The importance of regular exercise for building and maintaining strength and endurance cannot be overemphasized. The modern conveniences which we enjoy and the sedentary tasks which we increasingly perform have given us a comfortable lifestyle at the expense of physical fitness. Highly active exercise programs, such as running, develop endurance of the cardiovascular system. Muscular strength and endurance is best developed through weight training.
The simplest and least expensive apparatus for weight training is the barbell with removable weights. However, the use of a barbell alone cannot develop all areas of the body. Hence, additional apparatus must be employed for a comprehensive conditioning program. Devices developed for this purpose generally provide the user with a force resister against which muscular effort must be applied. Resistance is typically provided by means of a weight and pulley arrangement, or an elastic element. These devices permit the force to be applied to the user's body from many different directions in order to develop substantially all areas of the body.
Few of these weight training devices, however can provide the user with substantially all of the exercising variants required to develop the entire body. Those that do are generally large, complex and costly machines which occupy a substantial amount of space, cannot be used with a common barbell set and consequently are not suitable for home use. These are usually found only at health clubs and other athletic establishments. More specialized devices for developing limited areas of the body are available, but a number of different devices of this type must be used in order to provide a complete range of exercises.