Are declined sit ups bad?

[musclemom]

I've got a screwed up back. Sit-ups and crunches are difficult, and I know I'm using my hip adductors to complete the movement. To add to Bunny's suggestions I find these isolate my abdominal muscles without back injury:

http://www.exrx.net/WeightExercises/RectusAbdominis/WtHangingLegHipRaise.html

I won't lie, I can't do them with weight, and I can't get my knees that high ...

 

[BeeFeaTeR93]

bump on the Yoga balls...you get more than full range of motion to target all the abs.

 

[DZLS]

how come training questions keep popping up in this forum...?