"Yep, just like push-ups, there is a correct form for sit-ups.

Lie back with your knees bent at a 90 degree angle, with your feet together or up to 12 inches apart. Ideally, you would have another person hold your feet, but some other brace can work. Your ankles must stay in contact with the ground. Your hands should be behind your head, with your fingers interlocked. When you are in the down position, only your shoulder blades must touch the ground, your head/hands/elbows don't need to.

When you raise yourself to the up position, you must bring yourself to the vertical position. This means the base of your neck should be directly over the base of your spine. Then lower yourself back down so your shoulder blades touch the ground, that's 1. "

"I agree that the hands behind the head position is potentially dangerous. The Air Force standard is fingertips must stay in contact with the collarbone, but that seems to result in people only coming up to touch their elbows to their knees.

As long as you are aware of the hazard, you can be mindful not to pull on your head, only use your abs.

But yes, the Army needs an update."