A compressible barbell adapter is disclosed, which consists of a compression-retraction member fastened to a hollow shaft for use on a bar. The compression and retraction movement of the compression-retraction member is generally achieved by means of a pinion and a rack system, and can be utilized in conjunction with dampening means. Slidable handles are also connected to the compression-retraction member, and serve to slide along the axis of the hollow shaft, and thus along the bar. The compressible barbell adapter is meant to be fastened onto existing bars or barbells such that additional exertion is focused on the pectoral, deltoid and back muscles during various exercises.