Abstract: A racket frame includes a face portion having an annular shape in planar view, a grip portion, and a shaft portion connecting the face portion and the grip portion. At least a part of the face portion, the grip portion, and the shaft portion includes a first tubular member. The first tubular member has an inner tubular part, an outer tubular part surrounding the inner tubular part, and a release layer sandwiched between the inner tubular part and the outer tubular part.

Abstract: A rubber foam for a shoe sole is composed of a rubber composition for foaming containing a rubber composition and a foaming agent, the rubber foam having (i) a loss factor tan ? (24° C.) at a frequency of 10 Hz and 24° C. that is 0.07 or less and (ii) an absolute value of a slope of a change in loss factor tan ? with temperature between a loss factor tan ? (?15° C.) at the frequency of 10 Hz and ?15° C. and the loss factor tan ? (24° C.) at the frequency of 10 Hz and 24° C., as calculated by the following equation, that is 0.002 or less: the absolute value of the slope of the change in tan ? with temperature=|[tan ? (?15° C.)?tan ? (24° C.)]/39|.