The degree to which hamstrings and quads work during a lunge depends on the variation and length of your step. The forward lunge is knee-dominant, meaning the quads work slightly more than the hamstrings. The reverse lunge is hip-dominant, focusing more on the glutes and hamstrings. With most lunge variations, taking a small step forward or back activates the quads more, and a larger step activates the hips and hamstrings more.