The World Textile Information Network predicts that the sports and fitness smart textile market will reach US$2.85 billion by 2026. The increase in demand for fitness-related products in the post-pandemic era will also drive the growth of the home exercise and fitness market. Therefore, the Taiwan Textile Research Institute integrated wearable inertial sensors and textile electromyography electrodes to develop a two-in-one precision sports auxiliary clothing system, which can continuously monitor changes in a user’s joint angle and muscle activity status in real time and achieve precision motion assistance using a graphical brain–machine interface.