An exercise apparatus for isolating and strengthening upper back and shoulder muscles including opposed first and second outboard support members containing separate and opposed sets of stacked weights supported for reciprocation vertically, and an upper cross-member containing a pair of aligned upper roller tracks. The frame includes a pair of inboard first and second crossbars supported at opposed ends in upper and lower roller tracks of the frame, such that the crossbars are manipulated in opposed outwardly directions by the user positioned therebetween. Separate cables and supporting pulleys are utilized to extend between first and second crossbars for connections to respective opposed sets of stacked weights, allowing for concurrent movement of weights when each crossbar is moved laterally outwardly and inwardly by user's right and left hands in palm-out orientation, thereby isolating and strengthening the user's upper back and shoulder muscles.