Quote Originally Posted by Redflad View Post
I've been using 60lbs, 7 reps and 2 sets once a week.

I've checked my form and my friend doesn't see anything wrong with it either. Guess it's better to replace them then but what's the best exercise for that?

Also, does anyone have any experience on swiss ball crunches?
I'd suggest dropping the weight a down to allow you to complete 2 sets of 15-20 with good form. Be sure to focus more on pulling with your abs, and try to leave your back/arms/hips/etc. out of the equation. There should be a very small range of motion in your movement, just like when you're doing a normal crunch. (I'm guessing that pulling with the hip flexors might be what's causing your back pains.)

As for swiss ball crunches, I don't know much about them to be honest. I guess they would offer a larger range of motion(Letting you lean back more.), so I assume that it would increase productivity much like standing on something to let your heels drop below parallel on calf raises.