Hydrogels possess significant potential for the development of multifunctional soft materials in smart sensors and wearable devices, attributed to their distinctive properties of softness, conductivity, and biocompatibility. Nevertheless, their widespread application is frequently limited by inadequate mechanical strength and strain capacity. This study introduces a meticulously engineered hydrogel system, LM/SA/P(AAM-co-BMA), which integrates eutectic gallium-indium alloy (EGaIn) as both a polymerization initiator and a flexible filler. The resultant hydrogel demonstrates remarkable tensile strain capabilities of up to 2800% and a tensile strength of 2.3 MPa, achieved through a synergistic interplay of ionic coordination, hydrogen bonding, and physical polymer interactions. Furthermore, the hydrogel exhibits outstanding biocompatibility, recyclability, and stable long-term storage, rendering it an ideal candidate for the continuous monitoring of high-intensity physical activities.