Exercise videos showing how to perform a Crunch.
The Curl-Up, or Crunch, is another measure of a person's fitness level and is the third of the "big three" bodyweight exercises in the Navy Seal BUD/S Physical Screening Test.
The individual starts in a supine position on the ground. The shoulders are curled towards the pelvis while the lower back remains flat against the floor. The focus is placed on contracting the abdominal muscles.
The Crunch It Up variant places the feet under a stationary object such as a low bed or couch. The arms are crossed over the stomach and the knees bent. Using the abdominal muscles, the torse is brought up just until the arms touch the thighs. The torso is then lowered to the starting position.
The V-Ups variant starts with the individual in a supine position with arms straight out on the ground and parallel to the body. The body is bent at the hips, the torso is raised off the ground and the legs brought to the chest with knees bent. The legs and torso are then lowered until they are just a few inches off the ground, but not touching it.
The Side-V variant starts with the individual on the ground, lying on one side of the body, with the arm closest to the ground stretched out perpendicular to the body. The other arm is bent and the hand placed behind the head. The torso is raised and the legs, kept straight, are raised until the legs form a 90-degree angle with the torso. The legs and torso are then lowered until they are just a few inches off the ground, but not touching it.
The Jack-Knife variant starts with the individual on the ground, legs stretched out straight and the arms on the ground extended straight up over the head. The chest and legs are simultaneously brought up until the hands touch the feet. The legs and torso are then lowered until they are just a few inches off the ground, but not touching it.
The Bicycle variant starts with the individual on the ground, the hands behind the head. The knee is pulled in toward the chest while the upper body curls up to touch the opposite elbow to the knee. The leg is then straightened and the exercise performed on the other side. The legs should be suspended off the ground during the exercise.