It seems like the boat is lacking strength.

I went to the gym today. I usually have no trouble with basic ab exercises, but my lower back hurts like crazy whenever I lie down and extend my legs toward the ceiling, slowly lowering and raising them.

I was told not to lift my lower back, so I'm not being greedy and only lowering it very little by little, but I'm scared of injuring my back, so I can't exercise.

I'm getting back pain, not the muscle soreness that comes from enduring exercise.

Given my condition, is it correct to continue doing this abdominal exercise?