The principle of the back exerciser is a pedal held in an initial position by elastic strips and a back brace and side handles in such relation that the person pressing on the side handles and bracing his back against the back brace, repeatedly pressing his heels on the pedal against the action of the elastic strips, exercises his back muscles. The structure is a skeleton frame with a pivoted pedal having its rear edge raised by elastic strips toward a back frame so that the elastic strips pull the back edge of the pedal upward and the front edge downward against a stop holding the pedal in a horizontal position. On the back frame at a suitable height is a padded back brace for the person to bear against when he presses the pedal down against the action of the elastic strips.

An apparatus for assisting in performing pull-ups under an overhead bar (B) provides an adjustable upward force on a foot holder (2) to decrease the effort needed for pulling up the body. The force is adjusted by varying the number of bungee-cord linear springs (3) between the bar and the foot holder. The holder has a platform (22) and a shoe strap (11) to hold just one of the user's feet; the other foot is wrapped around the other leg. Looped ends of the bungee cords, formed by clamps (4), are attached with rings (14) or carabiners (6) to the platform and to straps (7) looped around the bar. A safety strap (1) holds the foot holder stable.

A multipurpose exercise machine for fitness and strength training at home is convertible for various exercises. The exercise machine is compact, light in weight, and includes a frame, a shaft, an eccentric wheel, a displaceable traveler, a pulling element, at least one exercise lever, and an optional coupling element for adding additional parts.

An exercise machine for assisting a user in performing chin-ups and dips includes a pair of handles attached to a frame and a kneeling platform operably connected to the frame by a four-bar linkage. The pair of handles may be a pair of chin-up handles attached to an upper portion of the frame or a pair of dip handles attached to a medial portion of the frame. The four-bar linkage moves the kneeling platform along an arcuate path of travel corresponding to the natural arcuate path of the center of gravity of the user during a chin-up or a dip so that the kneeling platform remains beneath the user's center of gravity during performance of a chin-up or a dip. The four-bar linkage also preferably maintains the kneeling platform in a horizontal orientation. A selectable number of weights urge the kneeling platform upward so that the user may lift his body with his arms while applying a force less than his own body weight.

A therapeutic device comprising a base, usually resting upon a floor, and a platform, usually located above the base that is maintained rigidly parallel to the base in a horizontal plane throughout up and down cycles. The platform is attached either with (a) pivotally attached arm(s) or by (b) freely operating sleeve(s) on to one or more vertical extensions or rigid attachments to/of the base. The platform, upon which the user is located, is moved up and down in a cycle initiated and maintained by the sustained activity of a spring suspension, or by, or in combination with, a motor driven reciprocal drive. This up and down cycle of accelerating and decelerating in line with extant gravitational pull occurs resultant strengthening of the body cells and organs, and stimulates circulation and body functions for the occupant user.