Principle of plantar pressure collection system for flat foot evaluation
I. Data collection and sensor technology
Pressure sensing mechanism
The system collects pressure values of various areas of the plantar in real time through high-density pressure sensors (such as capacitive and piezoelectric sensors) to generate dynamic/static pressure distribution diagrams. The sensor accuracy can reach millimeter level and can capture abnormal pressure distribution in the collapsed arch area.
Test method
Static test: The subject stands barefoot on the pressure plate, and the system records the contact area, pressure peak and center of gravity distribution of the plantar. Flat feet are manifested as a significant increase in the contact area of the midfoot area and a lack of normal arch space.
Dynamic test: The subject walks or runs on the pressure plate, and analyzes parameters such as the plantar pressure transfer path, step length/step frequency symmetry during the gait cycle. Flat feet may be accompanied by gait imbalance caused by inversion or eversion of the foot.
II. Analysis of key biomechanical indicators
Arch Index (AI)
Calculation method: The ratio of the midfoot pressure area to the total plantar contact area. The AI value of flatfoot patients is higher than the normal range, reflecting the abnormal increase of midfoot pressure after arch collapse.
Pressure distribution heat map
The color gradient is used to display the intensity of plantar pressure. The forefoot and heel areas of the normal arch are high pressure (red/dark), and the midfoot is low pressure (blue/light); the midfoot area of flatfoot shows abnormal high pressure distribution.
Center of gravity trajectory (COP)
Evaluate the stability of plantar center of gravity movement during walking. Flatfoot patients often have center of gravity shift or increased swing amplitude, indicating gait compensation mechanism.
III. Functional verification and joint diagnosis
Quantitative evaluation
The system provides quantitative data such as plantar contact area ratio and pressure peak coordinates to avoid the subjective error of traditional visual inspection, especially suitable for early screening of children with flatfoot.
Three-dimensional data integration
Combined with the plantar three-dimensional scanner, the foot morphological data (such as arch height) can be obtained simultaneously to provide biomechanical support basis for customized orthotic insoles.
