How the plantar pressure plate measures flat feet

The principle of using a pressure plate to evaluate flat feet is mainly based on the analysis of plantar pressure distribution, arch load and center of gravity trajectory. The specific working principle is as follows:

Static measurement (standing state)

The subject stands on the pressure plate, and the system collects the pressure distribution of each area of the sole. In the case of a normal arch, the plantar pressure is mainly distributed in the heel and forefoot, and the pressure in the arch area is relatively low. If the arch collapses (flat feet), the pressure in the medial arch area will increase significantly, even close to the pressure value of the forefoot and heel.

Dynamic measurement (walking or running state)

The subject walks on the pressure plate, and the system analyzes the pressure changes on the sole during gait. The gait of a normal arch is characterized by heel landing → lateral transition → forefoot pushing off the ground, while flat feet are characterized by increased load on the inner side of the sole, which may cause inversion (excessive internal rotation) of the foot, leading to abnormal gait.

Plant pressure distribution map

The plantar pressure heat map can intuitively show the force on the sole. The arch area of a normal foot usually shows low or no pressure, while the arch area of a flat foot shows high pressure, which appears as a dark area.

Center of Pressure Track (COP Track)

The COP (center of gravity track) is an important indicator of gait balance. In a normal gait, the center of gravity track moves along the outside of the foot, while the COP track of a flat foot may be biased towards the inside of the foot, indicating poor gait stability.

Arch Index Calculation

The plantar pressure system can calculate the Arch Index (AI), which is the ratio of the arch area to the entire plantar force area. Generally, a high arch index may indicate flat feet, while a low arch index may indicate a high arch.

Through these measurements, the plantar pressure plate can accurately assess the degree of arch collapse, helping doctors, rehabilitators or sports scientists develop targeted intervention plans, such as corrective insoles, gait training or rehabilitation therapy.