Abstract: A ball is provided for use in training that collapses when hit or kicked and then resiliently reforms itself to its original shape, dissipating kinetic energy and allowing use of the ball in a restricted geographical area. In one aspect, the ball of the invention includes incisions extending substantially through a shell, which deform upon striking, such that the ball and collapses venting air and dissipating kinetic energy. In another aspect, the ball of the present invention includes incisions extending only partially through the outer shell, contributing to the deforming properties of the ball when struck.