:: Pre-Exhaustion ::

The Pre-Exhaustion Principle employs what has been called a "double set": one single-joint movement followed quickly by a multi-joint movement.
The single-joint movement that is best for isolating the "quads" is the Leg Extensions. The Leg Press can be used as a secondary movement. In this case, the glutes and hamstrings are used to exercise the pre-fatigued quadriceps.