Plantar Pressure Distribution System is a high-tech biomechanical device used to measure and analyze the force distribution across various regions of the sole during standing, walking, or physical activities. It is widely applied in fields such as rehabilitation medicine, sports science, footwear development, and athletic training.
Its core value lies in transforming invisible mechanical information into visual data charts, providing objective evidence for clinical diagnosis and functional assessment. To thoroughly understand its working principles, a systematic analysis of both hardware configuration and detection mechanisms is required.
- Hardware Configuration
A complete plantar pressure distribution system typically consists of three core hardware modules: the pressure sensing platform, the signal acquisition and processing unit, and the data analysis software.
Pressure Sensing Platform: This is the front-end sensing component of the system, directly bearing the pressure from the subject’s foot. Depending on the application scenario, it can be divided into two types: force plate type and insole-embedded type.
- Force Plate Type: Usually has a flat-panel structure, embedded with a high-density array of pressure sensors (such as capacitive, resistive, or piezoelectric sensors), commonly found in laboratories or rehabilitation centers. The platform surface is covered with wear-resistant material, and the sensors are arranged in a regular grid pattern, with density reaching multiple sensing points per square centimeter, ensuring high spatial resolution and measurement accuracy.
- Insole-Embedded Type: Flexible pressure sensors are integrated into shoe insoles, enabling wearable use, suitable for dynamic gait analysis or daily activity monitoring. These sensors often employ thin-film resistive or capacitive technologies, featuring lightweight, flexibility, and reusability.
Signal Acquisition and Processing Unit: Responsible for converting weak analog signals generated by the sensors into digital signals, and performing amplification, filtering, and preliminary processing. This unit typically includes an analog-to-digital converter (ADC), a microprocessor, and data transmission interfaces (such as USB, Bluetooth, or Wi-Fi), ensuring real-time and stable data transmission to computers or mobile devices. Sampling frequency generally ranges from 50Hz to 500Hz, meeting the requirements for both static and dynamic measurements.
Data Analysis Software: Serving as the “brain” of the system, the software receives raw data and uses algorithms to reconstruct visual outputs such as plantar pressure distribution heatmaps, center-of-pressure trajectory plots, and pressure-time curves. The software usually features region partitioning, peak pressure calculation, symmetry analysis, gait cycle identification, and supports data export and report generation.
- Detection Principles
The operation of the plantar pressure distribution system is based on the principle of “force-to-electrical signal conversion.” When the foot contacts the sensing platform, pressure acts on the sensor surface, causing internal physical changes (such as changes in resistance, compression of capacitor spacing, or deformation of piezoelectric materials), thereby generating an electrical signal proportional to the magnitude of the pressure. The system converts this electrical signal into actual pressure values (in units of kPa or N/cm²) using a calibration curve.
During data acquisition, the system continuously samples at a set frequency, forming time-series pressure data. Combined with the spatial coordinates of the sensors, the software generates 2D or 3D pressure distribution maps for each frame, dynamically displaying the evolution of plantar pressure over time. For example, in gait analysis, the pressure transfer path during heel strike, stance phase, and push-off can be clearly observed.
Additionally, the system is often combined with synchronized cameras or motion capture devices to enable “pressure-motion” synchronized analysis, further enhancing the comprehensiveness of the assessment.
