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.

Abstract: Martial arts striking apparatus including a striking board and mounting apparatus for mounting the striking board at different vertical heights and at different angles with respect to the vertical and for mounting the striking board resiliently whereby the board will pivot in response to a received blow and will thereafter be returned to its initial position.