Self-powered triboelectric sensing system for gait-based physiological and psychological assessment in track and field

Wearable sensors have become essential components in smart sports systems for real-time monitoring of athletic performance, physiological conditions, and psychological states. In this work, a sodium alginate/gelatin-based triboelectric nanogenerator (SG-TENG) was developed for mechanical energy harvesting and real-time monitoring in track and field applications. The SA/gelatin composite film exhibits excellent transparency, flexibility, and homogeneous morphology, enabling stable triboelectric performance. The SG-TENG delivers a high output with a peak open-circuit voltage (VOC) of 156.6 V, short-circuit current (ISC) of 46.9 μA, and transferred charge (QSC) of 139.6 nC, achieving a maximum power of 13.5 mW under optimal load. Its output performance is strongly dependent on mechanical parameters such as frequency, force, displacement, and contact area. In addition, the device shows effective energy storage capability by charging capacitors under various conditions. Integrated into a running shoe, the SG-TENG enables self-powered gait monitoring and accurately distinguishes physical activities including walking, running, and jumping. Furthermore, it demonstrates the ability to infer psychological and physiological states from gait dynamics, highlighting its potential for battery-free, multifunctional sensing in sports performance and health monitoring.