Various types of exercise equipment have been developed throughout history. This equipment is often directed to the exercising and strengthening of various muscle groups, such as the commonly known hand-held squeezing devices for exercising muscles of the hands and lower arms. However, more complex devices have been designed for use in strengthening and exercising other selected muscle groups. Historically, many of these devices used weights, springs or other preset resistances to movement. Such devices required the user to use only that amount of strength necessary to move the device through a weakest part of any movement.
Recently, other devices have been developed which offer resistance at a level adapting automatically to the user's abilities and providing resistance at a level the same or nearly the same as the force applied throughout the entire range of an exercise stroke. Such equipment is typically referred to as "isokinetic" exercising equipment. Many isokinetic exercise devices are relatively complex, expensive and require frequent maintenance. In addition, many of these devices are relatively large and typically require positioning at a stationary fixed location.
Examples of isokinetic exercising equipment are disclosed in the Mattox, U.S. Pat. Nos. 4,249,725 issued Feb. 10, 1981, and 4,385,760 issued May 31, 1983. More recently, a new isokinetic exercise device has the form of a cane which is relatively portable and capable of movement from location to location. This device is particularly advantageous for handicapped individuals.
Although the cane provides substantial advantages over other known exercising equipment, the number and variety of different exercises that can be performed for muscle/skeletal groups in a particular body region is somewhat limited. For example, the variety of exercises available for muscle/skeletal groups in the shoulder region is limited when the user must grip the exercising apparatus with both hands, or when the apparatus does not provide any supporting structure for the user's arm region so as to gain leverage.
One type of known exercise apparatus at least partially overcoming these disadavntages and specifically directed to exercises for shoulder and wrist muscle/skeletal groups employs a bell crank coupled to a sleeve-like slide. The slide is friction mounted to a horizontal stationary tube connected to opposing ends of a supporting structure. Rotation of the bell crank by the user is opposed in an isokinetic manner by the resistance to movement of the slide in an axial direction with respect to the tube.
It is also advantageous in exercising equipment to employ mechanisms for measuring forces exerted by the user during exercise. For example, in the Varney et al U.S. Pat. No. 3,971,255 issued July 27, 1976, an exercise bar includes a sleeve mounted to an elongated tube and slidable with respect to the tube. Bushings within the tube provide a friction slide between the sleeve and the tube, and handles are provided on the sleeve and at one end of the tube. Resistance of the sleeve on the tube is provided through a flat-headed pin and adjustably tensioned spring which exerts forces on the pin. A force measuring device is provided by a coil spring which is positioned between the outer end of the sleeve and an internal bushing. A gauge is mounted on the sleeve and indicates the amount of force applied by the user.