STEM1

Overview

In this project, a simulation was conducted to analyze the effects of fluid-integrated shoes on plantar pressure redistribution. By reducing high-pressure regions along the plantar surface of the foot, the simulation demonstrated the feasibility of water-based integration as a method for mitigating foot edema.

Abstract

Foot swelling, or edema, is a common physiological response to strenuous or prolonged physical activities. The swelling is caused by excess fluids from the body accumulating in the feet, leading to discomfort, reduced stability, and an increased risk of injury. Individuals with reduced vascular efficiency, such as older adults, people with obesity, or those with circulatory challenges, are especially prone to the risks of foot edema, making daily activities challenging and potentially dangerous. To address this problem, this project assesses how integrating fluid chambers into everyday shoes can reduce activity-induced foot edema by redistributing the pressure along the plantar surface of the foot. The buildup of fluids in the foot is a direct effect of increased stress on the foot, so by redistributing the pressure of high-pressure areas on the foot, the need for these fluids is reduced. By utilizing ANSYS, a leading company in developing engineering simulation software, a simulation was developed to assess the theoretical possibility of using fluids to redistribute the force exerted onto the foot to even out the high-pressure areas. The simulation results indicate reduced pressure in high-impact areas, spreading the force towards the middle of the foot. These findings assisted in determining the feasibility and structures of fluid chambers within the shoe, suggesting overall, the fluid-based shoe systems have the potential to reduce foot strain and mitigate foot edema. If validated through physical testing, this concept could improve comfort and safety during everyday activities, particularly to populations more prone to foot edema.

Phrase 1

Physical activities, especially strenuous or drawn-out ones, can cause a buildup of fluid in the lower extremities that causes the afflicted region to swell up, which is called activity-induced edema (Lin et al., 2012).

Phrase 2

The primary objective of this project is to design a device that incorporates fluids into shoes and determine how the device can affect activity-induced edema.

Background Infographic

Background

Project Description The primary objective of this project is to design a device that incorporates fluids into everyday shoes and determine how the device can affect activity-induced foot edema. Using ANSYS simulations, the theoretical effectiveness of fluid-integration will be assessed, and then the optimal layout of fluid chambers will be decided. Once the layout of chambers is finalized, a prototyped design will be created and tested. While wearing fluid-integrated shoes, participants will engage in standing, walking, jogging, and sprinting activities. The practical effectiveness and comfort of the shoes will then be evaluated by measuring the foot edema caused by the activity using the water displacement method (King, 1993) and asking subjective questions to the participants after the activity. The results of the test will then be compared to the results of similar tests using standard shoes to determine whether the integration of fluids into shoes can reduce foot edema and improve comfort in daily activities. Background and Significance While mild foot edema is commonly observed among most individuals, severe occurrences are typically seen among people who have decreased vascular efficiency within their bodies, such as people who are older, overweight, or have circulatory problems (Cloughley & Mawdsley, 1995). In the United States, this statistic is particularly concerning because the rising obesity rates are shown to be closely related to foot edema (Burian et al., 2024), with one study showing that approximately 80% of individuals with obesity suffer from some form of edema, ranging from mild, harmless swelling to chronic foot edema, which means their swelling is long-term rather than temporary (Keast et al., 2014). As a result, people with vascular deficiencies are more prone to injuries and discomfort from everyday activities such as standing and walking. These negative effects highlight the need for strategies to mitigate foot edema. Plantar Pressure Foot edema is caused by a buildup of fluids in the foot, which, in most cases, is caused by prolonged activities that cause certain areas in the foot to receive a higher-pressure load than others, causing more tissue strain. This pressure system along the bottom of the foot at any given time is called plantar pressure. It is commonly uneven, with the highest pressure typically occurring under the heel and the ball of the foot.

Figure #1

Plantar pressure distribution imported from the experimental dataset and mapped onto the foot contact surface in ANSYS.

Figure #2

Figure 11: Contact pressure distribution at the foot–insole interface after deformation of a conventional solid polyurethane insole.

Analysis

Barefoot conditions concentrate stress at discrete heel and forefoot regions, producing high local pressure maxima. Standard insoles redistribute load slightly, but localized pressure concentrations persist due to the uniform elastic response of solid materials. Fluid-integrated designs reduce peak pressures by redistributing force laterally and increasing the effective contact area, which lowers localized tissue stress and may decrease swelling risk during prolonged activity. However, these findings are comparative and require experimental validation because of the simplified geometry and material assumptions used in the simulation.

Discussion/Conclusions

Finite-element simulations using experimentally derived plantar-pressure inputs suggest that fluid-integrated insoles can reduce peak plantar pressure compared to standard footwear designs.

These results suggest that fluid-integrated footwear has significant potential to mitigate activity-induced foot edema by redistributing pressure across the plantar surface, providing a strong foundation for further research in this field.

References

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