Abstract: An apparatus includes a harness attachable circumferentially around a waist area of an athlete. A mechanical resistance attachment guide is coupled to the harness and oriented circumferentially relative to the waist area of the athlete when the harness is worn by the athlete. The mechanical resistance attachment guide provides a circumferentially moveable approximately constant radius attachment location relative to an axis of rotation of the athlete throughout a rotational athletic swing. A vertical anchor plane is defined between the axis of rotation of the athlete and an anchor point located perpendicular to the axis of rotation of the athlete. At least a portion of the mechanical resistance attachment guide remains within the vertical anchor plane throughout the rotational athletic swing. This abstract is not to be considered limiting, since other embodiments may deviate from the features described in this abstract.