Gait analysis is a technology used to evaluate the way a person walks. It analyzes the biomechanical characteristics of walking by measuring kinematics, kinetics, and electromyographic activity (EMG) during the gait cycle. Gait analysis equipment is widely used in sports medicine, rehabilitation therapy, podiatry, orthotics and prosthesis evaluation, and other fields. Its working principle is based on a variety of sensor technologies, computer algorithms, and biomechanical models to accurately capture human gait parameters.
In order to scientifically and rigorously understand the functions and operating mechanisms of gait analysis equipment, it is necessary to conduct a detailed analysis from the two aspects of its components and core working principles.
Gait analysis equipment usually consists of the following key parts:
First, the motion capture system. This system is used to record the trajectory of human motion, mainly including an optical motion capture system, an inertial measurement unit (IMU), and a depth camera. The optical motion capture system uses infrared cameras and reflective markers to track three-dimensional motion trajectories, such as Vicon, Qualisys, and other systems. Inertial measurement units include accelerometers, gyroscopes, and magnetometers, which are used to record human motion in real time, such as systems such as Xsens and Noraxon. Depth cameras (such as Microsoft Kinect) can capture human gait data without markers, although the accuracy is slightly lower. The main function of the motion capture system is to record the motion trajectory of each joint of the lower limb (hip, knee, ankle) to analyze gait kinematic parameters, such as step length, step speed, joint angle changes, etc.
Second, the plantar pressure distribution system (Plantar Pressure System). This system is used to measure the force on the sole of the foot during walking, mainly including the pressure measurement gait plate (Gait Analysis Plate) and smart insoles (In-Shoe Pressure Sensors). The pressure measurement gait plate is embedded with high-precision sensors (such as piezoelectric, capacitive or strain gauge sensors) to record plantar pressure distribution data in real time. Smart insoles (such as F-Scan, RSscan and other systems) embed flexible pressure sensors into shoes to provide dynamic gait data. The system can evaluate gait stability, load symmetry, and abnormal plantar pressure distribution (such as metatarsalgia and diabetic foot).
Third, the ground reaction force measurement system (Force Plate System). This system is used to record the force between the foot and the ground during walking, and mainly includes force plates (Force Plate), such as AMTI, Kistler and other equipment. Force plates usually have built-in piezoelectric or strain gauge sensors, which can measure three-dimensional force components (vertical, front and back, left and right directions) and calculate ground reaction forces (GRF). Combined with the motion capture system, the force plate can further calculate joint torque, power and energy consumption, which is used to evaluate gait abnormalities, sports injury risks, etc.
Fourth, the electromyographic signal acquisition system (EMG System). This system is used to measure the electrical activity of lower limb muscles during gait to evaluate muscle activation patterns. It mainly uses surface electromyography (sEMG) or needle electrode electromyography (iEMG) for signal acquisition, such as Delsys, Noraxon and other equipment. Combining kinematic and kinetic data, the system can analyze muscle coordination, fatigue level, and abnormal muscle activity patterns during gait (such as the gait of hemiplegic patients).
Fifth, data processing and analysis software. The collected data needs to be processed by dedicated computer software (such as Vicon Nexus, Qualisys Track Manager). Combining biomechanical modeling and artificial intelligence algorithms, the software can automatically calculate gait parameters such as step length, step speed, symmetry, swing phase/support phase ratio, gait energy consumption, etc.
The operation of gait analysis equipment involves three key steps: data collection, processing, and result analysis.
The first is data collection. The motion capture system records the movement trajectory of the lower limbs through a camera or inertial sensor and calculates the angle changes of the hip, knee, and ankle joints. The plantar pressure system measures the force in different areas of the foot and draws a plantar pressure distribution map. The force plate records the ground reaction force and calculates the mechanical characteristics during gait. The electromyographic system records the activation of the main muscle groups during gait to evaluate neuromuscular function.
The second is data processing. Motion data usually needs to be transformed and filtered (such as Butterworth filtering) to remove noise. Mechanical data is analyzed by inverse dynamics to calculate key parameters such as joint torque and power. Combined with gait phase segmentation algorithm (such as Heel Strike Detection), the complete gait cycle is analyzed.
Finally, the result analysis is performed. This stage calculates gait spatiotemporal parameters (step length, step speed, step frequency, gait cycle, etc.), analyzes joint kinematic parameters (such as knee flexion and extension angle, ankle dorsiflexion/plantar flexion angle), evaluates gait dynamic parameters (such as ground reaction force, plantar pressure distribution), and combines electromyographic data to determine whether there is an abnormality in gait (such as gait asymmetry, abnormal muscle activity pattern, etc.).
Gait analysis equipment is widely used in medical, sports science, rehabilitation engineering, and robotic walking assistance. For example, in the assessment of sports injuries, the device can be used to determine whether the athlete’s gait is abnormal to predict the risk of injury. In the field of rehabilitation therapy, it can help stroke and hemiplegia patients restore normal gait. During the orthosis and prosthesis optimization process, the device can analyze the patient’s gait, optimize the prosthesis design, and improve walking stability. In addition, the field of smart shoe design can also use gait data to provide a scientific basis for personalized footwear products.
Gait analysis equipment comprehensively evaluates human walking patterns through a variety of technologies such as motion capture systems, plantar pressure measurement, ground reaction force testing, and electromyographic signal acquisition. Its core working principle is to combine biomechanical modeling and data analysis to analyze the spatiotemporal, kinematic, and dynamic characteristics of gait in order to detect gait abnormalities, optimize athletic performance, or provide rehabilitation guidance. With the development of artificial intelligence and big data analysis, gait analysis equipment will play a more important role in precision medicine, sports science, and smart wearables.
