A modular support assembly for hanging exercising and training apparatus includes a pair of vertical elements and a horizontal element. The horizontal element is configured to selectively engage upper ends of the vertical elements so that the two vertical elements extend perpendicularly and codirectionally from opposed ends of the horizontal element to a surface. Exercising or training apparatus can be hung from the horizontal element. The vertical elements are two of a plurality of vertical elements and the horizontal element is one of a plurality of horizontal elements. Each vertical element can selectively engage respective opposed ends of two horizontal elements so that the two horizontal elements extend perpendicularly from the upper end of the vertical element. The set of horizontal elements and the set of vertical elements thus are selectively positionable in a variety of rectangular configurations.