What is the proper technique for performing an abdominal crunch to effectively target and strengthen the core muscles?

To perform an effective abdominal crunch, lie on your back with knees bent and feet flat on the floor. Place hands behind your head or crossed over your chest. Engage your core muscles by pulling your belly button towards your spine. Slowly lift your head, neck, and shoulders off the floor, exhaling as you crunch up. Hold for a moment at the top, then slowly lower back down while inhaling. Repeat for desired number of repetitions, focusing on controlled movements and not straining your neck.