When doing a dead bug abdominal exercise with a stability ball, do you keep your lower back neutral or flat on the mat?
On back with a stability ball between your stacked knees over hips and hands pushing the ball into the knees. Extend opposite hand and leg and return to starting position. Is the back neutral or flat?Enter some more information that will help others answer your question
The only thing to avoid is an anterior pelvic tilt.
Hope this helps.
I personally don't know what dead bug means, but I can follow your description.
My belief has always been "neutral" but what does that mean today?
The main question would be: why? do you insist on either way?