Cross behind and sink low. Glutes get hit from a new angle.
Keep your front knee tracking over your foot and your chest tall as you sink.
Crossing one leg behind and across the other drops your hips into a diagonal line as you lower, which puts the glute of the front leg, especially the outer portion, under a stretch a straight lunge never finds. The quads help control the knee bend, and the ball held at your chest adds load while doubling as a counterbalance for the awkward angle. It earns its slot when your lunges are strong but your hips still wobble side to side.
The diagonal step behind loads the glutes from a different angle, biasing the outer hip and challenging side-to-side stability. Regular lunges build the engine, curtsy lunges build the steering.
Far enough that you feel the front-leg glute stretch as you sink, not so far that your hips twist open or your front knee dives inward. Start conservative, a modest cross with control beats a deep one with wobble.
Yes, it is load and balance in one. Held tight to your chest, the ball keeps your torso tall and your weight centred over the front foot. Let it drift forward and it drags your chest down, which tips the whole rep.
