Workout equipment that detects and adjusts the effective weight automatically, within individual repetitions and between sets. The equipment is able to vary the exercise resistance during the stroke to allow the user to push through a weak spot and gain the maximum benefit of exercising to their full range of motion. The equipment detects weakness preceding muscle failure by the speed at which the user is manipulating the device. Users are instructed to complete each repetition slowly, smoothly and to their fullest extension or flexion and to return to the starting position slowly and under control at all times. The equipment can detect when a user is slowing down and straining at a given level of resistance, or at a particular point in the stroke path, and it will automatically lessen the effective weight to allow the user to push through and complete the stroke. The overall effect of this is to spot the user in the same manner that a personal trainer would provide assistance at the critical point in the exercise stroke. This allows the user to safely workout with heavier weights than they would be able to do alone. An additional feature of the machine is personalized monitoring. A computer added to the equipment can adjust the weight between repetitions to, for example, provide the user with the ability to "stack" at incremental weights. The computer is programmed with the user's personal fitness goals which determine the "success criterion" for the workout. When a user achieves their success criterion, the machine "counts" those repetitions towards the overall fitness goals and adjusts the effective weight between repetitions, and between workout sessions. This exercise equipment allows an individual to increase his or her level of fitness rapidly, safely, with minimal fitness plateaus and without the need for a personal trainer to spot them.