To enable a user to strength his/her gripping power, ensure stability of swing, and improve head and speed and simply by perform swing exercise with the subject sheet loosely wound around a grip of a golf club by forming the sheet of an elastic sheet having a specified thickness, tensile strength, tensile elongation, and tearing resistance.

This sheet 1 is formed of a sheet 1 that has a thickness of 1-4 mm, preferably 1.5-3 mm and a proper elasticity, and thereby it can be easily wound around a grip 6 of a golf club 5 or a racket and has a required thickness and elasticity (repelling force) easily by changing the winding times as wall as can control the burden applied to fingers and hands. Since it has a proper elasticity of such as a tensile strength of 18-80 N/cm2, a tensile elongation of 60-150%, a tearing strength of 8-30 N/cm2, a proper load is given to fingers and hands. Accordingly, it is possible to improve the gripping power of both hands naturally only by performing a normal swing exercise with the sheet loosely wound around the grip 6.