Electrical stimulation is effective for various therapeutic applications; however, to increase convenience, it is crucial to eliminate generators and batteries for wireless power transmission. This paper presents a full textile-based body-coupled electrical stimulation (BCES) system designed for wireless electrical stimulation using energy loss from electronic devices and static electricity from physical activity. We developed the BCES socks by knitting conductive threads to ensure stability and comfort. BCES socks generate electric fields ranging from tens to hundreds of millivolts per millimeter, which are sufficient to activate muscle fibers. Experimental and computational analyses confirmed the effective concentration of the electric fields. Human trials demonstrated significant improvements in exercise performance, with a 21.47% increase in calf raise frequency, an 11.97% increase in repetition count, and a 6.25% reduction in muscle fatigue. These results indicate the potential of BCES socks as a practical battery-free solution for enhancing muscle activity and reducing fatigue.

Funding Information
* Korea Medical Device Development Fund grant funded by the Korean government (the Ministry of Science and ICT, the Ministry of Trade, Industry and Energy, the Ministry of Health and Welfare, and the Ministry of Food and Drug Safety) (RS-2022-00140621) (to G.L.)
* National Research Foundation of Korea (NRF) grant funded by the Korea government (MSIT) (No.2023R1A2C2006170) (to S.L.)
* NRF grant funded by the MSIT (RS-2024-00354178) (to J.H.).