A reformer exercise apparatus has a generally rectangular frame having a head end and a foot end and including a pair of spaced apart parallel track members, a movable carriage mounted on the frame for movement along the track members between said head and foot ends against one or more springs connected between the carriage and the foot end of the frame and an adjustable foot bar assembly mounted at the foot end of the frame. The foot bar assembly includes a foot bar and a foot bar support bar that fits into a pair of support brackets. Each bracket is a generally block shaped body fastened to the foot end of the frame. The bracket has a plurality of vertically spaced, downwardly opening slanted slots therein for receiving the support bar, each slanted slot having an entrance portion extending upward to an enlarged support portion at a base of the slot for retaining the support bar therein. The enlarged support portion forms a pocket to positively retain the support bar. A lock block that removably fastens to the foot bar support bar may be slidably inserted into the support portion of the bracket to lock the support bar in the support portion of the bracket.