Good cable ab exercises?

Anybody ever work their abs like this?

http://www.exrx.net/WeightExercises/...ingCrunch.html

or

http://www.exrx.net/WeightExercises/...tedCrunch.html

What results did you get from doing these kneeling and seated cable crunches?

I believe these work your upper AND lower abs.

Am I right?

Cable Crunches are good... when preformed correctely. Make sure you have strict form and don't push with your arms or sway at all Concentrate on isolating the abs and making sure you feel them burning.

Does this work upper AND lower abs?

Well the first one is actually incorrect a bit! Your glutes should not touch your heels. The second is really great & I do both all the time. Both exercises target the mid/upper abs ONLY.. Knee-ups, hanging leg raises or exercises that bring your lower torso into gut works the lower!!