What is your favorite core exercise? ADVERTISEMENT 2.14K viewsNovember 1, 2011 0 Monica November 1, 2011 0 Comments 32 Answers ActiveVotedNewestOldest 0 Susan Posted 0 Comments The plank because it engages all four abdominal muscle groups and there are so many ways to progress it. You are viewing 1 out of 32 answers, click here to view all answers. Register or Login