Select a cable height so that when you're kneeling you can just reach the rope grip. Grab the rope grip with your hands facing inwards and position them beside your neck.

Crunch down leading your chin towards your knees, go as far as possible without hitting the ground, then slowly return upwards until your torso is straightened. Maintain a consistent elbow bend throughout to isolate your core. Conduct the movement at a controlled pace. Repeat for the desired amount of repetitions.

Avoid extending the elbows to help pull the weight or using excessive momentum.