The present disclosure relates to a body-building power generation apparatus and a method of generating power using the power generation apparatus, comprising at least one fitness device, an energy storage device connected with the fitness device for transforming and storing the kinetic energy transmitted from the fitness device, wherein the energy stored in the energy storage device can be transformed into kinetic energy and outputted by an output mechanism connected with the energy storage device, a speed changing mechanism, receiving the kinetic energy from the output mechanism and outputting said kinetic energy after adjusting it, and a generator connected to the speed changing mechanism for transforming the adjusted kinetic energy into electric energy. The body-building power generation apparatus according to the present disclosure can satisfy or at least partially supplement the need of electricity in residential areas, office buildings, or leisure facilities; it can also act as backup power source to alleviate piezoelectricity or power failure in rush hours.