An assembly for use with a weight rack includes a mounting rail for mounting to the weight rack, including a plurality of rail sections extending laterally and spaced along the length of the mounting rail to define slots therebetween. The accessory includes a mounting portion for removably mounting to the mounting rail and a functional portion connected to the mounting portion for use in a weightlifting exercise. The mounting portion includes a fixed portion and a moveable portion that is moveable with respect to the fixed portion between a locked position, where the fixed portion and the moveable portion engage the mounting rail, and a release position, where the accessory can be removed from the rail. The mounting portion also includes a peg received in one of the slots of the mounting rail and a locking mechanism that moves the moveable portion between the locked position and the release position.