How do you perform a cross arm crunch exercise effectively to target your abdominal muscles?

To perform a cross arm crunch effectively, lie on your back with your knees bent and feet flat on the floor. Cross your arms over your chest. Engage your core muscles and lift your shoulders off the floor, bringing your chest towards your knees. Hold for a moment, then lower back down. Repeat for a set number of repetitions to target your abdominal muscles.