Set up with ropes around an anchor. Sit into a partial squat, using some of the tension of the ropes to sit more upright than a usual squat. You can do alternating ropes (first part of the video) or slams (second part of the video), or switch back and forth between the two. Usually these are done for time. Try to feel the work through the front of your core, staying low with a neutral spine especially through your low back.