Soft wearable exosuits represent a promising technology for biomechanical augmentation and rehabilitation. Offering a lightweight, garment-like alternative to historical rigid exoskeletons, they significantly improve user comfort and transparency. However, their compliant structure, typically relying on textiles and elastomer straps, introduces critical challenges in force transmission. These issues become particularly evident when delivering high torques for hip extension during the stance phase, where the lack of a rigid skeletal frame can cause anchoring slippage, altering assistance profiles and potentially causing user discomfort. In this context, musculoskeletal simulations have emerged as an invaluable tool to investigate complex human-robot interactions (HRI), providing predictive design insights that would otherwise require extensive, invasive, and time-consuming experimental protocols.