This curl up is commonly used to test abdominal endurance. Many fitness certifying organizations use the curl up as a protocol for exercise testing. This exercise is similar to the abdominal crunch. However, the range of motion is greater than the crunch.
First, lie down on an exercise mat with your knees bent and feet flat on the floor. Extend your arms straight forward. Place your palms flat on the ground. Next, curl up slowly using your abdominal muscles. Your hands should slide forward a few inches toward your heels. Be sure to keep your head up at all times. Slowly return to the starting position and repeat the exercise.
Lie down on an exercise mat. Arms straight forward, palms down.
Contract the abs, curl up. Move hands toward heels. Keep head up.
Return to starting point. Repeat.