During the curl-up exercise, maintaining a neutral head position with the chin off the chest and the tongue on the roof of the mouth facilitates proper form, breathing, and a safe default head posture.

“the head is in a neutral position okay so your chin isn't tucked toward your chest the chin is in a neutral position and this is important your tongue is on the roof of your mouth this is something I talked a little bit about in my description of neck exercises in a previous video we're going to get back to this but tongue on the roof of the mouth often puts the head into a safe default position it also allows for breathing in particular nasal breathing to be done very easily”