Gait analysis devices themselves cannot directly detect knee loading, but they can estimate the loading of the knee joint during gait through indirect data. The detailed explanation is as follows:
1. Main functions of gait analysis devices:
Gait analysis devices generally include the following types of systems:
Pressure distribution systems (such as foot pressure plates and in-shoe pressure insoles)
They detect the pressure distribution on different areas of the foot while walking or standing.
They can reflect the left-right balance and dynamic changes in body loading during gait.
3D motion capture systems (such as optical motion capture with reflective markers)
They analyze the movement trajectory, angles, and velocities of lower limb joints (including the knee joint).
They infer the dynamic activity of the knee joint during walking.
Electromyography systems (EMG)
They detect the activation of muscles around the knee joint (e.g., quadriceps, hamstrings).
They indirectly reflect the muscle force related to knee joint loading and stabilization.
Force plates
They measure ground reaction forces, which can be used to estimate the total load borne by the lower limbs.
2. Can knee loading be detected?
It is not possible to directly measure the internal loading of the knee joint (such as joint contact forces).
However, it can be estimated by combining:
Ground reaction forces (from force plates),
Knee joint angles and gait cycle data (from motion capture),
Body weight,
Walking speed and gait cycle,
And then calculating knee joint loading (i.e., shear forces and axial loads) using biomechanical models.
3. Common analysis methods in clinical and research settings:
In clinical rehabilitation and orthopedic research, the following are commonly used:
Gait analysis systems combined with biomechanical modeling software (such as OpenSim),
To estimate knee joint loading, load duration, peak force, and related parameters.
