Cross Body Mountain Climber

The cross body mountain climber drives each knee toward the opposite elbow rather than straight forward, and that diagonal path is what separates it from the standard version. Crossing the midline requires rotation from the trunk, so the obliques produce the movement while the rest of the core holds the plank against gravity. You get conditioning and rotational core work in the same exercise, with no equipment and very little space. The pace decides which one you emphasise: slow and deliberate makes it a core exercise, fast makes it a conditioning drill, and both are legitimate. What ruins it either way is the hips rising. As the knee travels across, it is tempting to pike upward to make room, which releases the tension the plank was creating and turns the movement into a shuffle.