decline crunch

I get lower back pain in the bottom of the movement when I try these, so I do them with legs extended with feet hooked on the leg curl pads instead. Does this screw up the dynamics of the crunch? Is there anything else I should try?

It doesn’t mess with the dynamics if you have the technique down. Remember with any crunch you need to follow simple rules. Watch this video here as I review. http://www.workouttrainer.com/home/videos/workout-0abdominal-essentials