Yongyue Song, Nan Zhang, Xiaoliang Li
Flexible sensors have attracted increasing attention in motion analysis and rehabilitation medicine owing to their lightweight design, stretchability, conformability, mechanical compliance, and excellent adaptability to human interfaces. This review focuses on the application of flexible sensors in biomechanical monitoring. It systematically summarizes the fundamental principles, detectable signal types, material systems, and structural design strategies of piezoresistive, capacitive, piezoelectric, triboelectric, and other emerging flexible sensors. In addition, methodological procedures for biomechanical signal acquisition, calibration, preprocessing, feature extraction, and intelligent modeling are discussed. In motion analysis, flexible sensors can be integrated into insoles, joint patches, garments, and sports equipment for gait analysis, plantar pressure monitoring, joint motion recognition, and sports performance assessment, with machine learning further enabling motion classification and movement-state identification. In rehabilitation medicine, flexible sensors can be used to monitor joint activity, human-machine interaction pressure, plantar loading, surface electromyography, force myography, and muscle fatigue during neurorehabilitation and muscle rehabilitation, thereby providing objective evidence for rehabilitation assessment, training feedback, and individualized intervention. Despite substantial progress, challenges remain in sensing accuracy and stability, long-term wearing reliability, inter-individual variability, multisensor fusion, data standardization, and clinical validation. In the future, the integration of flexible sensors with artificial intelligence, digital twins, bioelectronics, and self-healing materials is expected to promote the development of intelligent, continuous, and clinically translatable systems for sports health monitoring and precision rehabilitation.