You can do this same exercise using a dumbbell between your feet. However, due to the angle of the pull of the cable this is actually slightly different and in my opinion harder. Keep the eccentric portion of the movement controlled as you lower your legs . Notice how I am not just lifting my legs up, but out and up by focusing on more of a reverse crunch form. The thought process should be tucking your lower abs into your upper abs while keeping the angle of your legs rigid as you come up. Once fatigue hits, form breaks down slightly and you can see it becomes a bit more of a leg raise. It’s important to understand the goal of an exercise and not simply go through the motions.