) of the sensing range, respectively. Compared to traditional methods for plantar pressure assessment, this approach streamlines the process of acquiring the overall and regional dynamic plantar pressure with barefoot and 4 different insole materials. Clinicians can quickly provide recommendations on the type of insole material for individual patients.

Construction of multi-component finite element model to predict biomechanical behaviour of breasts during running and quantification of the stiffness impact of internal structure

Jia-zhen Chen, Yue Sun, Qi-long Liu👋, Joanne Yip, Kit‐lun Yick

Biomechanics and Modeling in Mechanobiology, 2024-05-28

This study aims to investigate the biomechanical behaviour and the stiffness impact of the breast internal components during running. To achieve this, a novel nonlinear multi-component dynamic finite element method (FEM) has been established, which uses experimental data obtained via 4D scanning technology and a motion capture system. The data are used to construct a geometric model that comprises the rigid body, layers of soft tissues, skin, pectoralis major muscle, fat, ligaments and glandular tissues. The traditional point-to-point method has a relative mean absolute error of less than 7.92% while the latest surface-to-surface method has an average Euclidean distance (d) of 7.05 mm, validating the simulated results. After simulating the motion of the different components of the breasts, the displacement analysis confirms that when the motion reaches the moment of largest displacement, the displacement of the breast components is proportional to their distance from the chest wall. A biomechanical analysis indicates that the stress sustained by the breast components in ascending order is the glandular tissues, pectoralis major muscle, adipose tissues, and ligaments. The ligaments provide the primary support during motion, followed by the pectoralis major muscle. In addition, specific stress points of the breast components are identified. The stiffness impact experiment indicates that compared with ligaments, the change of glandular tissue stiffness had a slightly more obvious effect on the breast surface. The findings serve as a valuable reference for the medical field and sports bra industry to enhance breast protection during motion.

Ultra-dense Motion Capture: An exploratory full-automatic approach for dense tracking of breast motion in 4D

Qi-long Liu👋, Kit-lun Yick, Yue Sun, Joanne Yip

PLOS ONE, 2024-02-26

Understanding the dynamic deformation pattern and biomechanical properties of breasts is crucial in various fields, including designing ergonomic bras and customized prostheses, as well as in clinical practice. Previous studies have recorded and analyzed the dynamic behaviors of the breast surface using 4D scanning, which provides a sequence of 3D meshes during movement with high spatial and temporal resolutions. However, these studies are limited by the lack of robust and automated data processing methods which result in limited data coverage or error-prone analysis results. To address this issue, we identify revealing inter-frame dense correspondence as the core challenge towards conducting reliable and consistent analysis of the 4D scanning data. We proposed a fully-automatic approach named Ulta-dense Motion Capture (UdMC) using Thin-plate Spline (TPS) to augment the sparse landmarks recorded via motion capture (MoCap) as initial dense correspondence and then rectified it with a sophisticated post-alignment scheme. Two downstream tasks are demonstrated to validate its applicability: virtual landmark tracking and deformation intensity analysis. For evaluation, a dynamic 4D human breast anthropometric dataset DynaBreastLite was constructed. The results show that our approach can robustly capture the dynamic deformation characteristics of the breast surfaces, significantly outperforms baselines adapted from previous works in terms of accuracy, consistency, and efficiency. For 10 fps dataset, average error of 0.25 cm on control-landmarks and 0.33 cm on non-control (arbitrary) landmarks were achieved, with 17-70 times faster computation time. Evaluation was also carried out on 60 fps and 120 fps datasets, with consistent and large performance gaining being observed. The proposed method may contribute to advancing research in breast anthropometry, biomechanics, and ergonomics by enabling more accurate tracking of the breast surface deformation patterns and dynamic characteristics.

Construction of multi-component finite element model to predict biomechanical behaviour of breasts during running and quantification of the stiffness impact of internal structure

Qi-long Liu👋

MPhil Thesis, The Hong Kong Polytechnic University, 2024

This thesis presents a comprehensive approach to facilitate breast biomechanics research and ergonomic sports bra design. The study involves three main components: dynamic 4D scanning of the female subject during running, dense tracking of breast deformation, and finite element modeling with material properties fine-tuning using 4D scanning data. The innovative use of 4D scanning technology captures whole-surface information of the human body during dynamic activities, providing high-temporal and spatial resolutions mesh data for analysis. Based on the anthropometric landmarks labelled from the 4D scanning sequence, the overall trajectories and the accumulated regional displacement of the breast soft tissues, as well as the distribution of deformation intensity can be precisely analyzed. Results indicated that the accumulated trajectory lengths of different landmarks range from 50 cm to 80 cm. Of which, the vertical and lateral swinging are the primary movement trends of the breasts during running. The large trajectory differences (48.6%) amongst the landmarks also confirm the highly nonlinear deformation patterns of the breasts during dynamic motion. A robust dense tracking method, the Ultra-dense Motion Capture (UdMC) algorithm, is proposed to capture the dense whole-surface deformation profile of the breasts, advancing the traditional motion capture technology from the sparse landmark level to the dense surface level. Comprehensive evaluation shown that our approach significantly outperforms previous works in accuracy, consistency, and efficiency. With reference to the complete 120 fps dataset, the average errors are found as 0.43cm for the control-landmarks and 0.78cm for the non-control (arbitrary) points. As compared to the traditional approach, the calculation speed of the proposed UdMC algorithm is 40-200 times faster. Lastly, a subject-specific finite element (FE) model is constructed and fine-tuned with the dense deformation profile captured by UdMC, making it capable to align with the realistic breast behavior more reliably. To facilitate efficient determination of the subject-specific Mooney-Rivlin material parameters, the principle parameters inflation scheme was proposed to transform the optimization problem from the 5 dimensional space search to the 2 dimensional space search. This FE breasts model has successfully simulated and predicted the characteristics and response of the breasts when wearing different sports bra with varying design factors, which has significant application value in breasts soft tissue biomechanics research as well as validating and optimizing sports bras prototype designs.

Analysis of Diabetic Foot Deformation and Plantar Pressure Distribution of Women at Different Walking Speeds

Li-ying Zhang, Qi-long Liu👋, Kit-lun Yick, Joanne Yip, Sun-pui Ng

International Journal of Environmental Research and Public Health, 2023-02-19

Official guidelines state that suitable physical activity is recommended for patients with diabetes mellitus. However, since walking at a rapid pace could be associated with increased plantar pressure and potential foot pain, the footwear condition is particularly important for optimal foot protection in order to reduce the risk of tissue injury and ulceration of diabetic patients. This study aims to analyze foot deformation and plantar pressure distribution at three different walking speeds (slow, normal, and fast walking) in dynamic situations. The dynamic foot shape of 19 female diabetic patients at three walking speeds is obtained by using a novel 4D foot scanning system. Their plantar pressure distributions at the three walking speeds are also measured by using the Pedar in-shoe system. The pressure changes in the toes, metatarsal heads, medial and lateral midfoot, and heel areas are systematically investigated. Although a faster walking speed shows slightly larger foot measurements than the two other walking speeds, the difference is insignificant. The foot measurement changes at the forefoot and heel areas, such as the toe angles and heel width, are found to increase more readily than the measurements at the midfoot. The mean peak plantar pressure shows a significant increase at a faster walking speed with the exception of the midfoot, especially at the forefoot and heel areas. However, the pressure time integral decreases for all of the foot regions with an increase in walking speed. Suitable offloading devices are essential for diabetic patients, particularly during brisk walking. Design features such as medial arch support, wide toe box, and suitable insole material for specific area of the foot (such as polyurethane for forefoot area and ethylene-vinyl acetate for heel area) are essential for diabetic insole/footwear to provide optimal fit and offloading. The findings contribute to enhancing the understanding of foot shape deformation and plantar pressure changes during dynamic situations, thus facilitating the design of footwear/insoles with optimal fit, wear comfort, and foot protection for diabetic patients.

Influence of contoured insoles with different materials on kinematics and kinetics changes in diabetic elderly during Gait

Qiu-qiong Shi, Pui-ling Li, Kit-lun Yick, Jiao Jiao, Qi-long Liu👋

International Journal of Environmental Research and Public Health, 2022-09-30

Background: Alterations in the lower limb kinematics and kinetics of diabetic patients have been reported in previous studies. Inappropriate choices of orthopedic insole materials, however, fail to prevent diabetic foot ulcers and modify abnormal gait. The aim of this study was to quantitatively compare the effects of contoured insoles with different materials on the kinematics of and kinetics changes in the diabetic elderly during gait. Methods: There were 21 diabetic patients who participated in this study. Three-dimensional (3D) experimental contoured insoles constructed of soft (i.e., Nora Lunalastik EVA and PORON® Medical 4708) and rigid (i.e., Nora Lunalight A fresh and Pe-Lite) materials with Langer Biomechanics longitudinal PPT® arch pads were adopted. An eight-camera motion capture system (VICON), two force plates, and an insole measurement system—Pedar® with 99 sensors—were utilized to obtain the kinematics and kinetics data. The plug-in lower body gait model landmarks were used for dynamic data acquisition during gait. The corresponding data from five gait cycles were selected and calculated. Results: The range of motions (ROMs) of the ankle joint (p = 0.001) and knee joint (p = 0.044) were significantly influenced when the contoured insoles were worn in comparison to the barefoot condition. The joint moments of the lower limbs with maximum ankle plantarflexion during the loading response and maximum knee and hip flexions were significantly influenced by the use of contoured insoles with different materials in the diabetic elderly. The peak plantar pressure (PPP) of the forefoot (p < 0.001), midfoot (p = 0.009), and rearfoot (p < 0.001) was significantly offloaded by the contoured insoles during the stance phase, whilst the PPP of the rearfoot (p < 0.001) was significantly offloaded during the swing phase. Conclusions: The contoured insoles, especially those constructed with soft materials, significantly offloaded the PPP during gait—hence accommodating certain abnormal gait patterns more effectively compared to going barefoot.

Sports bra pressure: effect on core body temperature and comfort sensation

Qi-long Liu👋, Kit-lun Yick, Kam-ching Chan, Sin-tung Wong, Sun-pui Ng

Applied Human Factors and Ergonomics (AHFE) 2022 International Conference, 2022

Background: Sports bras are engineer designed to enhance sports performance, which means that they need to provide an excellent fit, and offer adequate support and protection of the breasts to optimize their functionality. To effectively reduce breast motion during different intensity levels of exercise, the materials of sports bras are generally rigid which exert compressive forces onto the soft tissues of the breasts. However, these materials may still restrict air flow and inhibit body heat loss, while the pressure from the bra exerted onto the skin may also increases physiological strain and wear discomfort. This excessively high exerted pressure is known to produce an inhibitory effect on the sweating rate and associated with a significant rise in the axillary and core temperatures. This preliminary study therefore investigates the influence of bra pressure on the upper body temperature and thermal comfort following a short duration of treadmill running. Objective: The purpose of this study is to investigate the effect of increased bra pressure on thermal response following exercise. The findings provide bra designers with insight into bra pressure and related bra design features necessary for optimal wear comfort during physical activities. Methods: A total of 12 young women have participated in this study to don a changeable sports bra that allows adjustment of tension or replacement of the bra components. The skin and body core temperatures as well as heart rate for four bra conditions during treadmill running for 15 minutes at 8 km/h are recorded by using temperature and heart rate sensors. The subjectively perceived thermal and pressure comfort are evaluated by using a visual analog scale with ratings of 1 to 10.Results: Following exercise, there is no change in core temperature for all of the bra conditions studied. Even though the body core temperature may increase due to the higher rate of heat production with muscular work done during treadmill running, the increase in heat dissipation tends to balance the increase in rate of metabolic heat production to maintain a stable core temperature. After a short duration of treadmill running, the change in skin temperature ranges from 0.22oC to 3.56oC amongst the 4 bra conditions. The shoulder strap area shows a slight change in skin temperature during exercise, and the participants are particularly sensitive to the increased pressure in this area, thus adversely affecting their ratings of the thermal and pressure comfort. Conclusion: In this study, the increased bra pressure does not show significant change in core temperature and heart rate during short duration exercise. Even though the results are not statistically significant, the shoulder strap pressure is found to be related to the changes in skin temperature and subjective ratings of thermal and pressure comfort.

Construction of experimental teaching system of biomedical engineering for demand of industry

Xi Chen, Qi-long Liu👋, Lei Dong, Hu Tang, Tian-fu Wang, Si-ping Chen

Experimental Technology and Management, 2020

In view of the problems existing in biomedical engineering education, such as the lack of pertinence, disconnection from the needs of the industry and lack of a perfect teaching experimental platform and data system, this paper puts forward a biomedical engineering experimental teaching system for the demand of the industry. The whole process with fine refinement and high efficiency for the biomedical engineering experimental teaching is provided by constructing the experimental teaching platform with the “Three-in-one” integration of the experimental equipment, experimental teaching materials and video resources. The system has the characteristics of modularization, and standardization, and combines closely with the leading-edge concepts of the industry, teaching and research practice, achieving good teaching practice effect and positive feedback.