The Biomechanics Lab at San Diego State University conducted a study to analyse 13 of the most common ab exercises and then ranked them from best to worst. Exercises included in the study were traditional crunches, modified crunches, partial bodyweight exercises, and exercises using home and gym equipment. Researchers measured activity in the upper and lower rectus abdominis, external obliques, and the rectus femoris. Exercises requiring constant ab stabilisation and body rotation created the most muscle activity in the obliques. The best exercise for working the obliques are the captain’s chair, bicycles and reverse crunch. The best exercise to target the rectus abdominis are the bicycles, captain’s chair and exercise-ball crunches.