Abstract: A hand development apparatus is provided with a first housing having an interior cavity formed therein and a gripping portion adapted to fit the palm of a person's hand and a second housing having an interior cavity formed therein and a gripping portion adapted to fit the palm of a person's hand. The apparatus has a carrier adapted to be removably fitted within the interior cavity of the first housing or within the interior cavity of the second housing, a plurality of movable elements associated with the carrier, the movable elements being adapted to accommodate the fingers of a person's hand and being movable along a movement direction, and springs for resisting movement of the movable elements along the movement direction. The width of the first housing is substantially different than the width of the second housing so that the apparatus may be configured either for a person having relatively large hands or a person having relatively small hands.

Abstract: A hand development system to increase the strength and flexibility of the hands, fingers and forearms of a user. It includes a body adapted to be gripped by the hand of the user and a plurality of individually movable members operatively associated with the body. Each of the individually movable members, which may be in the form of keys, is adapted to be moved by one of the fingers of the user against resistance to movement provided by a component such as a spring. It includes a set of replaceable cartridges disposed in an interior compartment of the body for this purpose. With this construction, the cartridges each include at least one spring having a selected resistance to movement and each of the cartridges is positioned to resist movement of one of the keys.