A power cage (also known as a power rack, squat cage or squat rack) is an item of weight training equipment designed to allow for a free-weight workout using a barbell without the movement restrictions imposed by equipment such as the Smith machine. It essentially comprises four vertical posts with two movable horizontal bar catchers on each side.
The power cage serves several purposes. It allows for a safe free-weight workout: if for example, in the bench press, a bar catcher is placed right above the athlete's chest, it becomes possible to load the barbell with the maximum weight, since the bar will prevent the barbell from crushing the chest in the case of a failure or accident. On the other hand, the power cage is often used for limited-range exercises, in which the athlete can handle far more weight than in their full-range equivalents. In the example of the bench press, if one of the bar catchers is placed just a few inches below the point where the barbell is lifted off, the result is a small space within which the athlete can perform unusually heavy lifts.
In this manner, an average lifter who can press a maximum of 225 lbs. will easily be able to advance to 250 lbs., thus getting the muscles accustomed to heavier weight. Power cages or racks have been known and used for a long time. They became popular in the 1960s, when Terry Todd and Dr. Craig Whitehead used them to test their "theory of maximum fatigue." Peary Rader then devoted a long article to the subject in his Iron Man magazine.[1] An updated version of the power cage was patented in 1987 by Karl I. Mullen of Portland, Oregon.[2]