NOVELTY - A computer program is executable by a controller to generate a position-varying target force band for a user over a range of motion. The controller is in communication with a motor, a force sensor, and at least one position sensor. A display in communication with the controller and force and position sensors exhibits user-applied force as a function of position in real time in comparison with the target force band.    USE - Strength training system for use by e.g. elderly, world-class athletes, exercise intolerant individuals, rehabilitation patients.    ADVANTAGE - Utilizes computer-controlled motor drive and real-time graphical force feedback display to guide users through advanced training protocols that cannot be performed with traditional equipment. Customized protocols promote greater increases in strength and evoke response within muscle that provides improved protection from injury. Easy to use and sufficiently versatile to benefit everyone from frail elderly to world-class athletes. Provides variable resistance capability that meets needs of high end athletes and which can be customized to enable exercise intolerant individuals, elderly and rehabilitation patients to increase their strength while experiencing minimal cardiovascular stress. Training partner is not required to use strength training system. Provides balanced workout by challenging muscles in both velocity-controlled shortening and lengthening contraction phases of movement in manner that can be tailored to individual user. Minimizes patellofemoral joint compression during training and potential aggravation of patellofemoral pathologies by reducing target resistance levels at deep knee flexion angles. Velocity-controlled variable resistance protocols enable users to load their muscles more optimally along entire range of motion in either or both velocity-controlled shortening and lengthening phases of training repetition to stimulate greater muscle hypertrophy. Suitable for either time-compacted, high intensity training or endurance style training at low intensity. Teaches force steadiness and control.    DETAILED DESCRIPTION - A user support portion for supporting a user is coupled to a frame. The force sensor detects user-applied force at a user engagement portion that is coupled to the frame and is configured to be engaged by at least one body part of the user. The position sensor is connected to at least one of the user support portion and user engagement portion and detects relative position between the user support portion and user engagement portion. The motor drives the user support portion and user engagement portion with respect to the frame over the range of motion at a preprogrammed velocity.    DESCRIPTION OF DRAWING(S) - The drawing shows a chart of the force-velocity relationship of skeletal muscle.