In order to collect continuous and readily available human vibration energy, an electromagnetic energy-harvesting device embedded in a backpack is proposed based on the inerter component. The device also aims to enhance human comfort and overcome the challenge of damping matching in traditional energy harvesting devices. The energy transfer efficiency of the device was analysed using force-electricity analogy and the maximum power transfer theorem. The impact of the device on the load experienced by the human body was also taken into consideration by establishing mathematical models and researching human gait characteristics. The findings suggest that the device can enhance the efficiency of human vibration energy collection by introducing a new degree of freedom that enables effective adjustment of the system's natural frequency to match the human vibration frequency. Additionally, selecting appropriate inertance can significantly reduce the biomechanical load on the human body. Finally, the theoretical analysis was validated through a simulation platform based on the mechanism of human joint movement and a genetic algorithm, confirming the effectiveness of the proposed approach.