Quote:
Originally Posted by MikeB  You can do weighted crunches via either holding a dumbell or using a machine, weighted leg raises etc.
Here's a ton of ab exercises: Bodybuilding.com - Exercise Guides Database.
First you need to build enough strength to do basic crunches like the ultimate ab exercise link I gave you. You don't want to try any resistance style ab exercises until you you have prepared your muscles for that. Nothing worse than seriously sore abs... 
BTW, when I first started doing abs, I couldn't get past the first 2 sets of that ultimate ab workout without cramping badly. |
If she can do hundreds of crunches, she's ready for resistance.
That said, these should be the least of your worries at the moment. I haven't been following your programming..... but you should be focusing more on nutrition and directly speaking with regards to resistance training, you should be focusing on big, compound lifts.