Pulse at the bottom and feel your quads scream.
Push your front knee out against the band so it never caves inward during the pulses.
Parking at the bottom of a lunge and pulsing keeps the quads under tension with no rest at either end of the range, while the band above your knees forces the glutes to hold the front knee out through every pulse. That combination of constant tension and abduction demand is why a bodyweight movement can leave your legs shaking. It slots in perfectly as a finisher after heavier leg work, or as the hard part of a home circuit when there's nothing to load.
Common schemes are 3 to 5 pulses per rep, or a straight 15 to 20 second pulse block per leg. Whatever you pick, the pulses should stay small, a few inches of travel at the bottom, not half reps.
The band is pulling it in and your glutes are losing the fight. Consciously press the knee out over your foot on every pulse, and if it still caves, move to a lighter band or fewer pulses until control returns.
Not better, different. Regular lunges let you move more load through full range, pulses maximise time under tension in the hardest position. Use regular lunges as your base and pulses to finish the job.
