Abstract: This invention provides an inexpensive athletic exercising system for development of muscles of the athlete to increase the velocity and strength of movement of a body member away from an initial position toward a further position employing in a preferred embodiment of the invention a set of two magnetic members for magnetic retention together with a predetermined magnetic force. The first magnetic member is affixed to an athletic vehicle, such as a tennis racquet, ball bat or hockey stick, to be manipulated by said athlete. The second magnetic member is positioned at a restrained position from which an athletic stroke is initiated for magnetic retention together with the first magnetic member. This system permits an athlete to develop strength and speed in muscular reaction over an athletic stroke by manual manipulation of the athletic vehicle to overcome the predetermined magnetic force while permitting a substantially unimpeded follow through stroke after the initial magnetic force is overcome.

Abstract: It is critical to prevent muscular damage to an athlete in a machine that produces a restraining force that must be overcome in the initial part of an exercise stroke. This is achieved by a precise and accurate type of control system by which the athlete safely and surely control the initial restraining force magnitude. With a reliable vernier type control device the athlete then may "inch-by-inch" increase the restraining force as the muscles become able to overcome greater forces in the manner the proverbial strong man lifts a calf each day so that he can lift a full grown cow eventually. In a preferred embodiment of this vernier type control the restraining device comprises an electromagnet with a retained magnetic member coupled to the athlete by an intermediate muscular operated linkage.

Abstract: Muscular development of an athlete is achieved for increasing the starting acceleration and stroke speed when an athlete initiates a movement stroke such as a punch from a boxer's arm, throwing a baseball pitch or kicking a football, etc. by the means and method of this invention. Thus, the initial movement of the athlete is restrained with an external force of predetermined magnitude which is released in response to the athlete's movement overcoming the restraining force. Thus, those muscles are developed which are used in initiating motion so that they deliver greater initial acceleration to attain higher stroking speed which is converted to an impact blow of greater force. An exercise machine for such muscular training provides the initial but releasable restraining force by means of two separable magnetically attracted members having the predetermined initial force adjustably varied by introducing a variable air gap distance between the magnetically attracted members.