A golf muscle weight training apparatus for attachment to the shaft of a golf club or other sports implement includes a weight carrier having an elongated weight supporting portion, a weight, and a clamp mechanism. Materials other than SiC may be used as the substrate material. A high frequency electric power introduced into the cavity resonator is resonated in the parallel direction to the side wall surfaces on an excited mode with a constant electric field intensity along the side wall surfaces. The comparator is connected to the voltage converting circuit and outputs a PWM voltage to the voltage converting circuit. The conductive metal oxide portion serves to promote the growth of the high k phase of the dielectric layer.