Development of a training-oriented wearable knee joint exoskeleton for forming a scientific force application pattern in squat tasks

Background: Squat training enhances athletic performance but poses knee injury risks when the technique is poor. Objective: Develop a resistance-type wearable knee exoskeleton to cultivate a hip-dominant, knee-safe squat pattern. Methods: Fifteen healthy men performed squats with either the exoskeleton or with barbells at three matched loads. Three-dimensional motion, ground-reaction force, and electromyography data were processed in OpenSim and MATLAB to quantify joint kinematics, power share, and muscle contribution. Results: The exoskeleton significantly reduced average angular velocity at the hip, knee, and ankle (p < 0.05), increasing hip power contribution by 20%-40% while decreasing knee contribution by 20%-30%, confirming a hip-driven pattern. However, knee and ankle ranges of motion decreased by 7°-9°, and vastus medialis activation dropped by ∼50% (p < 0.05). Conclusion: The device effectively standardizes squat mechanics and off-loads the knee, yet individualized tuning and auxiliary mobility work are recommended to optimize training transfer and preserve functional range of motion.