The invention relates to a portable sports device and particularly a training device for muscle building, with at least one handle and a centrifugal mass operatively connected thereto and mounted on a shaft, which is rotatable by pulling a pull rope fixed to and wound up on the shaft, and with at least one removable additional mass element arrangeable on the centrifugal mass, the at least one additional mass element being configured in the form of a circular ring piece or a circular segment piece.