Non-invasive wearable devices can continuously monitor physiological status including muscle activity for healthcare, sports, and various applications. Wearable electromyography (EMG) systems rely on interconnects to link surface EMG (sEMG) sensors with the associated circuitry in textile-based systems. Rivet-embedded interconnects present a promising solution, offering stable mechanical and electrical contact while maintaining comfort and wearability. However, the performance of these interconnects can be influenced by the structure of the textile substrate. This study evaluates the impact of three different knit textile structures—single jersey, interlock, and spacer knit—on the performance of rivet-based interconnects in wearable EMG armbands. The armbands were subjected to a domestic washing cycle, and the resistance measurements and EMG signal were monitored before and after washing. The primary objective of this work was to assess the effect of washing on the rivet-embedded interconnects using the three textile substrates. The results demonstrate that interlock fabric maintained stable EMG signal performance post-washing, with no significant resistance change in the interconnect. In contrast, single jersey and spacer fabrics exhibited significant degradation in EMG signal quality and resistance after washing. These findings suggest that interlock fabric is the most suitable choice for embedding rivet-based interconnects in wearable EMG armbands, ensuring both durability and functionality in real-world conditions. This study highlights the importance of textile structure for integration of electronic components and ensuring the overall functionality of textile-based wearable devices. Understanding these relationships is essential for advancing next-generation e-textile technologies.