Ab Kickbacks - Men May 18, 2018 19:34 Main Muscle: Core, Quads Use ankle attachments. Begin in a straight arm plank position- back neutral, core tight. Crunch abs and bring knees forward towards chest. Jump legs to starting position. Repeat. Related articles Where do I get training videos? Where can I get copies of BodyBoss Product Manual and Workout Booklet? Shoulder Flys Instruction How do I join Club BodyBoss? Why are bands taking longer to ship?