Although power assisting devices were already considered promising for helping elderly and disabled person, we aim at expanding the application, such as muscle rehabilitation and sports training. The main focus of this research is to control the load of selected muscles using a power-assisting device, thus enabling pinpointed motion support, rehabilitation, and training. We also consider the device which has less DOF than number of joints. Although the simulation results verify the effectiveness of the proposed framework, we verify the effectiveness through the actual experiments.