I Have Back Pain. What Exercises Can I Do To Get Strengthen My Abs?

I went for physical therapy and the therapist recommended mostly exercises for strengthening my back via strengthening my abs. I am just starting to workout but I am making good progress in every thing except the way my abs look. They are firming up but I'm not losing any fat in the area. I need to work on my abs for my back, but also just because I REALLY need to trim my abs. My diet is not perfect but I rarely eat junk food, fried food, or any form of fast food. Like I said the rest of my body is coming together, but even when I was training consistently for years I always had trouble training my abs.
I figured it was your PT that advised you to strengthen your abdominals. That isn't bad advice, but very vague. Relying on crunches and sit-ups exlcusively is a bad idea. Not because they are bad for your back, but because ANY exercise used exclusively will cause overuse injuries.

You should also not fall into the current trap of using swiss balls, sit-fits, wobble boards, etc. as your main form of conditioning. I have unpleasantly seen a trend in conditioning where these tools become the main focus of training programs. While they may serve a purpose in very early forms of rehabilitation, they usually do not allow for one to gain great levels of strength and power. Yes, these qualities are important in improving your pain and giving you a better chance at not experiencing such a problem again.

Since it is impossible for me to evaluate you, I can only give you similar advice that I provided in the previous post. Make sure that you select ab exercises that do not hurt and that can help improve your range of motion in your spine. If you want some great ideas for movements like this I would recommend you check out Pavel Tsatouline's Beyond Crunches book and even his Russian Kettebell Challenge. Make sure that you are cleared to do any of the exercises included before you try them on your own. These techniques have greatly helped me with my back (having had two lower disc problems myself). You can get these at DragonDoor.com.

As far as actually "seeing" abdominal development, you must make sure your bodyfat is low enough. This is a combination of training and diet. Since you have been injured it would not surprise me that you would actually increase in bodyfat temporarily. Now that you are getting back into training make sure that you clean up the nutritional part and use some of the methods I have outlined in previous posts about losing bodyfat and increasing your work capacity.